1 files changed, 746 insertions, 840 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 042d221d33cc..b48cd597145d 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -41,32 +41,31 @@
 #include <linux/debug_locks.h>
 #include <linux/lockdep.h>
 #include <linux/idr.h>
+#include <linux/hashtable.h>
-#include "workqueue_sched.h"
+#include "workqueue_internal.h"
 enum {
        /*
-         * global_cwq flags
+         * worker_pool flags
         *
-         * A bound gcwq is either associated or disassociated with its CPU.
+         * A bound pool is either associated or disassociated with its CPU.
         * While associated (!DISASSOCIATED), all workers are bound to the
         * CPU and none has %WORKER_UNBOUND set and concurrency management
         * is in effect.
         *
         * While DISASSOCIATED, the cpu may be offline and all workers have
         * %WORKER_UNBOUND set and concurrency management disabled, and may
-         * be executing on any CPU.  The gcwq behaves as an unbound one.
+         * be executing on any CPU.  The pool behaves as an unbound one.
         *
         * Note that DISASSOCIATED can be flipped only while holding
-         * assoc_mutex of all pools on the gcwq to avoid changing binding
+         * assoc_mutex to avoid changing binding state while
-         * state while create_worker() is in progress.
+         * create_worker() is in progress.
         */
-        GCWQ_DISASSOCIATED      = 1 << 0,       /* cpu can't serve workers */
-        GCWQ_FREEZING           = 1 << 1,       /* freeze in progress */
-        /* pool flags */
        POOL_MANAGE_WORKERS     = 1 << 0,       /* need to manage workers */
        POOL_MANAGING_WORKERS   = 1 << 1,       /* managing workers */
+        POOL_DISASSOCIATED      = 1 << 2,       /* cpu can't serve workers */
+        POOL_FREEZING           = 1 << 3,       /* freeze in progress */
        /* worker flags */
        WORKER_STARTED          = 1 << 0,       /* started */
@@ -79,11 +78,9 @@ enum {
        WORKER_NOT_RUNNING      = WORKER_PREP | WORKER_UNBOUND |
                                  WORKER_CPU_INTENSIVE,
-        NR_WORKER_POOLS         = 2,            /* # worker pools per gcwq */
+        NR_STD_WORKER_POOLS     = 2,            /* # standard pools per cpu */
        BUSY_WORKER_HASH_ORDER  = 6,            /* 64 pointers */
-        BUSY_WORKER_HASH_SIZE   = 1 << BUSY_WORKER_HASH_ORDER,
-        BUSY_WORKER_HASH_MASK   = BUSY_WORKER_HASH_SIZE - 1,
        MAX_IDLE_WORKERS_RATIO  = 4,            /* 1/4 of busy can be idle */
        IDLE_WORKER_TIMEOUT     = 300 * HZ,     /* keep idle ones for 5 mins */
@@ -111,48 +108,24 @@ enum {
 * P: Preemption protected.  Disabling preemption is enough and should
 *    only be modified and accessed from the local cpu.
 *
- * L: gcwq->lock protected.  Access with gcwq->lock held.
+ * L: pool->lock protected.  Access with pool->lock held.
 *
- * X: During normal operation, modification requires gcwq->lock and
+ * X: During normal operation, modification requires pool->lock and should
- *    should be done only from local cpu.  Either disabling preemption
+ *    be done only from local cpu.  Either disabling preemption on local
- *    on local cpu or grabbing gcwq->lock is enough for read access.
+ *    cpu or grabbing pool->lock is enough for read access.  If
- *    If GCWQ_DISASSOCIATED is set, it's identical to L.
+ *    POOL_DISASSOCIATED is set, it's identical to L.
 *
 * F: wq->flush_mutex protected.
 *
 * W: workqueue_lock protected.
 */
-struct global_cwq;
+/* struct worker is defined in workqueue_internal.h */
-struct worker_pool;
-/*
- * The poor guys doing the actual heavy lifting.  All on-duty workers
- * are either serving the manager role, on idle list or on busy hash.
- */
-struct worker {
-        /* on idle list while idle, on busy hash table while busy */
-        union {
-                struct list_head        entry;  /* L: while idle */
-                struct hlist_node       hentry; /* L: while busy */
-        };
-        struct work_struct      *current_work;  /* L: work being processed */
-        struct cpu_workqueue_struct *current_cwq; /* L: current_work's cwq */
-        struct list_head        scheduled;      /* L: scheduled works */
-        struct task_struct      *task;          /* I: worker task */
-        struct worker_pool      *pool;          /* I: the associated pool */
-        /* 64 bytes boundary on 64bit, 32 on 32bit */
-        unsigned long           last_active;    /* L: last active timestamp */
-        unsigned int            flags;          /* X: flags */
-        int                     id;             /* I: worker id */
-        /* for rebinding worker to CPU */
-        struct work_struct      rebind_work;    /* L: for busy worker */
-};
 struct worker_pool {
-        struct global_cwq       *gcwq;          /* I: the owning gcwq */
+        spinlock_t              lock;           /* the pool lock */
+        unsigned int            cpu;            /* I: the associated cpu */
+        int                     id;             /* I: pool ID */
        unsigned int            flags;          /* X: flags */
        struct list_head        worklist;       /* L: list of pending works */
@@ -165,34 +138,28 @@ struct worker_pool {
        struct timer_list       idle_timer;     /* L: worker idle timeout */
        struct timer_list       mayday_timer;   /* L: SOS timer for workers */
-        struct mutex            assoc_mutex;    /* protect GCWQ_DISASSOCIATED */
+        /* workers are chained either in busy_hash or idle_list */
-        struct ida              worker_ida;     /* L: for worker IDs */
+        DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
-};
-/*
- * Global per-cpu workqueue.  There's one and only one for each cpu
- * and all works are queued and processed here regardless of their
- * target workqueues.
- */
-struct global_cwq {
-        spinlock_t              lock;           /* the gcwq lock */
-        unsigned int            cpu;            /* I: the associated cpu */
-        unsigned int            flags;          /* L: GCWQ_* flags */
-        /* workers are chained either in busy_hash or pool idle_list */
-        struct hlist_head       busy_hash[BUSY_WORKER_HASH_SIZE];
                                                /* L: hash of busy workers */
-        struct worker_pool      pools[NR_WORKER_POOLS];
+        struct mutex            assoc_mutex;    /* protect POOL_DISASSOCIATED */
-                                                /* normal and highpri pools */
+        struct ida              worker_ida;     /* L: for worker IDs */
+        /*
+         * The current concurrency level.  As it's likely to be accessed
+         * from other CPUs during try_to_wake_up(), put it in a separate
+         * cacheline.
+         */
+        atomic_t                nr_running ____cacheline_aligned_in_smp;
 } ____cacheline_aligned_in_smp;
 /*
- * The per-CPU workqueue.  The lower WORK_STRUCT_FLAG_BITS of
+ * The per-pool workqueue.  While queued, the lower WORK_STRUCT_FLAG_BITS
- * work_struct->data are used for flags and thus cwqs need to be
+ * of work_struct->data are used for flags and the remaining high bits
- * aligned at two's power of the number of flag bits.
+ * point to the pwq; thus, pwqs need to be aligned at two's power of the
+ * number of flag bits.
 */
-struct cpu_workqueue_struct {
+struct pool_workqueue {
        struct worker_pool      *pool;          /* I: the associated pool */
        struct workqueue_struct *wq;            /* I: the owning workqueue */
        int                     work_color;     /* L: current color */
@@ -241,16 +208,16 @@ typedef unsigned long mayday_mask_t;
 struct workqueue_struct {
        unsigned int            flags;          /* W: WQ_* flags */
        union {
-                struct cpu_workqueue_struct __percpu    *pcpu;
+                struct pool_workqueue __percpu          *pcpu;
-                struct cpu_workqueue_struct             *single;
+                struct pool_workqueue                   *single;
                unsigned long                           v;
-        } cpu_wq;                               /* I: cwq's */
+        } pool_wq;                              /* I: pwq's */
        struct list_head        list;           /* W: list of all workqueues */
        struct mutex            flush_mutex;    /* protects wq flushing */
        int                     work_color;     /* F: current work color */
        int                     flush_color;    /* F: current flush color */
-        atomic_t                nr_cwqs_to_flush; /* flush in progress */
+        atomic_t                nr_pwqs_to_flush; /* flush in progress */
        struct wq_flusher       *first_flusher; /* F: first flusher */
        struct list_head        flusher_queue;  /* F: flush waiters */
        struct list_head        flusher_overflow; /* F: flush overflow list */
@@ -259,7 +226,7 @@ struct workqueue_struct {
        struct worker           *rescuer;       /* I: rescue worker */
        int                     nr_drainers;    /* W: drain in progress */
-        int                     saved_max_active; /* W: saved cwq max_active */
+        int                     saved_max_active; /* W: saved pwq max_active */
 #ifdef CONFIG_LOCKDEP
        struct lockdep_map      lockdep_map;
 #endif
@@ -280,16 +247,15 @@ EXPORT_SYMBOL_GPL(system_freezable_wq);
 #define CREATE_TRACE_POINTS
 #include <trace/events/workqueue.h>
-#define for_each_worker_pool(pool, gcwq)                                \
+#define for_each_std_worker_pool(pool, cpu)                             \
-        for ((pool) = &(gcwq)->pools[0];                                \
+        for ((pool) = &std_worker_pools(cpu)[0];                        \
-             (pool) < &(gcwq)->pools[NR_WORKER_POOLS]; (pool)++)
+             (pool) < &std_worker_pools(cpu)[NR_STD_WORKER_POOLS]; (pool)++)
-#define for_each_busy_worker(worker, i, pos, gcwq)                      \
+#define for_each_busy_worker(worker, i, pool)                           \
-        for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)                     \
+        hash_for_each(pool->busy_hash, i, worker, hentry)
-                hlist_for_each_entry(worker, pos, &gcwq->busy_hash[i], hentry)
-static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask,
+static inline int __next_wq_cpu(int cpu, const struct cpumask *mask,
-                                  unsigned int sw)
+                                unsigned int sw)
 {
        if (cpu < nr_cpu_ids) {
                if (sw & 1) {
@@ -300,42 +266,42 @@ static inline int __next_gcwq_cpu(int cpu, const struct cpumask *mask,
                if (sw & 2)
                        return WORK_CPU_UNBOUND;
        }
-        return WORK_CPU_NONE;
+        return WORK_CPU_END;
 }
-static inline int __next_wq_cpu(int cpu, const struct cpumask *mask,
+static inline int __next_pwq_cpu(int cpu, const struct cpumask *mask,
-                                struct workqueue_struct *wq)
+                                 struct workqueue_struct *wq)
 {
-        return __next_gcwq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2);
+        return __next_wq_cpu(cpu, mask, !(wq->flags & WQ_UNBOUND) ? 1 : 2);
 }
 /*
 * CPU iterators
 *
- * An extra gcwq is defined for an invalid cpu number
+ * An extra cpu number is defined using an invalid cpu number
 * (WORK_CPU_UNBOUND) to host workqueues which are not bound to any
- * specific CPU.  The following iterators are similar to
+ * specific CPU.  The following iterators are similar to for_each_*_cpu()
- * for_each_*_cpu() iterators but also considers the unbound gcwq.
+ * iterators but also considers the unbound CPU.
 *
- * for_each_gcwq_cpu()          : possible CPUs + WORK_CPU_UNBOUND
+ * for_each_wq_cpu()            : possible CPUs + WORK_CPU_UNBOUND
- * for_each_online_gcwq_cpu()   : online CPUs + WORK_CPU_UNBOUND
+ * for_each_online_wq_cpu()     : online CPUs + WORK_CPU_UNBOUND
- * for_each_cwq_cpu()           : possible CPUs for bound workqueues,
+ * for_each_pwq_cpu()           : possible CPUs for bound workqueues,
 *                                WORK_CPU_UNBOUND for unbound workqueues
 */
-#define for_each_gcwq_cpu(cpu)                                          \
+#define for_each_wq_cpu(cpu)                                            \
-        for ((cpu) = __next_gcwq_cpu(-1, cpu_possible_mask, 3);         \
+        for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, 3);           \
-             (cpu) < WORK_CPU_NONE;                                     \
+             (cpu) < WORK_CPU_END;                                      \
-             (cpu) = __next_gcwq_cpu((cpu), cpu_possible_mask, 3))
+             (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, 3))
-#define for_each_online_gcwq_cpu(cpu)                                   \
+#define for_each_online_wq_cpu(cpu)                                     \
-        for ((cpu) = __next_gcwq_cpu(-1, cpu_online_mask, 3);           \
+        for ((cpu) = __next_wq_cpu(-1, cpu_online_mask, 3);             \
-             (cpu) < WORK_CPU_NONE;                                     \
+             (cpu) < WORK_CPU_END;                                      \
-             (cpu) = __next_gcwq_cpu((cpu), cpu_online_mask, 3))
+             (cpu) = __next_wq_cpu((cpu), cpu_online_mask, 3))
-#define for_each_cwq_cpu(cpu, wq)                                       \
+#define for_each_pwq_cpu(cpu, wq)                                       \
-        for ((cpu) = __next_wq_cpu(-1, cpu_possible_mask, (wq));        \
+        for ((cpu) = __next_pwq_cpu(-1, cpu_possible_mask, (wq));       \
-             (cpu) < WORK_CPU_NONE;                                     \
+             (cpu) < WORK_CPU_END;                                      \
-             (cpu) = __next_wq_cpu((cpu), cpu_possible_mask, (wq)))
+             (cpu) = __next_pwq_cpu((cpu), cpu_possible_mask, (wq)))
 #ifdef CONFIG_DEBUG_OBJECTS_WORK
@@ -459,57 +425,70 @@ static LIST_HEAD(workqueues);
 static bool workqueue_freezing;         /* W: have wqs started freezing? */
 /*
- * The almighty global cpu workqueues.  nr_running is the only field
+ * The CPU and unbound standard worker pools.  The unbound ones have
- * which is expected to be used frequently by other cpus via
+ * POOL_DISASSOCIATED set, and their workers have WORKER_UNBOUND set.
- * try_to_wake_up().  Put it in a separate cacheline.
 */
-static DEFINE_PER_CPU(struct global_cwq, global_cwq);
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS],
-static DEFINE_PER_CPU_SHARED_ALIGNED(atomic_t, pool_nr_running[NR_WORKER_POOLS]);
+                                     cpu_std_worker_pools);
+static struct worker_pool unbound_std_worker_pools[NR_STD_WORKER_POOLS];
-/*
+/* idr of all pools */
- * Global cpu workqueue and nr_running counter for unbound gcwq.  The
+static DEFINE_MUTEX(worker_pool_idr_mutex);
- * gcwq is always online, has GCWQ_DISASSOCIATED set, and all its
+static DEFINE_IDR(worker_pool_idr);
- * workers have WORKER_UNBOUND set.
