Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (33 commits)
  lockdep: fix deadlock in lockdep_trace_alloc
  lockdep: annotate reclaim context (__GFP_NOFS), fix SLOB
  lockdep: annotate reclaim context (__GFP_NOFS), fix
  lockdep: build fix for !PROVE_LOCKING
  lockstat: warn about disabled lock debugging
  lockdep: use stringify.h
  lockdep: simplify check_prev_add_irq()
  lockdep: get_user_chars() redo
  lockdep: simplify get_user_chars()
  lockdep: add comments to mark_lock_irq()
  lockdep: remove macro usage from mark_held_locks()
  lockdep: fully reduce mark_lock_irq()
  lockdep: merge the !_READ mark_lock_irq() helpers
  lockdep: merge the _READ mark_lock_irq() helpers
  lockdep: simplify mark_lock_irq() helpers #3
  lockdep: further simplify mark_lock_irq() helpers
  lockdep: simplify the mark_lock_irq() helpers
  lockdep: split up mark_lock_irq()
  lockdep: generate usage strings
  lockdep: generate the state bit definitions
  ...

11 files changed, 597 insertions, 317 deletions

diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 06b0c3568f0b..3673a3f44d9d 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -41,6 +41,7 @@
 #include <linux/utsname.h>
 #include <linux/hash.h>
 #include <linux/ftrace.h>
+#include <linux/stringify.h>
 
 #include <asm/sections.h>
 
@@ -310,12 +311,14 @@ EXPORT_SYMBOL(lockdep_on);
 #if VERBOSE
 # define HARDIRQ_VERBOSE        1
 # define SOFTIRQ_VERBOSE        1
+# define RECLAIM_VERBOSE        1
 #else
 # define HARDIRQ_VERBOSE        0
 # define SOFTIRQ_VERBOSE        0
+# define RECLAIM_VERBOSE        0
 #endif
 
-#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
+#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
 /*
  * Quick filtering for interesting events:
  */
@@ -443,17 +446,18 @@ atomic_t nr_find_usage_backwards_recursions;
  * Locking printouts:
  */
 
+#define __USAGE(__STATE)                                                \
+        [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W",       \
+        [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W",         \
+        [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
+        [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
+
 static const char *usage_str[] =
 {
-        [LOCK_USED] =                   "initial-use ",
-        [LOCK_USED_IN_HARDIRQ] =        "in-hardirq-W",
-        [LOCK_USED_IN_SOFTIRQ] =        "in-softirq-W",
-        [LOCK_ENABLED_SOFTIRQS] =       "softirq-on-W",
-        [LOCK_ENABLED_HARDIRQS] =       "hardirq-on-W",
-        [LOCK_USED_IN_HARDIRQ_READ] =   "in-hardirq-R",
-        [LOCK_USED_IN_SOFTIRQ_READ] =   "in-softirq-R",
-        [LOCK_ENABLED_SOFTIRQS_READ] =  "softirq-on-R",
-        [LOCK_ENABLED_HARDIRQS_READ] =  "hardirq-on-R",
+#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+        [LOCK_USED] = "INITIAL USE",
 };
 
 const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
@@ -461,46 +465,45 @@ const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
         return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
 }
 
-void
-get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4)
+static inline unsigned long lock_flag(enum lock_usage_bit bit)
 {
-        *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.';
-
-        if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
-                *c1 = '+';
-        else
-                if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
-                        *c1 = '-';
+        return 1UL << bit;
+}
 
-        if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
-                *c2 = '+';
-        else
-                if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
-                        *c2 = '-';
+static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
+{
+        char c = '.';
 
-        if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
-                *c3 = '-';
-        if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) {
-                *c3 = '+';
-                if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
-                        *c3 = '?';
+        if (class->usage_mask & lock_flag(bit + 2))
+                c = '+';
+        if (class->usage_mask & lock_flag(bit)) {
+                c = '-';
+                if (class->usage_mask & lock_flag(bit + 2))
+                        c = '?';
         }
 
-        if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
-                *c4 = '-';
-        if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) {
-                *c4 = '+';
-                if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
-                        *c4 = '?';
-        }
+        return c;
+}
+
+void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
+{
+        int i = 0;
+
+#define LOCKDEP_STATE(__STATE)                                          \
+        usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE);     \
+        usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+
+        usage[i] = '\0';
 }
 
 static void print_lock_name(struct lock_class *class)
 {
-        char str[KSYM_NAME_LEN], c1, c2, c3, c4;
+        char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS];
         const char *name;
 
