workqueue: record pool ID instead of CPU in work->data when off-queue

Currently, when a work item is off-queue, work->data records the CPU
it was last on, which is used to locate the last executing instance
for non-reentrance, flushing, etc.

We're in the process of removing global_cwq and making worker_pool the
top level abstraction.  This patch makes work->data point to the pool
it was last associated with instead of CPU.

After the previous WORK_OFFQ_POOL_CPU and worker_poo->id additions,
the conversion is fairly straight-forward.  WORK_OFFQ constants and
functions are modified to record and read back pool ID instead.
worker_pool_by_id() is added to allow looking up pool from ID.
get_work_pool() replaces get_work_gcwq(), which is reimplemented using
get_work_pool().  get_work_pool_id() replaces work_cpu().

This patch shouldn't introduce any observable behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>

1 files changed, 9 insertions, 9 deletions

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index f8b35763e55f..a94e4e84e7b1 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -75,19 +75,19 @@ enum {
 
         /*
          * When a work item is off queue, its high bits point to the last
-         * cpu it was on.  Cap at 31 bits and use the highest number to
-         * indicate that no cpu is associated.
+         * pool it was on.  Cap at 31 bits and use the highest number to
+         * indicate that no pool is associated.
          */
         WORK_OFFQ_FLAG_BITS     = 1,
-        WORK_OFFQ_CPU_SHIFT     = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
-        WORK_OFFQ_LEFT          = BITS_PER_LONG - WORK_OFFQ_CPU_SHIFT,
-        WORK_OFFQ_CPU_BITS      = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
-        WORK_OFFQ_CPU_NONE      = (1LU << WORK_OFFQ_CPU_BITS) - 1,
+        WORK_OFFQ_POOL_SHIFT    = WORK_OFFQ_FLAG_BASE + WORK_OFFQ_FLAG_BITS,
+        WORK_OFFQ_LEFT          = BITS_PER_LONG - WORK_OFFQ_POOL_SHIFT,
+        WORK_OFFQ_POOL_BITS     = WORK_OFFQ_LEFT <= 31 ? WORK_OFFQ_LEFT : 31,
+        WORK_OFFQ_POOL_NONE     = (1LU << WORK_OFFQ_POOL_BITS) - 1,
 
         /* convenience constants */
         WORK_STRUCT_FLAG_MASK   = (1UL << WORK_STRUCT_FLAG_BITS) - 1,
         WORK_STRUCT_WQ_DATA_MASK = ~WORK_STRUCT_FLAG_MASK,
-        WORK_STRUCT_NO_CPU      = (unsigned long)WORK_OFFQ_CPU_NONE << WORK_OFFQ_CPU_SHIFT,
+        WORK_STRUCT_NO_POOL     = (unsigned long)WORK_OFFQ_POOL_NONE << WORK_OFFQ_POOL_SHIFT,
 
         /* bit mask for work_busy() return values */
         WORK_BUSY_PENDING       = 1 << 0,
@@ -103,9 +103,9 @@ struct work_struct {
 #endif
 };
 
-#define WORK_DATA_INIT()        ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU)
+#define WORK_DATA_INIT()        ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL)
 #define WORK_DATA_STATIC_INIT() \
-        ATOMIC_LONG_INIT(WORK_STRUCT_NO_CPU | WORK_STRUCT_STATIC)
+        ATOMIC_LONG_INIT(WORK_STRUCT_NO_POOL | WORK_STRUCT_STATIC)
 
 struct delayed_work {
         struct work_struct work;