- */
-static struct global_cwq unbound_global_cwq;
-static atomic_t unbound_pool_nr_running[NR_WORKER_POOLS] = {
-        [0 ... NR_WORKER_POOLS - 1]     = ATOMIC_INIT(0),       /* always 0 */
-};
 static int worker_thread(void *__worker);
-static int worker_pool_pri(struct worker_pool *pool)
+static struct worker_pool *std_worker_pools(int cpu)
+{
+        if (cpu != WORK_CPU_UNBOUND)
+                return per_cpu(cpu_std_worker_pools, cpu);
+        else
+                return unbound_std_worker_pools;
+}
+static int std_worker_pool_pri(struct worker_pool *pool)
 {
-        return pool - pool->gcwq->pools;
+        return pool - std_worker_pools(pool->cpu);
 }
-static struct global_cwq *get_gcwq(unsigned int cpu)
+/* allocate ID and assign it to @pool */
+static int worker_pool_assign_id(struct worker_pool *pool)
 {
-        if (cpu != WORK_CPU_UNBOUND)
+        int ret;
-                return &per_cpu(global_cwq, cpu);
-        else
+        mutex_lock(&worker_pool_idr_mutex);
-                return &unbound_global_cwq;
+        ret = idr_alloc(&worker_pool_idr, pool, 0, 0, GFP_KERNEL);
+        if (ret >= 0)
+                pool->id = ret;
+        mutex_unlock(&worker_pool_idr_mutex);
+        return ret < 0 ? ret : 0;
 }
-static atomic_t *get_pool_nr_running(struct worker_pool *pool)
+/*
+ * Lookup worker_pool by id.  The idr currently is built during boot and
+ * never modified.  Don't worry about locking for now.
+ */
+static struct worker_pool *worker_pool_by_id(int pool_id)
 {
-        int cpu = pool->gcwq->cpu;
+        return idr_find(&worker_pool_idr, pool_id);
-        int idx = worker_pool_pri(pool);
+}
-        if (cpu != WORK_CPU_UNBOUND)
+static struct worker_pool *get_std_worker_pool(int cpu, bool highpri)
-                return &per_cpu(pool_nr_running, cpu)[idx];
+{
-        else
+        struct worker_pool *pools = std_worker_pools(cpu);
-                return &unbound_pool_nr_running[idx];
+        return &pools[highpri];
 }
-static struct cpu_workqueue_struct *get_cwq(unsigned int cpu,
+static struct pool_workqueue *get_pwq(unsigned int cpu,
-                                            struct workqueue_struct *wq)
+                                      struct workqueue_struct *wq)
 {
        if (!(wq->flags & WQ_UNBOUND)) {
                if (likely(cpu < nr_cpu_ids))
-                        return per_cpu_ptr(wq->cpu_wq.pcpu, cpu);
+                        return per_cpu_ptr(wq->pool_wq.pcpu, cpu);
        } else if (likely(cpu == WORK_CPU_UNBOUND))
-                return wq->cpu_wq.single;
+                return wq->pool_wq.single;
        return NULL;
 }
@@ -530,19 +509,19 @@ static int work_next_color(int color)
 }
 /*
- * While queued, %WORK_STRUCT_CWQ is set and non flag bits of a work's data
+ * While queued, %WORK_STRUCT_PWQ is set and non flag bits of a work's data
- * contain the pointer to the queued cwq.  Once execution starts, the flag
+ * contain the pointer to the queued pwq.  Once execution starts, the flag
- * is cleared and the high bits contain OFFQ flags and CPU number.
+ * is cleared and the high bits contain OFFQ flags and pool ID.
 *
- * set_work_cwq(), set_work_cpu_and_clear_pending(), mark_work_canceling()
+ * set_work_pwq(), set_work_pool_and_clear_pending(), mark_work_canceling()
- * and clear_work_data() can be used to set the cwq, cpu or clear
+ * and clear_work_data() can be used to set the pwq, pool or clear
 * work->data.  These functions should only be called while the work is
 * owned - ie. while the PENDING bit is set.
 *
- * get_work_[g]cwq() can be used to obtain the gcwq or cwq corresponding to
+ * get_work_pool() and get_work_pwq() can be used to obtain the pool or pwq
- * a work.  gcwq is available once the work has been queued anywhere after
+ * corresponding to a work.  Pool is available once the work has been
- * initialization until it is sync canceled.  cwq is available only while
+ * queued anywhere after initialization until it is sync canceled.  pwq is
- * the work item is queued.
+ * available only while the work item is queued.
 *
 * %WORK_OFFQ_CANCELING is used to mark a work item which is being
 * canceled.  While being canceled, a work item may have its PENDING set
@@ -556,16 +535,22 @@ static inline void set_work_data(struct work_struct *work, unsigned long data,
        atomic_long_set(&work->data, data | flags | work_static(work));
 }
-static void set_work_cwq(struct work_struct *work,
+static void set_work_pwq(struct work_struct *work, struct pool_workqueue *pwq,
-                         struct cpu_workqueue_struct *cwq,
                         unsigned long extra_flags)
 {
-        set_work_data(work, (unsigned long)cwq,
+        set_work_data(work, (unsigned long)pwq,
-                      WORK_STRUCT_PENDING | WORK_STRUCT_CWQ | extra_flags);
+                      WORK_STRUCT_PENDING | WORK_STRUCT_PWQ | extra_flags);
 }
-static void set_work_cpu_and_clear_pending(struct work_struct *work,
+static void set_work_pool_and_keep_pending(struct work_struct *work,
-                                           unsigned int cpu)
+                                           int pool_id)
+{
+        set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT,
+                      WORK_STRUCT_PENDING);
+}
+static void set_work_pool_and_clear_pending(struct work_struct *work,
+                                            int pool_id)
 {
        /*
         * The following wmb is paired with the implied mb in
@@ -574,67 +559,92 @@ static void set_work_cpu_and_clear_pending(struct work_struct *work,
         * owner.
         */
        smp_wmb();
-        set_work_data(work, (unsigned long)cpu << WORK_OFFQ_CPU_SHIFT, 0);
+        set_work_data(work, (unsigned long)pool_id << WORK_OFFQ_POOL_SHIFT, 0);
 }
 static void clear_work_data(struct work_struct *work)
 {
-        smp_wmb();      /* see set_work_cpu_and_clear_pending() */
+        smp_wmb();      /* see set_work_pool_and_clear_pending() */
-        set_work_data(work, WORK_STRUCT_NO_CPU, 0);
+        set_work_data(work, WORK_STRUCT_NO_POOL, 0);
 }
-static struct cpu_workqueue_struct *get_work_cwq(struct work_struct *work)
+static struct pool_workqueue *get_work_pwq(struct work_struct *work)
 {
        unsigned long data = atomic_long_read(&work->data);
-        if (data & WORK_STRUCT_CWQ)
+        if (data & WORK_STRUCT_PWQ)
                return (void *)(data & WORK_STRUCT_WQ_DATA_MASK);
        else
                return NULL;
 }
-static struct global_cwq *get_work_gcwq(struct work_struct *work)
+/**
+ * get_work_pool - return the worker_pool a given work was associated with
+ * @work: the work item of interest
+ *
+ * Return the worker_pool @work was last associated with.  %NULL if none.
+ */
+static struct worker_pool *get_work_pool(struct work_struct *work)
 {
        unsigned long data = atomic_long_read(&work->data);
-        unsigned int cpu;
+        struct worker_pool *pool;
+        int pool_id;
-        if (data & WORK_STRUCT_CWQ)
+        if (data & WORK_STRUCT_PWQ)
-                return ((struct cpu_workqueue_struct *)
+                return ((struct pool_workqueue *)
-                        (data & WORK_STRUCT_WQ_DATA_MASK))->pool->gcwq;
+                        (data & WORK_STRUCT_WQ_DATA_MASK))->pool;
-        cpu = data >> WORK_OFFQ_CPU_SHIFT;
+        pool_id = data >> WORK_OFFQ_POOL_SHIFT;
-        if (cpu == WORK_CPU_NONE)
+        if (pool_id == WORK_OFFQ_POOL_NONE)
                return NULL;
-        BUG_ON(cpu >= nr_cpu_ids && cpu != WORK_CPU_UNBOUND);
+        pool = worker_pool_by_id(pool_id);
-        return get_gcwq(cpu);
+        WARN_ON_ONCE(!pool);
+        return pool;
+}
+/**
+ * get_work_pool_id - return the worker pool ID a given work is associated with
+ * @work: the work item of interest
+ *
+ * Return the worker_pool ID @work was last associated with.
+ * %WORK_OFFQ_POOL_NONE if none.
+ */
+static int get_work_pool_id(struct work_struct *work)
+{
+        unsigned long data = atomic_long_read(&work->data);
+        if (data & WORK_STRUCT_PWQ)
+                return ((struct pool_workqueue *)
+                        (data & WORK_STRUCT_WQ_DATA_MASK))->pool->id;
+        return data >> WORK_OFFQ_POOL_SHIFT;
 }
 static void mark_work_canceling(struct work_struct *work)
 {
-        struct global_cwq *gcwq = get_work_gcwq(work);
+        unsigned long pool_id = get_work_pool_id(work);
-        unsigned long cpu = gcwq ? gcwq->cpu : WORK_CPU_NONE;
-        set_work_data(work, (cpu << WORK_OFFQ_CPU_SHIFT) | WORK_OFFQ_CANCELING,
+        pool_id <<= WORK_OFFQ_POOL_SHIFT;
-                      WORK_STRUCT_PENDING);
+        set_work_data(work, pool_id | WORK_OFFQ_CANCELING, WORK_STRUCT_PENDING);
 }
 static bool work_is_canceling(struct work_struct *work)
 {
        unsigned long data = atomic_long_read(&work->data);
-        return !(data & WORK_STRUCT_CWQ) && (data & WORK_OFFQ_CANCELING);
+        return !(data & WORK_STRUCT_PWQ) && (data & WORK_OFFQ_CANCELING);
 }
 /*
 * Policy functions.  These define the policies on how the global worker
 * pools are managed.  Unless noted otherwise, these functions assume that
- * they're being called with gcwq->lock held.
+ * they're being called with pool->lock held.
 */
 static bool __need_more_worker(struct worker_pool *pool)
 {
-        return !atomic_read(get_pool_nr_running(pool));
+        return !atomic_read(&pool->nr_running);
 }
 /*
@@ -642,7 +652,7 @@ static bool __need_more_worker(struct worker_pool *pool)
 * running workers.
 *
 * Note that, because unbound workers never contribute to nr_running, this
- * function will always return %true for unbound gcwq as long as the
+ * function will always return %true for unbound pools as long as the
 * worklist isn't empty.
 */
 static bool need_more_worker(struct worker_pool *pool)
@@ -659,9 +669,8 @@ static bool may_start_working(struct worker_pool *pool)
 /* Do I need to keep working?  Called from currently running workers. */
 static bool keep_working(struct worker_pool *pool)
 {
-        atomic_t *nr_running = get_pool_nr_running(pool);
+        return !list_empty(&pool->worklist) &&
+                atomic_read(&pool->nr_running) <= 1;
-        return !list_empty(&pool->worklist) && atomic_read(nr_running) <= 1;
 }
 /* Do we need a new worker?  Called from manager. */
@@ -714,7 +723,7 @@ static struct worker *first_worker(struct worker_pool *pool)
 * Wake up the first idle worker of @pool.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
 static void wake_up_worker(struct worker_pool *pool)
 {
@@ -739,8 +748,10 @@ void wq_worker_waking_up(struct task_struct *task, unsigned int cpu)
 {
        struct worker *worker = kthread_data(task);
-        if (!(worker->flags & WORKER_NOT_RUNNING))
+        if (!(worker->flags & WORKER_NOT_RUNNING)) {
-                atomic_inc(get_pool_nr_running(worker->pool));
+                WARN_ON_ONCE(worker->pool->cpu != cpu);
+                atomic_inc(&worker->pool->nr_running);
+        }
 }
 /**
@@ -762,12 +773,18 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task,
                                       unsigned int cpu)
 {
        struct worker *worker = kthread_data(task), *to_wakeup = NULL;
-        struct worker_pool *pool = worker->pool;
+        struct worker_pool *pool;
-        atomic_t *nr_running = get_pool_nr_running(pool);
+        /*
+         * Rescuers, which may not have all the fields set up like normal
+         * workers, also reach here, let's not access anything before
+         * checking NOT_RUNNING.
+         */
        if (worker->flags & WORKER_NOT_RUNNING)
                return NULL;
+        pool = worker->pool;
        /* this can only happen on the local cpu */
        BUG_ON(cpu != raw_smp_processor_id());
@@ -779,10 +796,11 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task,
         * NOT_RUNNING is clear.  This means that we're bound to and
         * running on the local cpu w/ rq lock held and preemption
         * disabled, which in turn means that none else could be
-         * manipulating idle_list, so dereferencing idle_list without gcwq
+         * manipulating idle_list, so dereferencing idle_list without pool
         * lock is safe.
         */
-        if (atomic_dec_and_test(nr_running) && !list_empty(&pool->worklist))
+        if (atomic_dec_and_test(&pool->nr_running) &&
+            !list_empty(&pool->worklist))
                to_wakeup = first_worker(pool);
        return to_wakeup ? to_wakeup->task : NULL;
 }
@@ -798,7 +816,7 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task,
 * woken up.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock)
+ * spin_lock_irq(pool->lock)
 */
 static inline void worker_set_flags(struct worker *worker, unsigned int flags,
                                    bool wakeup)
@@ -814,14 +832,12 @@ static inline void worker_set_flags(struct worker *worker, unsigned int flags,
         */
        if ((flags & WORKER_NOT_RUNNING) &&
            !(worker->flags & WORKER_NOT_RUNNING)) {
-                atomic_t *nr_running = get_pool_nr_running(pool);
                if (wakeup) {
-                        if (atomic_dec_and_test(nr_running) &&
+                        if (atomic_dec_and_test(&pool->nr_running) &&
                            !list_empty(&pool->worklist))
                                wake_up_worker(pool);
                } else
-                        atomic_dec(nr_running);
+                        atomic_dec(&pool->nr_running);
        }
        worker->flags |= flags;
@@ -835,7 +851,7 @@ static inline void worker_set_flags(struct worker *worker, unsigned int flags,
 * Clear @flags in @worker->flags and adjust nr_running accordingly.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock)
+ * spin_lock_irq(pool->lock)
 */
 static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
 {
@@ -853,87 +869,55 @@ static inline void worker_clr_flags(struct worker *worker, unsigned int flags)
         */
        if ((flags & WORKER_NOT_RUNNING) && (oflags & WORKER_NOT_RUNNING))
                if (!(worker->flags & WORKER_NOT_RUNNING))
-                        atomic_inc(get_pool_nr_running(pool));
+                        atomic_inc(&pool->nr_running);
 }
 /**
- * busy_worker_head - return the busy hash head for a work
+ * find_worker_executing_work - find worker which is executing a work
- * @gcwq: gcwq of interest
+ * @pool: pool of interest
- * @work: work to be hashed
- *
- * Return hash head of @gcwq for @work.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
- *
- * RETURNS:
- * Pointer to the hash head.