-        get_usage_chars(class, &c1, &c2, &c3, &c4);
+        get_usage_chars(class, usage);
 
         name = class->name;
         if (!name) {
@@ -513,7 +516,7 @@ static void print_lock_name(struct lock_class *class)
                 if (class->subclass)
                         printk("/%d", class->subclass);
         }
-        printk("){%c%c%c%c}", c1, c2, c3, c4);
+        printk("){%s}", usage);
 }
 
 static void print_lockdep_cache(struct lockdep_map *lock)
@@ -1263,9 +1266,49 @@ check_usage(struct task_struct *curr, struct held_lock *prev,
                         bit_backwards, bit_forwards, irqclass);
 }
 
-static int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
-                struct held_lock *next)
+static const char *state_names[] = {
+#define LOCKDEP_STATE(__STATE) \
+        __stringify(__STATE),
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static const char *state_rnames[] = {
+#define LOCKDEP_STATE(__STATE) \
+        __stringify(__STATE)"-READ",
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline const char *state_name(enum lock_usage_bit bit)
+{
+        return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
+}
+
+static int exclusive_bit(int new_bit)
+{
+        /*
+         * USED_IN
+         * USED_IN_READ
+         * ENABLED
+         * ENABLED_READ
+         *
+         * bit 0 - write/read
+         * bit 1 - used_in/enabled
+         * bit 2+  state
+         */
+
+        int state = new_bit & ~3;
+        int dir = new_bit & 2;
+
+        /*
+         * keep state, bit flip the direction and strip read.
+         */
+        return state | (dir ^ 2);
+}
+
+static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
+                           struct held_lock *next, enum lock_usage_bit bit)
 {
         /*
          * Prove that the new dependency does not connect a hardirq-safe
@@ -1273,38 +1316,34 @@ check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
          * the backwards-subgraph starting at <prev>, and the
          * forwards-subgraph starting at <next>:
          */
-        if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
-                                        LOCK_ENABLED_HARDIRQS, "hard"))
+        if (!check_usage(curr, prev, next, bit,
+                           exclusive_bit(bit), state_name(bit)))
                 return 0;
 
+        bit++; /* _READ */
+
         /*
          * Prove that the new dependency does not connect a hardirq-safe-read
          * lock with a hardirq-unsafe lock - to achieve this we search
          * the backwards-subgraph starting at <prev>, and the
          * forwards-subgraph starting at <next>:
          */
-        if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
-                                        LOCK_ENABLED_HARDIRQS, "hard-read"))
+        if (!check_usage(curr, prev, next, bit,
+                           exclusive_bit(bit), state_name(bit)))
                 return 0;
 
-        /*
-         * Prove that the new dependency does not connect a softirq-safe
-         * lock with a softirq-unsafe lock - to achieve this we search
-         * the backwards-subgraph starting at <prev>, and the
-         * forwards-subgraph starting at <next>:
-         */
-        if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
-                                        LOCK_ENABLED_SOFTIRQS, "soft"))
-                return 0;
-        /*
-         * Prove that the new dependency does not connect a softirq-safe-read
-         * lock with a softirq-unsafe lock - to achieve this we search
-         * the backwards-subgraph starting at <prev>, and the
-         * forwards-subgraph starting at <next>:
-         */
-        if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
-                                        LOCK_ENABLED_SOFTIRQS, "soft"))
+        return 1;
+}
+
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+                struct held_lock *next)
+{
+#define LOCKDEP_STATE(__STATE)                                          \
+        if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
                 return 0;
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
 
         return 1;
 }
@@ -1933,7 +1972,7 @@ void print_irqtrace_events(struct task_struct *curr)
         print_ip_sym(curr->softirq_disable_ip);
 }
 
-static int hardirq_verbose(struct lock_class *class)
+static int HARDIRQ_verbose(struct lock_class *class)
 {
 #if HARDIRQ_VERBOSE
         return class_filter(class);
@@ -1941,7 +1980,7 @@ static int hardirq_verbose(struct lock_class *class)
         return 0;
 }
 
-static int softirq_verbose(struct lock_class *class)
+static int SOFTIRQ_verbose(struct lock_class *class)
 {
 #if SOFTIRQ_VERBOSE
         return class_filter(class);
@@ -1949,185 +1988,94 @@ static int softirq_verbose(struct lock_class *class)
         return 0;
 }
 
+static int RECLAIM_FS_verbose(struct lock_class *class)
+{
+#if RECLAIM_VERBOSE
+        return class_filter(class);
+#endif
+        return 0;
+}
+
 #define STRICT_READ_CHECKS      1
 