- */
-static struct hlist_head *busy_worker_head(struct global_cwq *gcwq,
-                                           struct work_struct *work)
-{
-        const int base_shift = ilog2(sizeof(struct work_struct));
-        unsigned long v = (unsigned long)work;
-        /* simple shift and fold hash, do we need something better? */
-        v >>= base_shift;
-        v += v >> BUSY_WORKER_HASH_ORDER;
-        v &= BUSY_WORKER_HASH_MASK;
-        return &gcwq->busy_hash[v];
-}
-/**
- * __find_worker_executing_work - find worker which is executing a work
- * @gcwq: gcwq of interest
- * @bwh: hash head as returned by busy_worker_head()
 * @work: work to find worker for
 *
- * Find a worker which is executing @work on @gcwq.  @bwh should be
+ * Find a worker which is executing @work on @pool by searching
- * the hash head obtained by calling busy_worker_head() with the same
+ * @pool->busy_hash which is keyed by the address of @work.  For a worker
- * work.
+ * to match, its current execution should match the address of @work and
+ * its work function.  This is to avoid unwanted dependency between
+ * unrelated work executions through a work item being recycled while still
+ * being executed.
+ *
+ * This is a bit tricky.  A work item may be freed once its execution
+ * starts and nothing prevents the freed area from being recycled for
+ * another work item.  If the same work item address ends up being reused
+ * before the original execution finishes, workqueue will identify the
+ * recycled work item as currently executing and make it wait until the
+ * current execution finishes, introducing an unwanted dependency.
+ *
+ * This function checks the work item address, work function and workqueue
+ * to avoid false positives.  Note that this isn't complete as one may
+ * construct a work function which can introduce dependency onto itself
+ * through a recycled work item.  Well, if somebody wants to shoot oneself
+ * in the foot that badly, there's only so much we can do, and if such
+ * deadlock actually occurs, it should be easy to locate the culprit work
+ * function.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 *
 * RETURNS:
 * Pointer to worker which is executing @work if found, NULL
 * otherwise.
 */
-static struct worker *__find_worker_executing_work(struct global_cwq *gcwq,
+static struct worker *find_worker_executing_work(struct worker_pool *pool,
-                                                   struct hlist_head *bwh,
+                                                 struct work_struct *work)
-                                                   struct work_struct *work)
 {
        struct worker *worker;
-        struct hlist_node *tmp;
-        hlist_for_each_entry(worker, tmp, bwh, hentry)
+        hash_for_each_possible(pool->busy_hash, worker, hentry,
-                if (worker->current_work == work)
+                               (unsigned long)work)
+                if (worker->current_work == work &&
+                    worker->current_func == work->func)
                        return worker;
-        return NULL;
-}
-/**
+        return NULL;
- * find_worker_executing_work - find worker which is executing a work
- * @gcwq: gcwq of interest
- * @work: work to find worker for
- *
- * Find a worker which is executing @work on @gcwq.  This function is
- * identical to __find_worker_executing_work() except that this
- * function calculates @bwh itself.
- *
- * CONTEXT:
- * spin_lock_irq(gcwq->lock).
- *
- * RETURNS:
- * Pointer to worker which is executing @work if found, NULL
- * otherwise.
- */
-static struct worker *find_worker_executing_work(struct global_cwq *gcwq,
-                                                 struct work_struct *work)
-{
-        return __find_worker_executing_work(gcwq, busy_worker_head(gcwq, work),
-                                            work);
 }
 /**
@@ -951,7 +935,7 @@ static struct worker *find_worker_executing_work(struct global_cwq *gcwq,
 * nested inside outer list_for_each_entry_safe().
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
 static void move_linked_works(struct work_struct *work, struct list_head *head,
                              struct work_struct **nextp)
@@ -977,67 +961,67 @@ static void move_linked_works(struct work_struct *work, struct list_head *head,
                *nextp = n;
 }
-static void cwq_activate_delayed_work(struct work_struct *work)
+static void pwq_activate_delayed_work(struct work_struct *work)
 {
-        struct cpu_workqueue_struct *cwq = get_work_cwq(work);
+        struct pool_workqueue *pwq = get_work_pwq(work);
        trace_workqueue_activate_work(work);
-        move_linked_works(work, &cwq->pool->worklist, NULL);
+        move_linked_works(work, &pwq->pool->worklist, NULL);
        __clear_bit(WORK_STRUCT_DELAYED_BIT, work_data_bits(work));
-        cwq->nr_active++;
+        pwq->nr_active++;
 }
-static void cwq_activate_first_delayed(struct cpu_workqueue_struct *cwq)
+static void pwq_activate_first_delayed(struct pool_workqueue *pwq)
 {
-        struct work_struct *work = list_first_entry(&cwq->delayed_works,
+        struct work_struct *work = list_first_entry(&pwq->delayed_works,
                                                    struct work_struct, entry);
-        cwq_activate_delayed_work(work);
+        pwq_activate_delayed_work(work);
 }
 /**
- * cwq_dec_nr_in_flight - decrement cwq's nr_in_flight
+ * pwq_dec_nr_in_flight - decrement pwq's nr_in_flight
- * @cwq: cwq of interest
+ * @pwq: pwq of interest
 * @color: color of work which left the queue
 *
 * A work either has completed or is removed from pending queue,
- * decrement nr_in_flight of its cwq and handle workqueue flushing.
+ * decrement nr_in_flight of its pwq and handle workqueue flushing.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
-static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color)
+static void pwq_dec_nr_in_flight(struct pool_workqueue *pwq, int color)
 {
        /* ignore uncolored works */
        if (color == WORK_NO_COLOR)
                return;
-        cwq->nr_in_flight[color]--;
+        pwq->nr_in_flight[color]--;
-        cwq->nr_active--;
+        pwq->nr_active--;
-        if (!list_empty(&cwq->delayed_works)) {
+        if (!list_empty(&pwq->delayed_works)) {
                /* one down, submit a delayed one */
-                if (cwq->nr_active < cwq->max_active)
+                if (pwq->nr_active < pwq->max_active)
-                        cwq_activate_first_delayed(cwq);
+                        pwq_activate_first_delayed(pwq);
        }
        /* is flush in progress and are we at the flushing tip? */
-        if (likely(cwq->flush_color != color))
+        if (likely(pwq->flush_color != color))
                return;
        /* are there still in-flight works? */
-        if (cwq->nr_in_flight[color])
+        if (pwq->nr_in_flight[color])
                return;
-        /* this cwq is done, clear flush_color */
+        /* this pwq is done, clear flush_color */
-        cwq->flush_color = -1;
+        pwq->flush_color = -1;
        /*
-         * If this was the last cwq, wake up the first flusher.  It
+         * If this was the last pwq, wake up the first flusher.  It
         * will handle the rest.
         */
-        if (atomic_dec_and_test(&cwq->wq->nr_cwqs_to_flush))
+        if (atomic_dec_and_test(&pwq->wq->nr_pwqs_to_flush))
-                complete(&cwq->wq->first_flusher->done);
+                complete(&pwq->wq->first_flusher->done);
 }
 /**
@@ -1068,7 +1052,8 @@ static void cwq_dec_nr_in_flight(struct cpu_workqueue_struct *cwq, int color)
 static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
                               unsigned long *flags)
 {
-        struct global_cwq *gcwq;
+        struct worker_pool *pool;
+        struct pool_workqueue *pwq;
        local_irq_save(*flags);
@@ -1093,41 +1078,43 @@ static int try_to_grab_pending(struct work_struct *work, bool is_dwork,
         * The queueing is in progress, or it is already queued. Try to
         * steal it from ->worklist without clearing WORK_STRUCT_PENDING.
         */
-        gcwq = get_work_gcwq(work);
+        pool = get_work_pool(work);
-        if (!gcwq)
+        if (!pool)
                goto fail;
-        spin_lock(&gcwq->lock);
+        spin_lock(&pool->lock);
-        if (!list_empty(&work->entry)) {
+        /*
+         * work->data is guaranteed to point to pwq only while the work
+         * item is queued on pwq->wq, and both updating work->data to point
+         * to pwq on queueing and to pool on dequeueing are done under
+         * pwq->pool->lock.  This in turn guarantees that, if work->data
+         * points to pwq which is associated with a locked pool, the work
+         * item is currently queued on that pool.
+         */
+        pwq = get_work_pwq(work);
+        if (pwq && pwq->pool == pool) {
+                debug_work_deactivate(work);
                /*
-                 * This work is queued, but perhaps we locked the wrong gcwq.
+                 * A delayed work item cannot be grabbed directly because
-                 * In that case we must see the new value after rmb(), see
+                 * it might have linked NO_COLOR work items which, if left
-                 * insert_work()->wmb().
+                 * on the delayed_list, will confuse pwq->nr_active
+                 * management later on and cause stall.  Make sure the work
+                 * item is activated before grabbing.
                 */
-                smp_rmb();
+                if (*work_data_bits(work) & WORK_STRUCT_DELAYED)
-                if (gcwq == get_work_gcwq(work)) {
+                        pwq_activate_delayed_work(work);
-                        debug_work_deactivate(work);
-                        /*
+                list_del_init(&work->entry);
-                         * A delayed work item cannot be grabbed directly
+                pwq_dec_nr_in_flight(get_work_pwq(work), get_work_color(work));
-                         * because it might have linked NO_COLOR work items
-                         * which, if left on the delayed_list, will confuse
-                         * cwq->nr_active management later on and cause
-                         * stall.  Make sure the work item is activated
-                         * before grabbing.
-                         */
-                        if (*work_data_bits(work) & WORK_STRUCT_DELAYED)
-                                cwq_activate_delayed_work(work);
-                        list_del_init(&work->entry);
+                /* work->data points to pwq iff queued, point to pool */
-                        cwq_dec_nr_in_flight(get_work_cwq(work),
+                set_work_pool_and_keep_pending(work, pool->id);
-                                get_work_color(work));
-                        spin_unlock(&gcwq->lock);
+                spin_unlock(&pool->lock);
-                        return 1;
+                return 1;
-                }
        }
-        spin_unlock(&gcwq->lock);
+        spin_unlock(&pool->lock);
 fail:
        local_irq_restore(*flags);
        if (work_is_canceling(work))
@@ -1137,33 +1124,25 @@ fail:
 }
 /**
- * insert_work - insert a work into gcwq
+ * insert_work - insert a work into a pool
- * @cwq: cwq @work belongs to
+ * @pwq: pwq @work belongs to
 * @work: work to insert
 * @head: insertion point
 * @extra_flags: extra WORK_STRUCT_* flags to set
 *
- * Insert @work which belongs to @cwq into @gcwq after @head.
+ * Insert @work which belongs to @pwq after @head.  @extra_flags is or'd to
- * @extra_flags is or'd to work_struct flags.
+ * work_struct flags.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
-static void insert_work(struct cpu_workqueue_struct *cwq,
+static void insert_work(struct pool_workqueue *pwq, struct work_struct *work,
-                        struct work_struct *work, struct list_head *head,
+                        struct list_head *head, unsigned int extra_flags)
-                        unsigned int extra_flags)
 {
-        struct worker_pool *pool = cwq->pool;
+        struct worker_pool *pool = pwq->pool;
        /* we own @work, set data and link */
-        set_work_cwq(work, cwq, extra_flags);
+        set_work_pwq(work, pwq, extra_flags);
-        /*
-         * Ensure that we get the right work->data if we see the
-         * result of list_add() below, see try_to_grab_pending().
-         */
-        smp_wmb();
        list_add_tail(&work->entry, head);
        /*
@@ -1179,41 +1158,24 @@ static void insert_work(struct cpu_workqueue_struct *cwq,
 /*
 * Test whether @work is being queued from another work executing on the
- * same workqueue.  This is rather expensive and should only be used from
+ * same workqueue.
- * cold paths.
 */
 static bool is_chained_work(struct workqueue_struct *wq)
 {
-        unsigned long flags;
+        struct worker *worker;
-        unsigned int cpu;
-        for_each_gcwq_cpu(cpu) {
-                struct global_cwq *gcwq = get_gcwq(cpu);
-                struct worker *worker;
-                struct hlist_node *pos;
-                int i;
-                spin_lock_irqsave(&gcwq->lock, flags);
+        worker = current_wq_worker();
-                for_each_busy_worker(worker, i, pos, gcwq) {
+        /*
-                        if (worker->task != current)
+         * Return %true iff I'm a worker execuing a work item on @wq.  If
-                                continue;
+         * I'm @worker, it's safe to dereference it without locking.
-                        spin_unlock_irqrestore(&gcwq->lock, flags);
+         */
-                        /*
+        return worker && worker->current_pwq->wq == wq;
-                         * I'm @worker, no locking necessary.  See if @work
-                         * is headed to the same workqueue.
-                         */
-                        return worker->current_cwq->wq == wq;
-                }
-                spin_unlock_irqrestore(&gcwq->lock, flags);
-        }
-        return false;
 }
 static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
                         struct work_struct *work)
 {
-        struct global_cwq *gcwq;
+        struct pool_workqueue *pwq;
-        struct cpu_workqueue_struct *cwq;
        struct list_head *worklist;
        unsigned int work_flags;
        unsigned int req_cpu = cpu;
@@ -1233,9 +1195,9 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
            WARN_ON_ONCE(!is_chained_work(wq)))
                return;
-        /* determine gcwq to use */
+        /* determine the pwq to use */
        if (!(wq->flags & WQ_UNBOUND)) {
-                struct global_cwq *last_gcwq;
+                struct worker_pool *last_pool;
                if (cpu == WORK_CPU_UNBOUND)
                        cpu = raw_smp_processor_id();
@@ -1246,55 +1208,54 @@ static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
                 * work needs to be queued on that cpu to guarantee
                 * non-reentrancy.