-static int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
-                enum lock_usage_bit new_bit)
+static int (*state_verbose_f[])(struct lock_class *class) = {
+#define LOCKDEP_STATE(__STATE) \
+        __STATE##_verbose,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
+static inline int state_verbose(enum lock_usage_bit bit,
+                                struct lock_class *class)
 {
-        int ret = 1;
+        return state_verbose_f[bit >> 2](class);
+}
 
-        switch(new_bit) {
-        case LOCK_USED_IN_HARDIRQ:
-                if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
-                        return 0;
-                if (!valid_state(curr, this, new_bit,
-                                 LOCK_ENABLED_HARDIRQS_READ))
-                        return 0;
-                /*
-                 * just marked it hardirq-safe, check that this lock
-                 * took no hardirq-unsafe lock in the past:
-                 */
-                if (!check_usage_forwards(curr, this,
-                                          LOCK_ENABLED_HARDIRQS, "hard"))
-                        return 0;
-#if STRICT_READ_CHECKS
-                /*
-                 * just marked it hardirq-safe, check that this lock
-                 * took no hardirq-unsafe-read lock in the past:
-                 */
-                if (!check_usage_forwards(curr, this,
-                                LOCK_ENABLED_HARDIRQS_READ, "hard-read"))
-                        return 0;
-#endif
-                if (hardirq_verbose(hlock_class(this)))
-                        ret = 2;
-                break;
-        case LOCK_USED_IN_SOFTIRQ:
-                if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
-                        return 0;
-                if (!valid_state(curr, this, new_bit,
-                                 LOCK_ENABLED_SOFTIRQS_READ))
-                        return 0;
-                /*
-                 * just marked it softirq-safe, check that this lock
-                 * took no softirq-unsafe lock in the past:
-                 */
-                if (!check_usage_forwards(curr, this,
-                                          LOCK_ENABLED_SOFTIRQS, "soft"))
-                        return 0;
-#if STRICT_READ_CHECKS
-                /*
-                 * just marked it softirq-safe, check that this lock
-                 * took no softirq-unsafe-read lock in the past:
-                 */
-                if (!check_usage_forwards(curr, this,
-                                LOCK_ENABLED_SOFTIRQS_READ, "soft-read"))
-                        return 0;
-#endif
-                if (softirq_verbose(hlock_class(this)))
-                        ret = 2;
-                break;
-        case LOCK_USED_IN_HARDIRQ_READ:
-                if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
-                        return 0;
-                /*
-                 * just marked it hardirq-read-safe, check that this lock
-                 * took no hardirq-unsafe lock in the past:
-                 */
-                if (!check_usage_forwards(curr, this,
-                                          LOCK_ENABLED_HARDIRQS, "hard"))
-                        return 0;
-                if (hardirq_verbose(hlock_class(this)))
-                        ret = 2;
-                break;
-        case LOCK_USED_IN_SOFTIRQ_READ:
-                if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
-                        return 0;
-                /*
-                 * just marked it softirq-read-safe, check that this lock
-                 * took no softirq-unsafe lock in the past:
-                 */
-                if (!check_usage_forwards(curr, this,
-                                          LOCK_ENABLED_SOFTIRQS, "soft"))
-                        return 0;
-                if (softirq_verbose(hlock_class(this)))
-                        ret = 2;
-                break;
-        case LOCK_ENABLED_HARDIRQS:
-                if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
-                        return 0;
-                if (!valid_state(curr, this, new_bit,
-                                 LOCK_USED_IN_HARDIRQ_READ))
-                        return 0;
-                /*
-                 * just marked it hardirq-unsafe, check that no hardirq-safe
-                 * lock in the system ever took it in the past:
-                 */
-                if (!check_usage_backwards(curr, this,
-                                           LOCK_USED_IN_HARDIRQ, "hard"))
-                        return 0;
-#if STRICT_READ_CHECKS