                 */
-                gcwq = get_gcwq(cpu);
+                pwq = get_pwq(cpu, wq);
-                last_gcwq = get_work_gcwq(work);
+                last_pool = get_work_pool(work);
-                if (last_gcwq && last_gcwq != gcwq) {
+                if (last_pool && last_pool != pwq->pool) {
                        struct worker *worker;
-                        spin_lock(&last_gcwq->lock);
+                        spin_lock(&last_pool->lock);
-                        worker = find_worker_executing_work(last_gcwq, work);
+                        worker = find_worker_executing_work(last_pool, work);
-                        if (worker && worker->current_cwq->wq == wq)
+                        if (worker && worker->current_pwq->wq == wq) {
-                                gcwq = last_gcwq;
+                                pwq = get_pwq(last_pool->cpu, wq);
-                        else {
+                        } else {
                                /* meh... not running there, queue here */
-                                spin_unlock(&last_gcwq->lock);
+                                spin_unlock(&last_pool->lock);
-                                spin_lock(&gcwq->lock);
+                                spin_lock(&pwq->pool->lock);
                        }
                } else {
-                        spin_lock(&gcwq->lock);
+                        spin_lock(&pwq->pool->lock);
                }
        } else {
-                gcwq = get_gcwq(WORK_CPU_UNBOUND);
+                pwq = get_pwq(WORK_CPU_UNBOUND, wq);
-                spin_lock(&gcwq->lock);
+                spin_lock(&pwq->pool->lock);
        }
-        /* gcwq determined, get cwq and queue */
+        /* pwq determined, queue */
-        cwq = get_cwq(gcwq->cpu, wq);
+        trace_workqueue_queue_work(req_cpu, pwq, work);
-        trace_workqueue_queue_work(req_cpu, cwq, work);
        if (WARN_ON(!list_empty(&work->entry))) {
-                spin_unlock(&gcwq->lock);
+                spin_unlock(&pwq->pool->lock);
                return;
        }
-        cwq->nr_in_flight[cwq->work_color]++;
+        pwq->nr_in_flight[pwq->work_color]++;
-        work_flags = work_color_to_flags(cwq->work_color);
+        work_flags = work_color_to_flags(pwq->work_color);
-        if (likely(cwq->nr_active < cwq->max_active)) {
+        if (likely(pwq->nr_active < pwq->max_active)) {
                trace_workqueue_activate_work(work);
-                cwq->nr_active++;
+                pwq->nr_active++;
-                worklist = &cwq->pool->worklist;
+                worklist = &pwq->pool->worklist;
        } else {
                work_flags |= WORK_STRUCT_DELAYED;
-                worklist = &cwq->delayed_works;
+                worklist = &pwq->delayed_works;
        }
-        insert_work(cwq, work, worklist, work_flags);
+        insert_work(pwq, work, worklist, work_flags);
-        spin_unlock(&gcwq->lock);
+        spin_unlock(&pwq->pool->lock);
 }
 /**
@@ -1345,51 +1306,37 @@ EXPORT_SYMBOL_GPL(queue_work);
 void delayed_work_timer_fn(unsigned long __data)
 {
        struct delayed_work *dwork = (struct delayed_work *)__data;
-        struct cpu_workqueue_struct *cwq = get_work_cwq(&dwork->work);
        /* should have been called from irqsafe timer with irq already off */
-        __queue_work(dwork->cpu, cwq->wq, &dwork->work);
+        __queue_work(dwork->cpu, dwork->wq, &dwork->work);
 }
-EXPORT_SYMBOL_GPL(delayed_work_timer_fn);
+EXPORT_SYMBOL(delayed_work_timer_fn);
 static void __queue_delayed_work(int cpu, struct workqueue_struct *wq,
                                struct delayed_work *dwork, unsigned long delay)
 {
        struct timer_list *timer = &dwork->timer;
        struct work_struct *work = &dwork->work;
-        unsigned int lcpu;
        WARN_ON_ONCE(timer->function != delayed_work_timer_fn ||
                     timer->data != (unsigned long)dwork);
-        BUG_ON(timer_pending(timer));
+        WARN_ON_ONCE(timer_pending(timer));
-        BUG_ON(!list_empty(&work->entry));
+        WARN_ON_ONCE(!list_empty(&work->entry));
-        timer_stats_timer_set_start_info(&dwork->timer);
        /*
-         * This stores cwq for the moment, for the timer_fn.  Note that the
+         * If @delay is 0, queue @dwork->work immediately.  This is for
-         * work's gcwq is preserved to allow reentrance detection for
+         * both optimization and correctness.  The earliest @timer can
-         * delayed works.
+         * expire is on the closest next tick and delayed_work users depend
+         * on that there's no such delay when @delay is 0.
         */
-        if (!(wq->flags & WQ_UNBOUND)) {
+        if (!delay) {
-                struct global_cwq *gcwq = get_work_gcwq(work);
+                __queue_work(cpu, wq, &dwork->work);
+                return;
-                /*
-                 * If we cannot get the last gcwq from @work directly,
-                 * select the last CPU such that it avoids unnecessarily
-                 * triggering non-reentrancy check in __queue_work().
-                 */
-                lcpu = cpu;
-                if (gcwq)
-                        lcpu = gcwq->cpu;
-                if (lcpu == WORK_CPU_UNBOUND)
-                        lcpu = raw_smp_processor_id();
-        } else {
-                lcpu = WORK_CPU_UNBOUND;
        }
-        set_work_cwq(work, get_cwq(lcpu, wq), 0);
+        timer_stats_timer_set_start_info(&dwork->timer);
+        dwork->wq = wq;
        dwork->cpu = cpu;
        timer->expires = jiffies + delay;
@@ -1417,9 +1364,6 @@ bool queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
        bool ret = false;
        unsigned long flags;
-        if (!delay)
-                return queue_work_on(cpu, wq, &dwork->work);
        /* read the comment in __queue_work() */
        local_irq_save(flags);
@@ -1509,12 +1453,11 @@ EXPORT_SYMBOL_GPL(mod_delayed_work);
 * necessary.
 *
 * LOCKING:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
 static void worker_enter_idle(struct worker *worker)
 {
        struct worker_pool *pool = worker->pool;
-        struct global_cwq *gcwq = pool->gcwq;
        BUG_ON(worker->flags & WORKER_IDLE);
        BUG_ON(!list_empty(&worker->entry) &&
@@ -1532,14 +1475,14 @@ static void worker_enter_idle(struct worker *worker)
                mod_timer(&pool->idle_timer, jiffies + IDLE_WORKER_TIMEOUT);
        /*
-         * Sanity check nr_running.  Because gcwq_unbind_fn() releases
+         * Sanity check nr_running.  Because wq_unbind_fn() releases
-         * gcwq->lock between setting %WORKER_UNBOUND and zapping
+         * pool->lock between setting %WORKER_UNBOUND and zapping
         * nr_running, the warning may trigger spuriously.  Check iff
         * unbind is not in progress.
         */
-        WARN_ON_ONCE(!(gcwq->flags & GCWQ_DISASSOCIATED) &&
+        WARN_ON_ONCE(!(pool->flags & POOL_DISASSOCIATED) &&
                     pool->nr_workers == pool->nr_idle &&
-                     atomic_read(get_pool_nr_running(pool)));
+                     atomic_read(&pool->nr_running));
 }
 /**
@@ -1549,7 +1492,7 @@ static void worker_enter_idle(struct worker *worker)
 * @worker is leaving idle state.  Update stats.
 *
 * LOCKING:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
 static void worker_leave_idle(struct worker *worker)
 {
@@ -1562,7 +1505,7 @@ static void worker_leave_idle(struct worker *worker)
 }
 /**
- * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock gcwq
+ * worker_maybe_bind_and_lock - bind worker to its cpu if possible and lock pool
 * @worker: self
 *
 * Works which are scheduled while the cpu is online must at least be
@@ -1574,27 +1517,27 @@ static void worker_leave_idle(struct worker *worker)
 * themselves to the target cpu and may race with cpu going down or
 * coming online.  kthread_bind() can't be used because it may put the
 * worker to already dead cpu and set_cpus_allowed_ptr() can't be used
- * verbatim as it's best effort and blocking and gcwq may be
+ * verbatim as it's best effort and blocking and pool may be
 * [dis]associated in the meantime.
 *
- * This function tries set_cpus_allowed() and locks gcwq and verifies the
+ * This function tries set_cpus_allowed() and locks pool and verifies the
- * binding against %GCWQ_DISASSOCIATED which is set during
+ * binding against %POOL_DISASSOCIATED which is set during
 * %CPU_DOWN_PREPARE and cleared during %CPU_ONLINE, so if the worker
 * enters idle state or fetches works without dropping lock, it can
 * guarantee the scheduling requirement described in the first paragraph.
 *
 * CONTEXT:
- * Might sleep.  Called without any lock but returns with gcwq->lock
+ * Might sleep.  Called without any lock but returns with pool->lock
 * held.
 *
 * RETURNS:
- * %true if the associated gcwq is online (@worker is successfully
+ * %true if the associated pool is online (@worker is successfully
 * bound), %false if offline.
 */
 static bool worker_maybe_bind_and_lock(struct worker *worker)
-__acquires(&gcwq->lock)
+__acquires(&pool->lock)
 {
-        struct global_cwq *gcwq = worker->pool->gcwq;
+        struct worker_pool *pool = worker->pool;
        struct task_struct *task = worker->task;
        while (true) {
@@ -1602,19 +1545,19 @@ __acquires(&gcwq->lock)
                 * The following call may fail, succeed or succeed
                 * without actually migrating the task to the cpu if
                 * it races with cpu hotunplug operation.  Verify
-                 * against GCWQ_DISASSOCIATED.
+                 * against POOL_DISASSOCIATED.
                 */
-                if (!(gcwq->flags & GCWQ_DISASSOCIATED))
+                if (!(pool->flags & POOL_DISASSOCIATED))
-                        set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu));
+                        set_cpus_allowed_ptr(task, get_cpu_mask(pool->cpu));
-                spin_lock_irq(&gcwq->lock);
+                spin_lock_irq(&pool->lock);
-                if (gcwq->flags & GCWQ_DISASSOCIATED)
+                if (pool->flags & POOL_DISASSOCIATED)
                        return false;
-                if (task_cpu(task) == gcwq->cpu &&
+                if (task_cpu(task) == pool->cpu &&
                    cpumask_equal(&current->cpus_allowed,
-                                  get_cpu_mask(gcwq->cpu)))
+                                  get_cpu_mask(pool->cpu)))
                        return true;
-                spin_unlock_irq(&gcwq->lock);
+                spin_unlock_irq(&pool->lock);
                /*
                 * We've raced with CPU hot[un]plug.  Give it a breather
@@ -1633,15 +1576,13 @@ __acquires(&gcwq->lock)
 */
 static void idle_worker_rebind(struct worker *worker)
 {
-        struct global_cwq *gcwq = worker->pool->gcwq;
        /* CPU may go down again inbetween, clear UNBOUND only on success */
        if (worker_maybe_bind_and_lock(worker))
                worker_clr_flags(worker, WORKER_UNBOUND);
        /* rebind complete, become available again */
        list_add(&worker->entry, &worker->pool->idle_list);
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&worker->pool->lock);
 }
 /*
@@ -1653,19 +1594,18 @@ static void idle_worker_rebind(struct worker *worker)
 static void busy_worker_rebind_fn(struct work_struct *work)
 {
        struct worker *worker = container_of(work, struct worker, rebind_work);
-        struct global_cwq *gcwq = worker->pool->gcwq;
        if (worker_maybe_bind_and_lock(worker))
                worker_clr_flags(worker, WORKER_UNBOUND);
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&worker->pool->lock);
 }
 /**
- * rebind_workers - rebind all workers of a gcwq to the associated CPU
+ * rebind_workers - rebind all workers of a pool to the associated CPU
- * @gcwq: gcwq of interest
+ * @pool: pool of interest
 *
- * @gcwq->cpu is coming online.  Rebind all workers to the CPU.  Rebinding
+ * @pool->cpu is coming online.  Rebind all workers to the CPU.  Rebinding
 * is different for idle and busy ones.
 *
 * Idle ones will be removed from the idle_list and woken up.  They will
@@ -1683,38 +1623,31 @@ static void busy_worker_rebind_fn(struct work_struct *work)
 * including the manager will not appear on @idle_list until rebind is
 * complete, making local wake-ups safe.
 */
-static void rebind_workers(struct global_cwq *gcwq)
+static void rebind_workers(struct worker_pool *pool)
 {
-        struct worker_pool *pool;
        struct worker *worker, *n;
-        struct hlist_node *pos;
        int i;
-        lockdep_assert_held(&gcwq->lock);
+        lockdep_assert_held(&pool->assoc_mutex);
+        lockdep_assert_held(&pool->lock);
-        for_each_worker_pool(pool, gcwq)
-                lockdep_assert_held(&pool->assoc_mutex);
        /* dequeue and kick idle ones */
-        for_each_worker_pool(pool, gcwq) {
+        list_for_each_entry_safe(worker, n, &pool->idle_list, entry) {
-                list_for_each_entry_safe(worker, n, &pool->idle_list, entry) {
+                /*
-                        /*
+                 * idle workers should be off @pool->idle_list until rebind
-                         * idle workers should be off @pool->idle_list
+                 * is complete to avoid receiving premature local wake-ups.
-                         * until rebind is complete to avoid receiving
+                 */
-                         * premature local wake-ups.
+                list_del_init(&worker->entry);
-                         */
-                        list_del_init(&worker->entry);
-                        /*
+                /*
-                         * worker_thread() will see the above dequeuing
+                 * worker_thread() will see the above dequeuing and call
-                         * and call idle_worker_rebind().
+                 * idle_worker_rebind().
-                         */
+                 */
-                        wake_up_process(worker->task);
+                wake_up_process(worker->task);
-                }
        }
        /* rebind busy workers */
-        for_each_busy_worker(worker, i, pos, gcwq) {
+        for_each_busy_worker(worker, i, pool) {
                struct work_struct *rebind_work = &worker->rebind_work;
                struct workqueue_struct *wq;
@@ -1726,16 +1659,16 @@ static void rebind_workers(struct global_cwq *gcwq)
                /*
                 * wq doesn't really matter but let's keep @worker->pool
-                 * and @cwq->pool consistent for sanity.
+                 * and @pwq->pool consistent for sanity.