-                /*
-                 * just marked it hardirq-unsafe, check that no
-                 * hardirq-safe-read lock in the system ever took
-                 * it in the past:
-                 */
-                if (!check_usage_backwards(curr, this,
-                                   LOCK_USED_IN_HARDIRQ_READ, "hard-read"))
-                        return 0;
-#endif
-                if (hardirq_verbose(hlock_class(this)))
-                        ret = 2;
-                break;
-        case LOCK_ENABLED_SOFTIRQS:
-                if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
-                        return 0;
-                if (!valid_state(curr, this, new_bit,
-                                 LOCK_USED_IN_SOFTIRQ_READ))
-                        return 0;
-                /*
-                 * just marked it softirq-unsafe, check that no softirq-safe
-                 * lock in the system ever took it in the past:
-                 */
-                if (!check_usage_backwards(curr, this,
-                                           LOCK_USED_IN_SOFTIRQ, "soft"))
-                        return 0;
-#if STRICT_READ_CHECKS
-                /*
-                 * just marked it softirq-unsafe, check that no
-                 * softirq-safe-read lock in the system ever took
-                 * it in the past:
-                 */
-                if (!check_usage_backwards(curr, this,
-                                   LOCK_USED_IN_SOFTIRQ_READ, "soft-read"))
-                        return 0;
-#endif
-                if (softirq_verbose(hlock_class(this)))
-                        ret = 2;
-                break;
-        case LOCK_ENABLED_HARDIRQS_READ:
-                if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
-                        return 0;
-#if STRICT_READ_CHECKS
-                /*
-                 * just marked it hardirq-read-unsafe, check that no
-                 * hardirq-safe lock in the system ever took it in the past:
-                 */
-                if (!check_usage_backwards(curr, this,
-                                           LOCK_USED_IN_HARDIRQ, "hard"))
-                        return 0;
-#endif
-                if (hardirq_verbose(hlock_class(this)))
-                        ret = 2;
-                break;
-        case LOCK_ENABLED_SOFTIRQS_READ:
-                if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
+typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
+                             enum lock_usage_bit bit, const char *name);
+
+static int
+mark_lock_irq(struct task_struct *curr, struct held_lock *this, int new_bit)
+{
+        int excl_bit = exclusive_bit(new_bit);
+        int read = new_bit & 1;
+        int dir = new_bit & 2;
+
+        /*
+         * mark USED_IN has to look forwards -- to ensure no dependency
+         * has ENABLED state, which would allow recursion deadlocks.
+         *
+         * mark ENABLED has to look backwards -- to ensure no dependee
+         * has USED_IN state, which, again, would allow  recursion deadlocks.
+         */
+        check_usage_f usage = dir ?
+                check_usage_backwards : check_usage_forwards;
+
+        /*
+         * Validate that this particular lock does not have conflicting
+         * usage states.
+         */
+        if (!valid_state(curr, this, new_bit, excl_bit))
+                return 0;
+
+        /*
+         * Validate that the lock dependencies don't have conflicting usage
+         * states.
+         */
+        if ((!read || !dir || STRICT_READ_CHECKS) &&
+                        !usage(curr, this, excl_bit, state_name(new_bit)))
+                return 0;
+
+        /*
+         * Check for read in write conflicts
+         */
+        if (!read) {
+                if (!valid_state(curr, this, new_bit, excl_bit + 1))
                         return 0;
-#if STRICT_READ_CHECKS
-                /*
-                 * just marked it softirq-read-unsafe, check that no
-                 * softirq-safe lock in the system ever took it in the past:
-                 */
-                if (!check_usage_backwards(curr, this,
-                                           LOCK_USED_IN_SOFTIRQ, "soft"))
+
+                if (STRICT_READ_CHECKS &&
+                        !usage(curr, this, excl_bit + 1,
+                                state_name(new_bit + 1)))
                         return 0;
-#endif
-                if (softirq_verbose(hlock_class(this)))
-                        ret = 2;
-                break;
-        default:
-                WARN_ON(1);
-                break;
         }
 
-        return ret;
+        if (state_verbose(new_bit, hlock_class(this)))
+                return 2;
+
+        return 1;
 }
 
+enum mark_type {
+#define LOCKDEP_STATE(__STATE)  __STATE,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+};
+
 /*
  * Mark all held locks with a usage bit:
  */
 static int
-mark_held_locks(struct task_struct *curr, int hardirq)
+mark_held_locks(struct task_struct *curr, enum mark_type mark)
 {
         enum lock_usage_bit usage_bit;
         struct held_lock *hlock;
@@ -2136,17 +2084,12 @@ mark_held_locks(struct task_struct *curr, int hardirq)
         for (i = 0; i < curr->lockdep_depth; i++) {
                 hlock = curr->held_locks + i;
 
-                if (hardirq) {
-                        if (hlock->read)
-                                usage_bit = LOCK_ENABLED_HARDIRQS_READ;
-                        else
-                                usage_bit = LOCK_ENABLED_HARDIRQS;
-                } else {
-                        if (hlock->read)
-                                usage_bit = LOCK_ENABLED_SOFTIRQS_READ;
-                        else
-                                usage_bit = LOCK_ENABLED_SOFTIRQS;
-                }
+                usage_bit = 2 + (mark << 2); /* ENABLED */
+                if (hlock->read)
+                        usage_bit += 1; /* READ */
+
+                BUG_ON(usage_bit >= LOCK_USAGE_STATES);
+
                 if (!mark_lock(curr, hlock, usage_bit))
                         return 0;
         }
@@ -2200,7 +2143,7 @@ void trace_hardirqs_on_caller(unsigned long ip)
          * We are going to turn hardirqs on, so set the
          * usage bit for all held locks:
          */
-        if (!mark_held_locks(curr, 1))
+        if (!mark_held_locks(curr, HARDIRQ))
                 return;
         /*
          * If we have softirqs enabled, then set the usage
@@ -2208,7 +2151,7 @@ void trace_hardirqs_on_caller(unsigned long ip)
          * this bit from being set before)
          */
         if (curr->softirqs_enabled)
-                if (!mark_held_locks(curr, 0))
+                if (!mark_held_locks(curr, SOFTIRQ))
                         return;
 
         curr->hardirq_enable_ip = ip;
@@ -2288,7 +2231,7 @@ void trace_softirqs_on(unsigned long ip)
          * enabled too:
          */
         if (curr->hardirqs_enabled)
-                mark_held_locks(curr, 0);
+                mark_held_locks(curr, SOFTIRQ);
 }
 
 /*
@@ -2317,6 +2260,48 @@ void trace_softirqs_off(unsigned long ip)
                 debug_atomic_inc(&redundant_softirqs_off);
 }
 
+static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
+{
+        struct task_struct *curr = current;
+
+        if (unlikely(!debug_locks))
+                return;
+
+        /* no reclaim without waiting on it */
+        if (!(gfp_mask & __GFP_WAIT))
+                return;
+
+        /* this guy won't enter reclaim */
+        if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
+                return;
+
+        /* We're only interested __GFP_FS allocations for now */
+        if (!(gfp_mask & __GFP_FS))
+                return;
+
+        if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
+                return;
+
+        mark_held_locks(curr, RECLAIM_FS);
+}
+
+static void check_flags(unsigned long flags);
+
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+        unsigned long flags;
+
+        if (unlikely(current->lockdep_recursion))
+                return;
+
+        raw_local_irq_save(flags);
+        check_flags(flags);
+        current->lockdep_recursion = 1;
+        __lockdep_trace_alloc(gfp_mask, flags);
+        current->lockdep_recursion = 0;
+        raw_local_irq_restore(flags);
+}
+
 static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
 {
         /*
@@ -2345,19 +2330,35 @@ static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
         if (!hlock->hardirqs_off) {
                 if (hlock->read) {
                         if (!mark_lock(curr, hlock,
-                                        LOCK_ENABLED_HARDIRQS_READ))
+                                        LOCK_ENABLED_HARDIRQ_READ))
                                 return 0;
                         if (curr->softirqs_enabled)
                                 if (!mark_lock(curr, hlock,
-                                                LOCK_ENABLED_SOFTIRQS_READ))
+                                                LOCK_ENABLED_SOFTIRQ_READ))
                                         return 0;
                 } else {
                         if (!mark_lock(curr, hlock,
-                                        LOCK_ENABLED_HARDIRQS))
+                                        LOCK_ENABLED_HARDIRQ))
                                 return 0;
                         if (curr->softirqs_enabled)
                                 if (!mark_lock(curr, hlock,
-                                                LOCK_ENABLED_SOFTIRQS))
+                                                LOCK_ENABLED_SOFTIRQ))
+                                        return 0;
+                }
+        }
+
+        /*
+         * We reuse the irq context infrastructure more broadly as a general
+         * context checking code. This tests GFP_FS recursion (a lock taken
+         * during reclaim for a GFP_FS allocation is held over a GFP_FS
+         * allocation).
+         */
+        if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
+                if (hlock->read) {
+                        if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
+                                        return 0;
+                } else {
+                        if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
                                         return 0;
                 }
         }
@@ -2412,6 +2413,10 @@ static inline int separate_irq_context(struct task_struct *curr,
         return 0;
 }
 