                 */
-                if (worker_pool_pri(worker->pool))
+                if (std_worker_pool_pri(worker->pool))
                        wq = system_highpri_wq;
                else
                        wq = system_wq;
-                insert_work(get_cwq(gcwq->cpu, wq), rebind_work,
+                insert_work(get_pwq(pool->cpu, wq), rebind_work,
-                        worker->scheduled.next,
+                            worker->scheduled.next,
-                        work_color_to_flags(WORK_NO_COLOR));
+                            work_color_to_flags(WORK_NO_COLOR));
        }
 }
@@ -1770,19 +1703,18 @@ static struct worker *alloc_worker(void)
 */
 static struct worker *create_worker(struct worker_pool *pool)
 {
-        struct global_cwq *gcwq = pool->gcwq;
+        const char *pri = std_worker_pool_pri(pool) ? "H" : "";
-        const char *pri = worker_pool_pri(pool) ? "H" : "";
        struct worker *worker = NULL;
        int id = -1;
-        spin_lock_irq(&gcwq->lock);
+        spin_lock_irq(&pool->lock);
        while (ida_get_new(&pool->worker_ida, &id)) {
-                spin_unlock_irq(&gcwq->lock);
+                spin_unlock_irq(&pool->lock);
                if (!ida_pre_get(&pool->worker_ida, GFP_KERNEL))
                        goto fail;
-                spin_lock_irq(&gcwq->lock);
+                spin_lock_irq(&pool->lock);
        }
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
        worker = alloc_worker();
        if (!worker)
@@ -1791,30 +1723,30 @@ static struct worker *create_worker(struct worker_pool *pool)
        worker->pool = pool;
        worker->id = id;
-        if (gcwq->cpu != WORK_CPU_UNBOUND)
+        if (pool->cpu != WORK_CPU_UNBOUND)
                worker->task = kthread_create_on_node(worker_thread,
-                                        worker, cpu_to_node(gcwq->cpu),
+                                        worker, cpu_to_node(pool->cpu),
-                                        "kworker/%u:%d%s", gcwq->cpu, id, pri);
+                                        "kworker/%u:%d%s", pool->cpu, id, pri);
        else
                worker->task = kthread_create(worker_thread, worker,
                                              "kworker/u:%d%s", id, pri);
        if (IS_ERR(worker->task))
                goto fail;
-        if (worker_pool_pri(pool))
+        if (std_worker_pool_pri(pool))
                set_user_nice(worker->task, HIGHPRI_NICE_LEVEL);
        /*
         * Determine CPU binding of the new worker depending on
-         * %GCWQ_DISASSOCIATED.  The caller is responsible for ensuring the
+         * %POOL_DISASSOCIATED.  The caller is responsible for ensuring the
         * flag remains stable across this function.  See the comments
         * above the flag definition for details.
         *
         * As an unbound worker may later become a regular one if CPU comes
         * online, make sure every worker has %PF_THREAD_BOUND set.
         */
-        if (!(gcwq->flags & GCWQ_DISASSOCIATED)) {
+        if (!(pool->flags & POOL_DISASSOCIATED)) {
-                kthread_bind(worker->task, gcwq->cpu);
+                kthread_bind(worker->task, pool->cpu);
        } else {
                worker->task->flags |= PF_THREAD_BOUND;
                worker->flags |= WORKER_UNBOUND;
@@ -1823,9 +1755,9 @@ static struct worker *create_worker(struct worker_pool *pool)
        return worker;
 fail:
        if (id >= 0) {
-                spin_lock_irq(&gcwq->lock);
+                spin_lock_irq(&pool->lock);
                ida_remove(&pool->worker_ida, id);
-                spin_unlock_irq(&gcwq->lock);
+                spin_unlock_irq(&pool->lock);
        }
        kfree(worker);
        return NULL;
@@ -1835,10 +1767,10 @@ fail:
 * start_worker - start a newly created worker
 * @worker: worker to start
 *
- * Make the gcwq aware of @worker and start it.
+ * Make the pool aware of @worker and start it.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
 static void start_worker(struct worker *worker)
 {
@@ -1852,15 +1784,14 @@ static void start_worker(struct worker *worker)
 * destroy_worker - destroy a workqueue worker
 * @worker: worker to be destroyed
 *
- * Destroy @worker and adjust @gcwq stats accordingly.
+ * Destroy @worker and adjust @pool stats accordingly.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock) which is released and regrabbed.
+ * spin_lock_irq(pool->lock) which is released and regrabbed.
 */
 static void destroy_worker(struct worker *worker)
 {
        struct worker_pool *pool = worker->pool;
-        struct global_cwq *gcwq = pool->gcwq;
        int id = worker->id;
        /* sanity check frenzy */
@@ -1875,21 +1806,20 @@ static void destroy_worker(struct worker *worker)
        list_del_init(&worker->entry);
        worker->flags |= WORKER_DIE;
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
        kthread_stop(worker->task);
        kfree(worker);
-        spin_lock_irq(&gcwq->lock);
+        spin_lock_irq(&pool->lock);
        ida_remove(&pool->worker_ida, id);
 }
 static void idle_worker_timeout(unsigned long __pool)
 {
        struct worker_pool *pool = (void *)__pool;
-        struct global_cwq *gcwq = pool->gcwq;
-        spin_lock_irq(&gcwq->lock);
+        spin_lock_irq(&pool->lock);
        if (too_many_workers(pool)) {
                struct worker *worker;
@@ -1908,20 +1838,20 @@ static void idle_worker_timeout(unsigned long __pool)
                }
        }
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
 }
 static bool send_mayday(struct work_struct *work)
 {
-        struct cpu_workqueue_struct *cwq = get_work_cwq(work);
+        struct pool_workqueue *pwq = get_work_pwq(work);
-        struct workqueue_struct *wq = cwq->wq;
+        struct workqueue_struct *wq = pwq->wq;
        unsigned int cpu;
        if (!(wq->flags & WQ_RESCUER))
                return false;
        /* mayday mayday mayday */
-        cpu = cwq->pool->gcwq->cpu;
+        cpu = pwq->pool->cpu;
        /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */
        if (cpu == WORK_CPU_UNBOUND)
                cpu = 0;
@@ -1930,13 +1860,12 @@ static bool send_mayday(struct work_struct *work)
        return true;
 }
-static void gcwq_mayday_timeout(unsigned long __pool)
+static void pool_mayday_timeout(unsigned long __pool)
 {
        struct worker_pool *pool = (void *)__pool;
-        struct global_cwq *gcwq = pool->gcwq;
        struct work_struct *work;
-        spin_lock_irq(&gcwq->lock);
+        spin_lock_irq(&pool->lock);
        if (need_to_create_worker(pool)) {
                /*
@@ -1949,7 +1878,7 @@ static void gcwq_mayday_timeout(unsigned long __pool)
                        send_mayday(work);
        }
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
        mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INTERVAL);
 }
@@ -1968,24 +1897,22 @@ static void gcwq_mayday_timeout(unsigned long __pool)
 * may_start_working() true.
 *
 * LOCKING:
- * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * spin_lock_irq(pool->lock) which may be released and regrabbed
 * multiple times.  Does GFP_KERNEL allocations.  Called only from
 * manager.
 *
 * RETURNS:
- * false if no action was taken and gcwq->lock stayed locked, true
+ * false if no action was taken and pool->lock stayed locked, true
 * otherwise.
 */
 static bool maybe_create_worker(struct worker_pool *pool)
-__releases(&gcwq->lock)
+__releases(&pool->lock)
-__acquires(&gcwq->lock)
+__acquires(&pool->lock)
 {
-        struct global_cwq *gcwq = pool->gcwq;
        if (!need_to_create_worker(pool))
                return false;
 restart:
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
        /* if we don't make progress in MAYDAY_INITIAL_TIMEOUT, call for help */
        mod_timer(&pool->mayday_timer, jiffies + MAYDAY_INITIAL_TIMEOUT);
@@ -1996,7 +1923,7 @@ restart:
                worker = create_worker(pool);
                if (worker) {
                        del_timer_sync(&pool->mayday_timer);
-                        spin_lock_irq(&gcwq->lock);
+                        spin_lock_irq(&pool->lock);
                        start_worker(worker);
                        BUG_ON(need_to_create_worker(pool));
                        return true;
@@ -2013,7 +1940,7 @@ restart:
        }
        del_timer_sync(&pool->mayday_timer);
-        spin_lock_irq(&gcwq->lock);
+        spin_lock_irq(&pool->lock);
        if (need_to_create_worker(pool))
                goto restart;
        return true;
@@ -2027,11 +1954,11 @@ restart:
 * IDLE_WORKER_TIMEOUT.
 *
 * LOCKING:
- * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * spin_lock_irq(pool->lock) which may be released and regrabbed
 * multiple times.  Called only from manager.
 *
 * RETURNS:
- * false if no action was taken and gcwq->lock stayed locked, true
+ * false if no action was taken and pool->lock stayed locked, true
 * otherwise.
 */
 static bool maybe_destroy_workers(struct worker_pool *pool)
@@ -2061,21 +1988,21 @@ static bool maybe_destroy_workers(struct worker_pool *pool)
 * manage_workers - manage worker pool
 * @worker: self
 *
- * Assume the manager role and manage gcwq worker pool @worker belongs
+ * Assume the manager role and manage the worker pool @worker belongs
 * to.  At any given time, there can be only zero or one manager per
- * gcwq.  The exclusion is handled automatically by this function.
+ * pool.  The exclusion is handled automatically by this function.
 *
 * The caller can safely start processing works on false return.  On
 * true return, it's guaranteed that need_to_create_worker() is false
 * and may_start_working() is true.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * spin_lock_irq(pool->lock) which may be released and regrabbed
 * multiple times.  Does GFP_KERNEL allocations.
 *
 * RETURNS:
- * false if no action was taken and gcwq->lock stayed locked, true if
+ * spin_lock_irq(pool->lock) which may be released and regrabbed
- * some action was taken.
+ * multiple times.  Does GFP_KERNEL allocations.
 */
 static bool manage_workers(struct worker *worker)
 {
@@ -2097,20 +2024,20 @@ static bool manage_workers(struct worker *worker)
         * manager against CPU hotplug.
         *
         * assoc_mutex would always be free unless CPU hotplug is in
-         * progress.  trylock first without dropping @gcwq->lock.
+         * progress.  trylock first without dropping @pool->lock.
         */
        if (unlikely(!mutex_trylock(&pool->assoc_mutex))) {
-                spin_unlock_irq(&pool->gcwq->lock);
+                spin_unlock_irq(&pool->lock);
                mutex_lock(&pool->assoc_mutex);
                /*
                 * CPU hotplug could have happened while we were waiting
                 * for assoc_mutex.  Hotplug itself can't handle us
                 * because manager isn't either on idle or busy list, and
-                 * @gcwq's state and ours could have deviated.
+                 * @pool's state and ours could have deviated.
                 *
                 * As hotplug is now excluded via assoc_mutex, we can
                 * simply try to bind.  It will succeed or fail depending
-                 * on @gcwq's current state.  Try it and adjust
+                 * on @pool's current state.  Try it and adjust
                 * %WORKER_UNBOUND accordingly.
                 */
                if (worker_maybe_bind_and_lock(worker))
@@ -2147,18 +2074,15 @@ static bool manage_workers(struct worker *worker)
 * call this function to process a work.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock) which is released and regrabbed.
+ * spin_lock_irq(pool->lock) which is released and regrabbed.
 */
 static void process_one_work(struct worker *worker, struct work_struct *work)
-__releases(&gcwq->lock)
+__releases(&pool->lock)
-__acquires(&gcwq->lock)
+__acquires(&pool->lock)
 {
-        struct cpu_workqueue_struct *cwq = get_work_cwq(work);
+        struct pool_workqueue *pwq = get_work_pwq(work);
        struct worker_pool *pool = worker->pool;
-        struct global_cwq *gcwq = pool->gcwq;
+        bool cpu_intensive = pwq->wq->flags & WQ_CPU_INTENSIVE;
-        struct hlist_head *bwh = busy_worker_head(gcwq, work);
-        bool cpu_intensive = cwq->wq->flags & WQ_CPU_INTENSIVE;
-        work_func_t f = work->func;
        int work_color;
        struct worker *collision;
 #ifdef CONFIG_LOCKDEP
@@ -2176,11 +2100,11 @@ __acquires(&gcwq->lock)
        /*
         * Ensure we're on the correct CPU.  DISASSOCIATED test is
         * necessary to avoid spurious warnings from rescuers servicing the
-         * unbound or a disassociated gcwq.
+         * unbound or a disassociated pool.
         */
        WARN_ON_ONCE(!(worker->flags & WORKER_UNBOUND) &&
-                     !(gcwq->flags & GCWQ_DISASSOCIATED) &&
+                     !(pool->flags & POOL_DISASSOCIATED) &&
-                     raw_smp_processor_id() != gcwq->cpu);
+                     raw_smp_processor_id() != pool->cpu);
        /*
         * A single work shouldn't be executed concurrently by
@@ -2188,7 +2112,7 @@ __acquires(&gcwq->lock)
         * already processing the work.  If so, defer the work to the
         * currently executing one.
         */
-        collision = __find_worker_executing_work(gcwq, bwh, work);
+        collision = find_worker_executing_work(pool, work);
        if (unlikely(collision)) {
                move_linked_works(work, &collision->scheduled, NULL);
                return;
@@ -2196,9 +2120,10 @@ __acquires(&gcwq->lock)
        /* claim and dequeue */
        debug_work_deactivate(work);
-        hlist_add_head(&worker->hentry, bwh);
+        hash_add(pool->busy_hash, &worker->hentry, (unsigned long)work);
        worker->current_work = work;
-        worker->current_cwq = cwq;
+        worker->current_func = work->func;
+        worker->current_pwq = pwq;
        work_color = get_work_color(work);
        list_del_init(&work->entry);
@@ -2211,53 +2136,55 @@ __acquires(&gcwq->lock)
                worker_set_flags(worker, WORKER_CPU_INTENSIVE, true);
        /*
-         * Unbound gcwq isn't concurrency managed and work items should be
+         * Unbound pool isn't concurrency managed and work items should be
         * executed ASAP.  Wake up another worker if necessary.
         */
        if ((worker->flags & WORKER_UNBOUND) && need_more_worker(pool))
                wake_up_worker(pool);
        /*
-         * Record the last CPU and clear PENDING which should be the last
+         * Record the last pool and clear PENDING which should be the last
-         * update to @work.  Also, do this inside @gcwq->lock so that
+         * update to @work.  Also, do this inside @pool->lock so that
         * PENDING and queued state changes happen together while IRQ is
         * disabled.
         */
-        set_work_cpu_and_clear_pending(work, gcwq->cpu);
+        set_work_pool_and_clear_pending(work, pool->id);
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
-        lock_map_acquire_read(&cwq->wq->lockdep_map);
+        lock_map_acquire_read(&pwq->wq->lockdep_map);
        lock_map_acquire(&lockdep_map);
        trace_workqueue_execute_start(work);
-        f(work);
+        worker->current_func(work);
        /*
         * While we must be careful to not use "work" after this, the trace
         * point will only record its address.