+void lockdep_trace_alloc(gfp_t gfp_mask)
+{
+}
+
 #endif
 
 /*
@@ -2445,14 +2450,13 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
                 return 0;
 
         switch (new_bit) {
-        case LOCK_USED_IN_HARDIRQ:
-        case LOCK_USED_IN_SOFTIRQ:
-        case LOCK_USED_IN_HARDIRQ_READ:
-        case LOCK_USED_IN_SOFTIRQ_READ:
-        case LOCK_ENABLED_HARDIRQS:
-        case LOCK_ENABLED_SOFTIRQS:
-        case LOCK_ENABLED_HARDIRQS_READ:
-        case LOCK_ENABLED_SOFTIRQS_READ:
+#define LOCKDEP_STATE(__STATE)                  \
+        case LOCK_USED_IN_##__STATE:            \
+        case LOCK_USED_IN_##__STATE##_READ:     \
+        case LOCK_ENABLED_##__STATE:            \
+        case LOCK_ENABLED_##__STATE##_READ:
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
                 ret = mark_lock_irq(curr, this, new_bit);
                 if (!ret)
                         return 0;
@@ -2966,6 +2970,16 @@ void lock_release(struct lockdep_map *lock, int nested,
 }
 EXPORT_SYMBOL_GPL(lock_release);
 
+void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
+{
+        current->lockdep_reclaim_gfp = gfp_mask;
+}
+
+void lockdep_clear_current_reclaim_state(void)
+{
+        current->lockdep_reclaim_gfp = 0;
+}
+
 #ifdef CONFIG_LOCK_STAT
 static int
 print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h
index 56b196932c08..a2cc7e9a6e84 100644
--- a/kernel/lockdep_internals.h
+++ b/kernel/lockdep_internals.h
@@ -7,6 +7,45 @@
  */
 
 /*
+ * Lock-class usage-state bits:
+ */
+enum lock_usage_bit {
+#define LOCKDEP_STATE(__STATE)          \
+        LOCK_USED_IN_##__STATE,         \
+        LOCK_USED_IN_##__STATE##_READ,  \
+        LOCK_ENABLED_##__STATE,         \
+        LOCK_ENABLED_##__STATE##_READ,
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+        LOCK_USED,
+        LOCK_USAGE_STATES
+};
+
+/*
+ * Usage-state bitmasks:
+ */
+#define __LOCKF(__STATE)        LOCKF_##__STATE = (1 << LOCK_##__STATE),
+
+enum {
+#define LOCKDEP_STATE(__STATE)                                          \
+        __LOCKF(USED_IN_##__STATE)                                      \
+        __LOCKF(USED_IN_##__STATE##_READ)                               \
+        __LOCKF(ENABLED_##__STATE)                                      \
+        __LOCKF(ENABLED_##__STATE##_READ)
+#include "lockdep_states.h"
+#undef LOCKDEP_STATE
+        __LOCKF(USED)
+};
+
+#define LOCKF_ENABLED_IRQ (LOCKF_ENABLED_HARDIRQ | LOCKF_ENABLED_SOFTIRQ)
+#define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
+
+#define LOCKF_ENABLED_IRQ_READ \
+                (LOCKF_ENABLED_HARDIRQ_READ | LOCKF_ENABLED_SOFTIRQ_READ)
+#define LOCKF_USED_IN_IRQ_READ \
+                (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
+
+/*
  * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
  * we track.
  *
@@ -31,8 +70,10 @@
 extern struct list_head all_lock_classes;
 extern struct lock_chain lock_chains[];
 
-extern void
-get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4);
+#define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2)
+
+extern void get_usage_chars(struct lock_class *class,
+                            char usage[LOCK_USAGE_CHARS]);
 
 extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
 
diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c
index 13716b813896..d7135aa2d2c4 100644
--- a/kernel/lockdep_proc.c
+++ b/kernel/lockdep_proc.c
@@ -84,7 +84,7 @@ static int l_show(struct seq_file *m, void *v)
 {
         struct lock_class *class = v;
         struct lock_list *entry;
-        char c1, c2, c3, c4;
+        char usage[LOCK_USAGE_CHARS];
 
         if (v == SEQ_START_TOKEN) {
                 seq_printf(m, "all lock classes:\n");
@@ -100,8 +100,8 @@ static int l_show(struct seq_file *m, void *v)
         seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
 #endif
 
-        get_usage_chars(class, &c1, &c2, &c3, &c4);
-        seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
+        get_usage_chars(class, usage);
+        seq_printf(m, " %s", usage);
 
         seq_printf(m, ": ");
         print_name(m, class);
@@ -300,27 +300,27 @@ static int lockdep_stats_show(struct seq_file *m, void *v)
                         nr_uncategorized++;
                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
                         nr_irq_safe++;
-                if (class->usage_mask & LOCKF_ENABLED_IRQS)
+                if (class->usage_mask & LOCKF_ENABLED_IRQ)
                         nr_irq_unsafe++;
                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
                         nr_softirq_safe++;
-                if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
+                if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
                         nr_softirq_unsafe++;
                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
                         nr_hardirq_safe++;
-                if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
+                if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
                         nr_hardirq_unsafe++;
                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
                         nr_irq_read_safe++;
-                if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
+                if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
                         nr_irq_read_unsafe++;
                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
                         nr_softirq_read_safe++;
-                if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
+                if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
                         nr_softirq_read_unsafe++;
                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
                         nr_hardirq_read_safe++;
-                if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
+                if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
                         nr_hardirq_read_unsafe++;
 
 #ifdef CONFIG_PROVE_LOCKING
@@ -601,6 +601,10 @@ static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 static void seq_header(struct seq_file *m)
 {
         seq_printf(m, "lock_stat version 0.3\n");
+
+        if (unlikely(!debug_locks))
+                seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
+
         seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
                         "%14s %14s\n",
diff --git a/kernel/lockdep_states.h b/kernel/lockdep_states.h
new file mode 100644
index 000000000000..995b0cc2b84c
--- /dev/null
+++ b/kernel/lockdep_states.h
@@ -0,0 +1,9 @@
+/*
+ * Lockdep states,
+ *
+ * please update XXX_LOCK_USAGE_STATES in include/linux/lockdep.h whenever
+ * you add one, or come up with a nice dynamic solution.
+ */
+LOCKDEP_STATE(HARDIRQ)
+LOCKDEP_STATE(SOFTIRQ)
+LOCKDEP_STATE(RECLAIM_FS)
diff --git a/kernel/mutex-debug.c b/kernel/mutex-debug.c
index 1d94160eb532..50d022e5a560 100644
--- a/kernel/mutex-debug.c
+++ b/kernel/mutex-debug.c
@@ -26,11 +26,6 @@
 /*
  * Must be called with lock->wait_lock held.
  */
-void debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner)
-{
-        lock->owner = new_owner;
-}
-
 void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
 {
         memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
@@ -59,7 +54,6 @@ void debug_mutex_add_waiter(struct mutex *lock, struct mutex_waiter *waiter,
 
         /* Mark the current thread as blocked on the lock: */
         ti->task->blocked_on = waiter;
-        waiter->lock = lock;
 }
 
 void mutex_remove_waiter(struct mutex *lock, struct mutex_waiter *waiter,
@@ -82,7 +76,7 @@ void debug_mutex_unlock(struct mutex *lock)
         DEBUG_LOCKS_WARN_ON(lock->magic != lock);
         DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
         DEBUG_LOCKS_WARN_ON(!lock->wait_list.prev && !lock->wait_list.next);
-        DEBUG_LOCKS_WARN_ON(lock->owner != current_thread_info());
+        mutex_clear_owner(lock);
 }
 
 void debug_mutex_init(struct mutex *lock, const char *name,
@@ -95,7 +89,6 @@ void debug_mutex_init(struct mutex *lock, const char *name,
         debug_check_no_locks_freed((void *)lock, sizeof(*lock));
         lockdep_init_map(&lock->dep_map, name, key, 0);
 #endif
-        lock->owner = NULL;
         lock->magic = lock;
 }
 
diff --git a/kernel/mutex-debug.h b/kernel/mutex-debug.h
index babfbdfc534b..6b2d735846a5 100644
--- a/kernel/mutex-debug.h
+++ b/kernel/mutex-debug.h
@@ -13,14 +13,6 @@
 /*
  * This must be called with lock->wait_lock held.
  */
-extern void
-debug_mutex_set_owner(struct mutex *lock, struct thread_info *new_owner);
-
-static inline void debug_mutex_clear_owner(struct mutex *lock)
-{
-        lock->owner = NULL;
-}
-
 extern void debug_mutex_lock_common(struct mutex *lock,
                                     struct mutex_waiter *waiter);
 extern void debug_mutex_wake_waiter(struct mutex *lock,
@@ -35,6 +27,16 @@ extern void debug_mutex_unlock(struct mutex *lock);
 extern void debug_mutex_init(struct mutex *lock, const char *name,
                              struct lock_class_key *key);
 