         */
        trace_workqueue_execute_end(work);
        lock_map_release(&lockdep_map);
-        lock_map_release(&cwq->wq->lockdep_map);
+        lock_map_release(&pwq->wq->lockdep_map);
        if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
                pr_err("BUG: workqueue leaked lock or atomic: %s/0x%08x/%d\n"
                       "     last function: %pf\n",
-                       current->comm, preempt_count(), task_pid_nr(current), f);
+                       current->comm, preempt_count(), task_pid_nr(current),
+                       worker->current_func);
                debug_show_held_locks(current);
                dump_stack();
        }
-        spin_lock_irq(&gcwq->lock);
+        spin_lock_irq(&pool->lock);
        /* clear cpu intensive status */
        if (unlikely(cpu_intensive))
                worker_clr_flags(worker, WORKER_CPU_INTENSIVE);
        /* we're done with it, release */
-        hlist_del_init(&worker->hentry);
+        hash_del(&worker->hentry);
        worker->current_work = NULL;
-        worker->current_cwq = NULL;
+        worker->current_func = NULL;
-        cwq_dec_nr_in_flight(cwq, work_color);
+        worker->current_pwq = NULL;
+        pwq_dec_nr_in_flight(pwq, work_color);
 }
 /**
@@ -2269,7 +2196,7 @@ __acquires(&gcwq->lock)
 * fetches a work from the top and executes it.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock) which may be released and regrabbed
+ * spin_lock_irq(pool->lock) which may be released and regrabbed
 * multiple times.
 */
 static void process_scheduled_works(struct worker *worker)
@@ -2285,8 +2212,8 @@ static void process_scheduled_works(struct worker *worker)
 * worker_thread - the worker thread function
 * @__worker: self
 *
- * The gcwq worker thread function.  There's a single dynamic pool of
+ * The worker thread function.  There are NR_CPU_WORKER_POOLS dynamic pools
- * these per each cpu.  These workers process all works regardless of
+ * of these per each cpu.  These workers process all works regardless of
 * their specific target workqueue.  The only exception is works which
 * belong to workqueues with a rescuer which will be explained in
 * rescuer_thread().
@@ -2295,16 +2222,15 @@ static int worker_thread(void *__worker)
 {
        struct worker *worker = __worker;
        struct worker_pool *pool = worker->pool;
-        struct global_cwq *gcwq = pool->gcwq;
        /* tell the scheduler that this is a workqueue worker */
        worker->task->flags |= PF_WQ_WORKER;
 woke_up:
-        spin_lock_irq(&gcwq->lock);
+        spin_lock_irq(&pool->lock);
        /* we are off idle list if destruction or rebind is requested */
        if (unlikely(list_empty(&worker->entry))) {
-                spin_unlock_irq(&gcwq->lock);
+                spin_unlock_irq(&pool->lock);
                /* if DIE is set, destruction is requested */
                if (worker->flags & WORKER_DIE) {
@@ -2363,52 +2289,61 @@ sleep:
                goto recheck;
        /*
-         * gcwq->lock is held and there's no work to process and no
+         * pool->lock is held and there's no work to process and no need to
-         * need to manage, sleep.  Workers are woken up only while
+         * manage, sleep.  Workers are woken up only while holding
-         * holding gcwq->lock or from local cpu, so setting the
+         * pool->lock or from local cpu, so setting the current state
-         * current state before releasing gcwq->lock is enough to
+         * before releasing pool->lock is enough to prevent losing any
-         * prevent losing any event.
+         * event.
         */
        worker_enter_idle(worker);
        __set_current_state(TASK_INTERRUPTIBLE);
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
        schedule();
        goto woke_up;
 }
 /**
 * rescuer_thread - the rescuer thread function
- * @__wq: the associated workqueue
+ * @__rescuer: self
 *
 * Workqueue rescuer thread function.  There's one rescuer for each
 * workqueue which has WQ_RESCUER set.
 *
- * Regular work processing on a gcwq may block trying to create a new
+ * Regular work processing on a pool may block trying to create a new
 * worker which uses GFP_KERNEL allocation which has slight chance of
 * developing into deadlock if some works currently on the same queue
 * need to be processed to satisfy the GFP_KERNEL allocation.  This is
 * the problem rescuer solves.
 *
- * When such condition is possible, the gcwq summons rescuers of all
+ * When such condition is possible, the pool summons rescuers of all
- * workqueues which have works queued on the gcwq and let them process
+ * workqueues which have works queued on the pool and let them process
 * those works so that forward progress can be guaranteed.
 *
 * This should happen rarely.
 */
-static int rescuer_thread(void *__wq)
+static int rescuer_thread(void *__rescuer)
 {
-        struct workqueue_struct *wq = __wq;
+        struct worker *rescuer = __rescuer;
-        struct worker *rescuer = wq->rescuer;
+        struct workqueue_struct *wq = rescuer->rescue_wq;
        struct list_head *scheduled = &rescuer->scheduled;
        bool is_unbound = wq->flags & WQ_UNBOUND;
        unsigned int cpu;
        set_user_nice(current, RESCUER_NICE_LEVEL);
+        /*
+         * Mark rescuer as worker too.  As WORKER_PREP is never cleared, it
+         * doesn't participate in concurrency management.
+         */
+        rescuer->task->flags |= PF_WQ_WORKER;
 repeat:
        set_current_state(TASK_INTERRUPTIBLE);
-        if (kthread_should_stop())
+        if (kthread_should_stop()) {
+                __set_current_state(TASK_RUNNING);
+                rescuer->task->flags &= ~PF_WQ_WORKER;
                return 0;
+        }
        /*
         * See whether any cpu is asking for help.  Unbounded
@@ -2416,9 +2351,8 @@ repeat:
         */
        for_each_mayday_cpu(cpu, wq->mayday_mask) {
                unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu;
-                struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq);
+                struct pool_workqueue *pwq = get_pwq(tcpu, wq);
-                struct worker_pool *pool = cwq->pool;
+                struct worker_pool *pool = pwq->pool;
-                struct global_cwq *gcwq = pool->gcwq;
                struct work_struct *work, *n;
                __set_current_state(TASK_RUNNING);
@@ -2434,22 +2368,24 @@ repeat:
                 */
                BUG_ON(!list_empty(&rescuer->scheduled));
                list_for_each_entry_safe(work, n, &pool->worklist, entry)
-                        if (get_work_cwq(work) == cwq)
+                        if (get_work_pwq(work) == pwq)
                                move_linked_works(work, scheduled, &n);
                process_scheduled_works(rescuer);
                /*
-                 * Leave this gcwq.  If keep_working() is %true, notify a
+                 * Leave this pool.  If keep_working() is %true, notify a
                 * regular worker; otherwise, we end up with 0 concurrency
                 * and stalling the execution.
                 */
                if (keep_working(pool))
                        wake_up_worker(pool);
-                spin_unlock_irq(&gcwq->lock);
+                spin_unlock_irq(&pool->lock);
        }
+        /* rescuers should never participate in concurrency management */
+        WARN_ON_ONCE(!(rescuer->flags & WORKER_NOT_RUNNING));
        schedule();
        goto repeat;
 }
@@ -2467,7 +2403,7 @@ static void wq_barrier_func(struct work_struct *work)
 /**
 * insert_wq_barrier - insert a barrier work
- * @cwq: cwq to insert barrier into
+ * @pwq: pwq to insert barrier into
 * @barr: wq_barrier to insert
 * @target: target work to attach @barr to
 * @worker: worker currently executing @target, NULL if @target is not executing
@@ -2484,12 +2420,12 @@ static void wq_barrier_func(struct work_struct *work)
 * after a work with LINKED flag set.
 *
 * Note that when @worker is non-NULL, @target may be modified
- * underneath us, so we can't reliably determine cwq from @target.
+ * underneath us, so we can't reliably determine pwq from @target.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
-static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
+static void insert_wq_barrier(struct pool_workqueue *pwq,
                              struct wq_barrier *barr,
                              struct work_struct *target, struct worker *worker)
 {
@@ -2497,7 +2433,7 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
        unsigned int linked = 0;
        /*
-         * debugobject calls are safe here even with gcwq->lock locked
+         * debugobject calls are safe here even with pool->lock locked
         * as we know for sure that this will not trigger any of the
         * checks and call back into the fixup functions where we
         * might deadlock.
@@ -2522,23 +2458,23 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
        }
        debug_work_activate(&barr->work);
-        insert_work(cwq, &barr->work, head,
+        insert_work(pwq, &barr->work, head,
                    work_color_to_flags(WORK_NO_COLOR) | linked);
 }
 /**
- * flush_workqueue_prep_cwqs - prepare cwqs for workqueue flushing
+ * flush_workqueue_prep_pwqs - prepare pwqs for workqueue flushing
 * @wq: workqueue being flushed
 * @flush_color: new flush color, < 0 for no-op
 * @work_color: new work color, < 0 for no-op
 *
- * Prepare cwqs for workqueue flushing.
+ * Prepare pwqs for workqueue flushing.
 *
- * If @flush_color is non-negative, flush_color on all cwqs should be
+ * If @flush_color is non-negative, flush_color on all pwqs should be
- * -1.  If no cwq has in-flight commands at the specified color, all
+ * -1.  If no pwq has in-flight commands at the specified color, all
- * cwq->flush_color's stay at -1 and %false is returned.  If any cwq
+ * pwq->flush_color's stay at -1 and %false is returned.  If any pwq
- * has in flight commands, its cwq->flush_color is set to
+ * has in flight commands, its pwq->flush_color is set to
- * @flush_color, @wq->nr_cwqs_to_flush is updated accordingly, cwq
+ * @flush_color, @wq->nr_pwqs_to_flush is updated accordingly, pwq
 * wakeup logic is armed and %true is returned.
 *
 * The caller should have initialized @wq->first_flusher prior to
@@ -2546,7 +2482,7 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
 * @flush_color is negative, no flush color update is done and %false
 * is returned.
 *
- * If @work_color is non-negative, all cwqs should have the same
+ * If @work_color is non-negative, all pwqs should have the same
 * work_color which is previous to @work_color and all will be
 * advanced to @work_color.
 *
@@ -2557,42 +2493,42 @@ static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
 * %true if @flush_color >= 0 and there's something to flush.  %false
 * otherwise.
 */
-static bool flush_workqueue_prep_cwqs(struct workqueue_struct *wq,
+static bool flush_workqueue_prep_pwqs(struct workqueue_struct *wq,
                                      int flush_color, int work_color)
 {
        bool wait = false;
        unsigned int cpu;
        if (flush_color >= 0) {
-                BUG_ON(atomic_read(&wq->nr_cwqs_to_flush));
+                BUG_ON(atomic_read(&wq->nr_pwqs_to_flush));
-                atomic_set(&wq->nr_cwqs_to_flush, 1);
+                atomic_set(&wq->nr_pwqs_to_flush, 1);
        }
-        for_each_cwq_cpu(cpu, wq) {
+        for_each_pwq_cpu(cpu, wq) {
-                struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                struct pool_workqueue *pwq = get_pwq(cpu, wq);
-                struct global_cwq *gcwq = cwq->pool->gcwq;
+                struct worker_pool *pool = pwq->pool;
-                spin_lock_irq(&gcwq->lock);
+                spin_lock_irq(&pool->lock);
                if (flush_color >= 0) {
-                        BUG_ON(cwq->flush_color != -1);
+                        BUG_ON(pwq->flush_color != -1);
-                        if (cwq->nr_in_flight[flush_color]) {
+                        if (pwq->nr_in_flight[flush_color]) {
-                                cwq->flush_color = flush_color;
+                                pwq->flush_color = flush_color;
-                                atomic_inc(&wq->nr_cwqs_to_flush);
+                                atomic_inc(&wq->nr_pwqs_to_flush);
                                wait = true;
                        }
                }
                if (work_color >= 0) {
-                        BUG_ON(work_color != work_next_color(cwq->work_color));
+                        BUG_ON(work_color != work_next_color(pwq->work_color));
-                        cwq->work_color = work_color;
+                        pwq->work_color = work_color;
                }
-                spin_unlock_irq(&gcwq->lock);
+                spin_unlock_irq(&pool->lock);
        }
-        if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_cwqs_to_flush))
+        if (flush_color >= 0 && atomic_dec_and_test(&wq->nr_pwqs_to_flush))
                complete(&wq->first_flusher->done);
        return wait;
@@ -2643,7 +2579,7 @@ void flush_workqueue(struct workqueue_struct *wq)
                        wq->first_flusher = &this_flusher;
-                        if (!flush_workqueue_prep_cwqs(wq, wq->flush_color,
+                        if (!flush_workqueue_prep_pwqs(wq, wq->flush_color,
                                                       wq->work_color)) {
                                /* nothing to flush, done */
                                wq->flush_color = next_color;
@@ -2654,7 +2590,7 @@ void flush_workqueue(struct workqueue_struct *wq)
                        /* wait in queue */
                        BUG_ON(wq->flush_color == this_flusher.flush_color);
                        list_add_tail(&this_flusher.list, &wq->flusher_queue);
-                        flush_workqueue_prep_cwqs(wq, -1, wq->work_color);
+                        flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
                }
        } else {
                /*
@@ -2721,7 +2657,7 @@ void flush_workqueue(struct workqueue_struct *wq)
                        list_splice_tail_init(&wq->flusher_overflow,
                                              &wq->flusher_queue);
-                        flush_workqueue_prep_cwqs(wq, -1, wq->work_color);
+                        flush_workqueue_prep_pwqs(wq, -1, wq->work_color);
                }
                if (list_empty(&wq->flusher_queue)) {
@@ -2731,7 +2667,7 @@ void flush_workqueue(struct workqueue_struct *wq)
                /*
                 * Need to flush more colors.  Make the next flusher
-                 * the new first flusher and arm cwqs.
+                 * the new first flusher and arm pwqs.
                 */
                BUG_ON(wq->flush_color == wq->work_color);
                BUG_ON(wq->flush_color != next->flush_color);
@@ -2739,7 +2675,7 @@ void flush_workqueue(struct workqueue_struct *wq)
                list_del_init(&next->list);
                wq->first_flusher = next;
-                if (flush_workqueue_prep_cwqs(wq, wq->flush_color, -1))
+                if (flush_workqueue_prep_pwqs(wq, wq->flush_color, -1))
                        break;
                /*
@@ -2782,13 +2718,13 @@ void drain_workqueue(struct workqueue_struct *wq)
 reflush:
        flush_workqueue(wq);
-        for_each_cwq_cpu(cpu, wq) {
+        for_each_pwq_cpu(cpu, wq) {
-                struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                struct pool_workqueue *pwq = get_pwq(cpu, wq);
                bool drained;
-                spin_lock_irq(&cwq->pool->gcwq->lock);
+                spin_lock_irq(&pwq->pool->lock);
-                drained = !cwq->nr_active && list_empty(&cwq->delayed_works);
+                drained = !pwq->nr_active && list_empty(&pwq->delayed_works);
-                spin_unlock_irq(&cwq->pool->gcwq->lock);
+                spin_unlock_irq(&pwq->pool->lock);
                if (drained)
                        continue;
@@ -2810,34 +2746,29 @@ EXPORT_SYMBOL_GPL(drain_workqueue);
 static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
 {
        struct worker *worker = NULL;
-        struct global_cwq *gcwq;
+        struct worker_pool *pool;
-        struct cpu_workqueue_struct *cwq;
+        struct pool_workqueue *pwq;
        might_sleep();
-        gcwq = get_work_gcwq(work);
+        pool = get_work_pool(work);
-        if (!gcwq)
+        if (!pool)
                return false;
-        spin_lock_irq(&gcwq->lock);
+        spin_lock_irq(&pool->lock);
-        if (!list_empty(&work->entry)) {
+        /* see the comment in try_to_grab_pending() with the same code */
-                /*
+        pwq = get_work_pwq(work);
-                 * See the comment near try_to_grab_pending()->smp_rmb().
+        if (pwq) {
-                 * If it was re-queued to a different gcwq under us, we
+                if (unlikely(pwq->pool != pool))
-                 * are not going to wait.
-                 */
-                smp_rmb();
-                cwq = get_work_cwq(work);
-                if (unlikely(!cwq || gcwq != cwq->pool->gcwq))
                        goto already_gone;
        } else {
-                worker = find_worker_executing_work(gcwq, work);
+                worker = find_worker_executing_work(pool, work);
                if (!worker)
                        goto already_gone;
-                cwq = worker->current_cwq;
+                pwq = worker->current_pwq;
        }
-        insert_wq_barrier(cwq, barr, work, worker);
+        insert_wq_barrier(pwq, barr, work, worker);
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
        /*
         * If @max_active is 1 or rescuer is in use, flushing another work
@@ -2845,15 +2776,15 @@ static bool start_flush_work(struct work_struct *work, struct wq_barrier *barr)
         * flusher is not running on the same workqueue by verifying write
         * access.
         */
-        if (cwq->wq->saved_max_active == 1 || cwq->wq->flags & WQ_RESCUER)
+        if (pwq->wq->saved_max_active == 1 || pwq->wq->flags & WQ_RESCUER)
-                lock_map_acquire(&cwq->wq->lockdep_map);
+                lock_map_acquire(&pwq->wq->lockdep_map);
        else
-                lock_map_acquire_read(&cwq->wq->lockdep_map);
+                lock_map_acquire_read(&pwq->wq->lockdep_map);
-        lock_map_release(&cwq->wq->lockdep_map);
+        lock_map_release(&pwq->wq->lockdep_map);
        return true;
 already_gone:
-        spin_unlock_irq(&gcwq->lock);
+        spin_unlock_irq(&pool->lock);
        return false;
 }
@@ -2949,8 +2880,7 @@ bool flush_delayed_work(struct delayed_work *dwork)
 {
        local_irq_disable();
        if (del_timer_sync(&dwork->timer))
-                __queue_work(dwork->cpu,
+                __queue_work(dwork->cpu, dwork->wq, &dwork->work);
-                             get_work_cwq(&dwork->work)->wq, &dwork->work);
        local_irq_enable();
        return flush_work(&dwork->work);
 }
@@ -2980,7 +2910,8 @@ bool cancel_delayed_work(struct delayed_work *dwork)
        if (unlikely(ret < 0))
                return false;
-        set_work_cpu_and_clear_pending(&dwork->work, work_cpu(&dwork->work));
+        set_work_pool_and_clear_pending(&dwork->work,
+                                        get_work_pool_id(&dwork->work));
        local_irq_restore(flags);
        return ret;
 }
@@ -3159,46 +3090,46 @@ int keventd_up(void)
        return system_wq != NULL;
 }
-static int alloc_cwqs(struct workqueue_struct *wq)
+static int alloc_pwqs(struct workqueue_struct *wq)
 {
        /*
-         * cwqs are forced aligned according to WORK_STRUCT_FLAG_BITS.
+         * pwqs are forced aligned according to WORK_STRUCT_FLAG_BITS.
         * Make sure that the alignment isn't lower than that of
         * unsigned long long.
         */
-        const size_t size = sizeof(struct cpu_workqueue_struct);
+        const size_t size = sizeof(struct pool_workqueue);
        const size_t align = max_t(size_t, 1 << WORK_STRUCT_FLAG_BITS,
                                   __alignof__(unsigned long long));
        if (!(wq->flags & WQ_UNBOUND))
-                wq->cpu_wq.pcpu = __alloc_percpu(size, align);
+                wq->pool_wq.pcpu = __alloc_percpu(size, align);
        else {
                void *ptr;
                /*
-                 * Allocate enough room to align cwq and put an extra
+                 * Allocate enough room to align pwq and put an extra
                 * pointer at the end pointing back to the originally
                 * allocated pointer which will be used for free.
                 */
                ptr = kzalloc(size + align + sizeof(void *), GFP_KERNEL);
                if (ptr) {
-                        wq->cpu_wq.single = PTR_ALIGN(ptr, align);
+                        wq->pool_wq.single = PTR_ALIGN(ptr, align);
-                        *(void **)(wq->cpu_wq.single + 1) = ptr;
+                        *(void **)(wq->pool_wq.single + 1) = ptr;
                }
        }
        /* just in case, make sure it's actually aligned */
-        BUG_ON(!IS_ALIGNED(wq->cpu_wq.v, align));
+        BUG_ON(!IS_ALIGNED(wq->pool_wq.v, align));
-        return wq->cpu_wq.v ? 0 : -ENOMEM;
+        return wq->pool_wq.v ? 0 : -ENOMEM;
 }
-static void free_cwqs(struct workqueue_struct *wq)
+static void free_pwqs(struct workqueue_struct *wq)
 {
        if (!(wq->flags & WQ_UNBOUND))
-                free_percpu(wq->cpu_wq.pcpu);
+                free_percpu(wq->pool_wq.pcpu);
-        else if (wq->cpu_wq.single) {
+        else if (wq->pool_wq.single) {
-                /* the pointer to free is stored right after the cwq */
+                /* the pointer to free is stored right after the pwq */
-                kfree(*(void **)(wq->cpu_wq.single + 1));
+                kfree(*(void **)(wq->pool_wq.single + 1));
        }
 }
@@ -3252,27 +3183,25 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
        wq->flags = flags;
        wq->saved_max_active = max_active;
        mutex_init(&wq->flush_mutex);
-        atomic_set(&wq->nr_cwqs_to_flush, 0);
+        atomic_set(&wq->nr_pwqs_to_flush, 0);
        INIT_LIST_HEAD(&wq->flusher_queue);
        INIT_LIST_HEAD(&wq->flusher_overflow);
        lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
        INIT_LIST_HEAD(&wq->list);
-        if (alloc_cwqs(wq) < 0)
+        if (alloc_pwqs(wq) < 0)
                goto err;
-        for_each_cwq_cpu(cpu, wq) {
+        for_each_pwq_cpu(cpu, wq) {
-                struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                struct pool_workqueue *pwq = get_pwq(cpu, wq);
-                struct global_cwq *gcwq = get_gcwq(cpu);
-                int pool_idx = (bool)(flags & WQ_HIGHPRI);
+                BUG_ON((unsigned long)pwq & WORK_STRUCT_FLAG_MASK);
+                pwq->pool = get_std_worker_pool(cpu, flags & WQ_HIGHPRI);
-                BUG_ON((unsigned long)cwq & WORK_STRUCT_FLAG_MASK);
+                pwq->wq = wq;
-                cwq->pool = &gcwq->pools[pool_idx];
+                pwq->flush_color = -1;
-                cwq->wq = wq;
+                pwq->max_active = max_active;
-                cwq->flush_color = -1;
+                INIT_LIST_HEAD(&pwq->delayed_works);
-                cwq->max_active = max_active;
-                INIT_LIST_HEAD(&cwq->delayed_works);
        }
        if (flags & WQ_RESCUER) {
@@ -3285,7 +3214,8 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
                if (!rescuer)
                        goto err;
-                rescuer->task = kthread_create(rescuer_thread, wq, "%s",
+                rescuer->rescue_wq = wq;
+                rescuer->task = kthread_create(rescuer_thread, rescuer, "%s",
                                               wq->name);
                if (IS_ERR(rescuer->task))
                        goto err;
@@ -3302,8 +3232,8 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
        spin_lock(&workqueue_lock);
        if (workqueue_freezing && wq->flags & WQ_FREEZABLE)
-                for_each_cwq_cpu(cpu, wq)
+                for_each_pwq_cpu(cpu, wq)
-                        get_cwq(cpu, wq)->max_active = 0;
+                        get_pwq(cpu, wq)->max_active = 0;
        list_add(&wq->list, &workqueues);
@@ -3312,7 +3242,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
        return wq;
 err:
        if (wq) {
-                free_cwqs(wq);
+                free_pwqs(wq);
                free_mayday_mask(wq->mayday_mask);
                kfree(wq->rescuer);
                kfree(wq);
@@ -3343,14 +3273,14 @@ void destroy_workqueue(struct workqueue_struct *wq)
        spin_unlock(&workqueue_lock);
        /* sanity check */
-        for_each_cwq_cpu(cpu, wq) {
+        for_each_pwq_cpu(cpu, wq) {
-                struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                struct pool_workqueue *pwq = get_pwq(cpu, wq);
                int i;
                for (i = 0; i < WORK_NR_COLORS; i++)
-                        BUG_ON(cwq->nr_in_flight[i]);
+                        BUG_ON(pwq->nr_in_flight[i]);
-                BUG_ON(cwq->nr_active);
+                BUG_ON(pwq->nr_active);
-                BUG_ON(!list_empty(&cwq->delayed_works));
+                BUG_ON(!list_empty(&pwq->delayed_works));
        }
        if (wq->flags & WQ_RESCUER) {
@@ -3359,29 +3289,29 @@ void destroy_workqueue(struct workqueue_struct *wq)
                kfree(wq->rescuer);
        }
-        free_cwqs(wq);
+        free_pwqs(wq);
        kfree(wq);
 }
 EXPORT_SYMBOL_GPL(destroy_workqueue);
 /**
- * cwq_set_max_active - adjust max_active of a cwq
+ * pwq_set_max_active - adjust max_active of a pwq
- * @cwq: target cpu_workqueue_struct
+ * @pwq: target pool_workqueue
 * @max_active: new max_active value.
 *
- * Set @cwq->max_active to @max_active and activate delayed works if
+ * Set @pwq->max_active to @max_active and activate delayed works if
 * increased.
 *
 * CONTEXT:
- * spin_lock_irq(gcwq->lock).
+ * spin_lock_irq(pool->lock).
 */
-static void cwq_set_max_active(struct cpu_workqueue_struct *cwq, int max_active)
+static void pwq_set_max_active(struct pool_workqueue *pwq, int max_active)
 {
-        cwq->max_active = max_active;
+        pwq->max_active = max_active;
-        while (!list_empty(&cwq->delayed_works) &&
+        while (!list_empty(&pwq->delayed_works) &&
-               cwq->nr_active < cwq->max_active)
+               pwq->nr_active < pwq->max_active)
-                cwq_activate_first_delayed(cwq);
+                pwq_activate_first_delayed(pwq);
 }
 /**
@@ -3404,16 +3334,17 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
        wq->saved_max_active = max_active;
-        for_each_cwq_cpu(cpu, wq) {
+        for_each_pwq_cpu(cpu, wq) {
-                struct global_cwq *gcwq = get_gcwq(cpu);
+                struct pool_workqueue *pwq = get_pwq(cpu, wq);
+                struct worker_pool *pool = pwq->pool;
-                spin_lock_irq(&gcwq->lock);
+                spin_lock_irq(&pool->lock);
                if (!(wq->flags & WQ_FREEZABLE) ||
-                    !(gcwq->flags & GCWQ_FREEZING))
+                    !(pool->flags & POOL_FREEZING))
-                        cwq_set_max_active(get_cwq(gcwq->cpu, wq), max_active);
+                        pwq_set_max_active(pwq, max_active);
-                spin_unlock_irq(&gcwq->lock);
+                spin_unlock_irq(&pool->lock);
        }
        spin_unlock(&workqueue_lock);
@@ -3434,57 +3365,38 @@ EXPORT_SYMBOL_GPL(workqueue_set_max_active);
 */
 bool workqueue_congested(unsigned int cpu, struct workqueue_struct *wq)
 {
-        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+        struct pool_workqueue *pwq = get_pwq(cpu, wq);
-        return !list_empty(&cwq->delayed_works);
+        return !list_empty(&pwq->delayed_works);
 }
 EXPORT_SYMBOL_GPL(workqueue_congested);
 /**
- * work_cpu - return the last known associated cpu for @work
- * @work: the work of interest
- *
- * RETURNS:
- * CPU number if @work was ever queued.  WORK_CPU_NONE otherwise.
- */
-unsigned int work_cpu(struct work_struct *work)
-{
-        struct global_cwq *gcwq = get_work_gcwq(work);
-        return gcwq ? gcwq->cpu : WORK_CPU_NONE;
-}
-EXPORT_SYMBOL_GPL(work_cpu);
-/**
 * work_busy - test whether a work is currently pending or running
 * @work: the work to be tested
 *
 * Test whether @work is currently pending or running.  There is no
 * synchronization around this function and the test result is
 * unreliable and only useful as advisory hints or for debugging.
- * Especially for reentrant wqs, the pending state might hide the
- * running state.
 *
 * RETURNS:
 * OR'd bitmask of WORK_BUSY_* bits.
 */
 unsigned int work_busy(struct work_struct *work)
 {
-        struct global_cwq *gcwq = get_work_gcwq(work);
+        struct worker_pool *pool = get_work_pool(work);
        unsigned long flags;
        unsigned int ret = 0;
-        if (!gcwq)
-                return false;
-        spin_lock_irqsave(&gcwq->lock, flags);
        if (work_pending(work))
                ret |= WORK_BUSY_PENDING;
-        if (find_worker_executing_work(gcwq, work))
-                ret |= WORK_BUSY_RUNNING;
-        spin_unlock_irqrestore(&gcwq->lock, flags);
+        if (pool) {
+                spin_lock_irqsave(&pool->lock, flags);
+                if (find_worker_executing_work(pool, work))
+                        ret |= WORK_BUSY_RUNNING;
+                spin_unlock_irqrestore(&pool->lock, flags);
+        }
        return ret;
 }
@@ -3494,86 +3406,75 @@ EXPORT_SYMBOL_GPL(work_busy);
 * CPU hotplug.
 *
 * There are two challenges in supporting CPU hotplug.  Firstly, there
- * are a lot of assumptions on strong associations among work, cwq and
+ * are a lot of assumptions on strong associations among work, pwq and
- * gcwq which make migrating pending and scheduled works very
+ * pool which make migrating pending and scheduled works very
 * difficult to implement without impacting hot paths.  Secondly,
- * gcwqs serve mix of short, long and very long running works making
+ * worker pools serve mix of short, long and very long running works making
 * blocked draining impractical.
 *
- * This is solved by allowing a gcwq to be disassociated from the CPU
+ * This is solved by allowing the pools to be disassociated from the CPU
 * running as an unbound one and allowing it to be reattached later if the
 * cpu comes back online.
 */
-/* claim manager positions of all pools */
+static void wq_unbind_fn(struct work_struct *work)
-static void gcwq_claim_assoc_and_lock(struct global_cwq *gcwq)
-{
-        struct worker_pool *pool;
-        for_each_worker_pool(pool, gcwq)
-                mutex_lock_nested(&pool->assoc_mutex, pool - gcwq->pools);
-        spin_lock_irq(&gcwq->lock);
-}
-/* release manager positions */
-static void gcwq_release_assoc_and_unlock(struct global_cwq *gcwq)
-{
-        struct worker_pool *pool;
-        spin_unlock_irq(&gcwq->lock);
-        for_each_worker_pool(pool, gcwq)
-                mutex_unlock(&pool->assoc_mutex);
-}
-static void gcwq_unbind_fn(struct work_struct *work)
 {
-        struct global_cwq *gcwq = get_gcwq(smp_processor_id());
+        int cpu = smp_processor_id();
        struct worker_pool *pool;
        struct worker *worker;
-        struct hlist_node *pos;
        int i;
-        BUG_ON(gcwq->cpu != smp_processor_id());
+        for_each_std_worker_pool(pool, cpu) {
+                BUG_ON(cpu != smp_processor_id());
-        gcwq_claim_assoc_and_lock(gcwq);
+                mutex_lock(&pool->assoc_mutex);
+                spin_lock_irq(&pool->lock);
-        /*
+                /*
-         * We've claimed all manager positions.  Make all workers unbound
+                 * We've claimed all manager positions.  Make all workers
-         * and set DISASSOCIATED.  Before this, all workers except for the
+                 * unbound and set DISASSOCIATED.  Before this, all workers
-         * ones which are still executing works from before the last CPU
+                 * except for the ones which are still executing works from
-         * down must be on the cpu.  After this, they may become diasporas.
+                 * before the last CPU down must be on the cpu.  After
-         */
+                 * this, they may become diasporas.
-        for_each_worker_pool(pool, gcwq)
+                 */
                list_for_each_entry(worker, &pool->idle_list, entry)
                        worker->flags |= WORKER_UNBOUND;
-        for_each_busy_worker(worker, i, pos, gcwq)
+                for_each_busy_worker(worker, i, pool)
-                worker->flags |= WORKER_UNBOUND;
+                        worker->flags |= WORKER_UNBOUND;
-        gcwq->flags |= GCWQ_DISASSOCIATED;
+                pool->flags |= POOL_DISASSOCIATED;
-        gcwq_release_assoc_and_unlock(gcwq);
+                spin_unlock_irq(&pool->lock);
+                mutex_unlock(&pool->assoc_mutex);
-        /*
+                /*
-         * Call schedule() so that we cross rq->lock and thus can guarantee
+                 * Call schedule() so that we cross rq->lock and thus can
-         * sched callbacks see the %WORKER_UNBOUND flag.  This is necessary
+                 * guarantee sched callbacks see the %WORKER_UNBOUND flag.
-         * as scheduler callbacks may be invoked from other cpus.
+                 * This is necessary as scheduler callbacks may be invoked
-         */
+                 * from other cpus.
-        schedule();
+                 */
+                schedule();
-        /*
+                /*
-         * Sched callbacks are disabled now.  Zap nr_running.  After this,
+                 * Sched callbacks are disabled now.  Zap nr_running.
-         * nr_running stays zero and need_more_worker() and keep_working()
+                 * After this, nr_running stays zero and need_more_worker()
-         * are always true as long as the worklist is not empty.  @gcwq now
+                 * and keep_working() are always true as long as the
-         * behaves as unbound (in terms of concurrency management) gcwq
+                 * worklist is not empty.  This pool now behaves as an
-         * which is served by workers tied to the CPU.
+                 * unbound (in terms of concurrency management) pool which
-         *
+                 * are served by workers tied to the pool.
-         * On return from this function, the current worker would trigger
+                 */
-         * unbound chain execution of pending work items if other workers
+                atomic_set(&pool->nr_running, 0);
-         * didn't already.
-         */
+                /*
-        for_each_worker_pool(pool, gcwq)
+                 * With concurrency management just turned off, a busy
-                atomic_set(get_pool_nr_running(pool), 0);
+                 * worker blocking could lead to lengthy stalls.  Kick off
+                 * unbound chain execution of currently pending work items.
+                 */
+                spin_lock_irq(&pool->lock);
+                wake_up_worker(pool);
+                spin_unlock_irq(&pool->lock);
+        }
 }
 /*
@@ -3585,12 +3486,11 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb,
                                               void *hcpu)
 {
        unsigned int cpu = (unsigned long)hcpu;
-        struct global_cwq *gcwq = get_gcwq(cpu);
        struct worker_pool *pool;
        switch (action & ~CPU_TASKS_FROZEN) {
        case CPU_UP_PREPARE:
-                for_each_worker_pool(pool, gcwq) {
+                for_each_std_worker_pool(pool, cpu) {
                        struct worker *worker;
                        if (pool->nr_workers)
@@ -3600,18 +3500,24 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb,
                        if (!worker)
                                return NOTIFY_BAD;
-                        spin_lock_irq(&gcwq->lock);
+                        spin_lock_irq(&pool->lock);
                        start_worker(worker);
-                        spin_unlock_irq(&gcwq->lock);
+                        spin_unlock_irq(&pool->lock);
                }
                break;
        case CPU_DOWN_FAILED:
        case CPU_ONLINE:
-                gcwq_claim_assoc_and_lock(gcwq);
+                for_each_std_worker_pool(pool, cpu) {
-                gcwq->flags &= ~GCWQ_DISASSOCIATED;
+                        mutex_lock(&pool->assoc_mutex);
-                rebind_workers(gcwq);
+                        spin_lock_irq(&pool->lock);
-                gcwq_release_assoc_and_unlock(gcwq);
+                        pool->flags &= ~POOL_DISASSOCIATED;
+                        rebind_workers(pool);
+                        spin_unlock_irq(&pool->lock);
+                        mutex_unlock(&pool->assoc_mutex);
+                }
                break;
        }
        return NOTIFY_OK;
@@ -3631,7 +3537,7 @@ static int __cpuinit workqueue_cpu_down_callback(struct notifier_block *nfb,
        switch (action & ~CPU_TASKS_FROZEN) {
        case CPU_DOWN_PREPARE:
                /* unbinding should happen on the local CPU */
-                INIT_WORK_ONSTACK(&unbind_work, gcwq_unbind_fn);
+                INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn);
                queue_work_on(cpu, system_highpri_wq, &unbind_work);
                flush_work(&unbind_work);
                break;
@@ -3684,10 +3590,10 @@ EXPORT_SYMBOL_GPL(work_on_cpu);
 *
 * Start freezing workqueues.  After this function returns, all freezable
 * workqueues will queue new works to their frozen_works list instead of
- * gcwq->worklist.
+ * pool->worklist.
 *
 * CONTEXT:
- * Grabs and releases workqueue_lock and gcwq->lock's.
+ * Grabs and releases workqueue_lock and pool->lock's.
 */
 void freeze_workqueues_begin(void)
 {
@@ -3698,23 +3604,26 @@ void freeze_workqueues_begin(void)
        BUG_ON(workqueue_freezing);
        workqueue_freezing = true;
-        for_each_gcwq_cpu(cpu) {
+        for_each_wq_cpu(cpu) {
-                struct global_cwq *gcwq = get_gcwq(cpu);
+                struct worker_pool *pool;
                struct workqueue_struct *wq;
-                spin_lock_irq(&gcwq->lock);
+                for_each_std_worker_pool(pool, cpu) {
+                        spin_lock_irq(&pool->lock);
-                BUG_ON(gcwq->flags & GCWQ_FREEZING);
+                        WARN_ON_ONCE(pool->flags & POOL_FREEZING);
-                gcwq->flags |= GCWQ_FREEZING;
+                        pool->flags |= POOL_FREEZING;
-                list_for_each_entry(wq, &workqueues, list) {
+                        list_for_each_entry(wq, &workqueues, list) {
-                        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                                struct pool_workqueue *pwq = get_pwq(cpu, wq);
-                        if (cwq && wq->flags & WQ_FREEZABLE)
+                                if (pwq && pwq->pool == pool &&
-                                cwq->max_active = 0;
+                                    (wq->flags & WQ_FREEZABLE))
-                }
+                                        pwq->max_active = 0;
+                        }
-                spin_unlock_irq(&gcwq->lock);
+                        spin_unlock_irq(&pool->lock);
+                }
        }
        spin_unlock(&workqueue_lock);
@@ -3742,20 +3651,20 @@ bool freeze_workqueues_busy(void)
        BUG_ON(!workqueue_freezing);
-        for_each_gcwq_cpu(cpu) {
+        for_each_wq_cpu(cpu) {
                struct workqueue_struct *wq;
                /*
                 * nr_active is monotonically decreasing.  It's safe
                 * to peek without lock.
                 */
                list_for_each_entry(wq, &workqueues, list) {
-                        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                        struct pool_workqueue *pwq = get_pwq(cpu, wq);
-                        if (!cwq || !(wq->flags & WQ_FREEZABLE))
+                        if (!pwq || !(wq->flags & WQ_FREEZABLE))
                                continue;
-                        BUG_ON(cwq->nr_active < 0);
+                        BUG_ON(pwq->nr_active < 0);
-                        if (cwq->nr_active) {
+                        if (pwq->nr_active) {
                                busy = true;
                                goto out_unlock;
                        }
@@ -3770,10 +3679,10 @@ out_unlock:
 * thaw_workqueues - thaw workqueues
 *
 * Thaw workqueues.  Normal queueing is restored and all collected
- * frozen works are transferred to their respective gcwq worklists.
+ * frozen works are transferred to their respective pool worklists.
 *
 * CONTEXT:
- * Grabs and releases workqueue_lock and gcwq->lock's.
+ * Grabs and releases workqueue_lock and pool->lock's.
 */
 void thaw_workqueues(void)
 {
@@ -3784,30 +3693,31 @@ void thaw_workqueues(void)
        if (!workqueue_freezing)
                goto out_unlock;
-        for_each_gcwq_cpu(cpu) {
+        for_each_wq_cpu(cpu) {
-                struct global_cwq *gcwq = get_gcwq(cpu);
                struct worker_pool *pool;
                struct workqueue_struct *wq;
-                spin_lock_irq(&gcwq->lock);
+                for_each_std_worker_pool(pool, cpu) {
+                        spin_lock_irq(&pool->lock);
-                BUG_ON(!(gcwq->flags & GCWQ_FREEZING));
+                        WARN_ON_ONCE(!(pool->flags & POOL_FREEZING));
-                gcwq->flags &= ~GCWQ_FREEZING;
+                        pool->flags &= ~POOL_FREEZING;
-                list_for_each_entry(wq, &workqueues, list) {
+                        list_for_each_entry(wq, &workqueues, list) {
-                        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+                                struct pool_workqueue *pwq = get_pwq(cpu, wq);
-                        if (!cwq || !(wq->flags & WQ_FREEZABLE))
+                                if (!pwq || pwq->pool != pool ||
-                                continue;
+                                    !(wq->flags & WQ_FREEZABLE))
+                                        continue;
-                        /* restore max_active and repopulate worklist */
+                                /* restore max_active and repopulate worklist */
-                        cwq_set_max_active(cwq, wq->saved_max_active);
+                                pwq_set_max_active(pwq, wq->saved_max_active);
-                }
+                        }
-                for_each_worker_pool(pool, gcwq)
                        wake_up_worker(pool);
-                spin_unlock_irq(&gcwq->lock);
+                        spin_unlock_irq(&pool->lock);
+                }
        }
        workqueue_freezing = false;
@@ -3819,60 +3729,56 @@ out_unlock:
 static int __init init_workqueues(void)
 {
        unsigned int cpu;
-        int i;
-        /* make sure we have enough bits for OFFQ CPU number */
+        /* make sure we have enough bits for OFFQ pool ID */
-        BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_CPU_SHIFT)) <
+        BUILD_BUG_ON((1LU << (BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT)) <
-                     WORK_CPU_LAST);
+                     WORK_CPU_END * NR_STD_WORKER_POOLS);
        cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP);
        hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN);
-        /* initialize gcwqs */
+        /* initialize CPU pools */
-        for_each_gcwq_cpu(cpu) {
+        for_each_wq_cpu(cpu) {
-                struct global_cwq *gcwq = get_gcwq(cpu);
                struct worker_pool *pool;
-                spin_lock_init(&gcwq->lock);
+                for_each_std_worker_pool(pool, cpu) {
-                gcwq->cpu = cpu;
+                        spin_lock_init(&pool->lock);
-                gcwq->flags |= GCWQ_DISASSOCIATED;
+                        pool->cpu = cpu;
+                        pool->flags |= POOL_DISASSOCIATED;
-                for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)
-                        INIT_HLIST_HEAD(&gcwq->busy_hash[i]);
-                for_each_worker_pool(pool, gcwq) {
-                        pool->gcwq = gcwq;
                        INIT_LIST_HEAD(&pool->worklist);
                        INIT_LIST_HEAD(&pool->idle_list);
+                        hash_init(pool->busy_hash);
                        init_timer_deferrable(&pool->idle_timer);
                        pool->idle_timer.function = idle_worker_timeout;
                        pool->idle_timer.data = (unsigned long)pool;
-                        setup_timer(&pool->mayday_timer, gcwq_mayday_timeout,
+                        setup_timer(&pool->mayday_timer, pool_mayday_timeout,
                                    (unsigned long)pool);
                        mutex_init(&pool->assoc_mutex);
                        ida_init(&pool->worker_ida);
+                        /* alloc pool ID */
+                        BUG_ON(worker_pool_assign_id(pool));
                }
        }
        /* create the initial worker */
-        for_each_online_gcwq_cpu(cpu) {
+        for_each_online_wq_cpu(cpu) {
-                struct global_cwq *gcwq = get_gcwq(cpu);
                struct worker_pool *pool;
-                if (cpu != WORK_CPU_UNBOUND)
+                for_each_std_worker_pool(pool, cpu) {
-                        gcwq->flags &= ~GCWQ_DISASSOCIATED;
-                for_each_worker_pool(pool, gcwq) {
                        struct worker *worker;
+                        if (cpu != WORK_CPU_UNBOUND)
+                                pool->flags &= ~POOL_DISASSOCIATED;
                        worker = create_worker(pool);
                        BUG_ON(!worker);
-                        spin_lock_irq(&gcwq->lock);
+                        spin_lock_irq(&pool->lock);
                        start_worker(worker);
-                        spin_unlock_irq(&gcwq->lock);
+                        spin_unlock_irq(&pool->lock);
                }
        }