+static inline void mutex_set_owner(struct mutex *lock)
+{
+        lock->owner = current_thread_info();
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+        lock->owner = NULL;
+}
+
 #define spin_lock_mutex(lock, flags)                    \
         do {                                            \
                 struct mutex *l = container_of(lock, struct mutex, wait_lock); \
diff --git a/kernel/mutex.c b/kernel/mutex.c
index 4f45d4b658ef..5d79781394a3 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -10,6 +10,11 @@
  * Many thanks to Arjan van de Ven, Thomas Gleixner, Steven Rostedt and
  * David Howells for suggestions and improvements.
  *
+ *  - Adaptive spinning for mutexes by Peter Zijlstra. (Ported to mainline
+ *    from the -rt tree, where it was originally implemented for rtmutexes
+ *    by Steven Rostedt, based on work by Gregory Haskins, Peter Morreale
+ *    and Sven Dietrich.
+ *
  * Also see Documentation/mutex-design.txt.
  */
 #include <linux/mutex.h>
@@ -46,6 +51,7 @@ __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key)
         atomic_set(&lock->count, 1);
         spin_lock_init(&lock->wait_lock);
         INIT_LIST_HEAD(&lock->wait_list);
+        mutex_clear_owner(lock);
 
         debug_mutex_init(lock, name, key);
 }
@@ -91,6 +97,7 @@ void inline __sched mutex_lock(struct mutex *lock)
          * 'unlocked' into 'locked' state.
          */
         __mutex_fastpath_lock(&lock->count, __mutex_lock_slowpath);
+        mutex_set_owner(lock);
 }
 
 EXPORT_SYMBOL(mutex_lock);
@@ -115,6 +122,14 @@ void __sched mutex_unlock(struct mutex *lock)
          * The unlocking fastpath is the 0->1 transition from 'locked'
          * into 'unlocked' state:
          */
+#ifndef CONFIG_DEBUG_MUTEXES
+        /*
+         * When debugging is enabled we must not clear the owner before time,
+         * the slow path will always be taken, and that clears the owner field
+         * after verifying that it was indeed current.
+         */
+        mutex_clear_owner(lock);
+#endif
         __mutex_fastpath_unlock(&lock->count, __mutex_unlock_slowpath);
 }
 
@@ -129,21 +144,75 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
 {
         struct task_struct *task = current;
         struct mutex_waiter waiter;
-        unsigned int old_val;
         unsigned long flags;
 
+        preempt_disable();
+        mutex_acquire(&lock->dep_map, subclass, 0, ip);
+#if defined(CONFIG_SMP) && !defined(CONFIG_DEBUG_MUTEXES)
+        /*
+         * Optimistic spinning.
+         *
+         * We try to spin for acquisition when we find that there are no
+         * pending waiters and the lock owner is currently running on a
+         * (different) CPU.
+         *
+         * The rationale is that if the lock owner is running, it is likely to
+         * release the lock soon.
+         *
+         * Since this needs the lock owner, and this mutex implementation
+         * doesn't track the owner atomically in the lock field, we need to
+         * track it non-atomically.
+         *
+         * We can't do this for DEBUG_MUTEXES because that relies on wait_lock
+         * to serialize everything.
+         */
+
+        for (;;) {
+                struct thread_info *owner;
+
+                /*
+                 * If there's an owner, wait for it to either
+                 * release the lock or go to sleep.
+                 */
+                owner = ACCESS_ONCE(lock->owner);
+                if (owner && !mutex_spin_on_owner(lock, owner))
+                        break;
+
+                if (atomic_cmpxchg(&lock->count, 1, 0) == 1) {
+                        lock_acquired(&lock->dep_map, ip);
+                        mutex_set_owner(lock);
+                        preempt_enable();
+                        return 0;
+                }
+
+                /*
+                 * When there's no owner, we might have preempted between the
+                 * owner acquiring the lock and setting the owner field. If
+                 * we're an RT task that will live-lock because we won't let
+                 * the owner complete.
+                 */
+                if (!owner && (need_resched() || rt_task(task)))
+                        break;
+
+                /*
+                 * The cpu_relax() call is a compiler barrier which forces
+                 * everything in this loop to be re-loaded. We don't need
+                 * memory barriers as we'll eventually observe the right
+                 * values at the cost of a few extra spins.
+                 */
+                cpu_relax();
+        }
+#endif
         spin_lock_mutex(&lock->wait_lock, flags);
 
         debug_mutex_lock_common(lock, &waiter);
-        mutex_acquire(&lock->dep_map, subclass, 0, ip);
         debug_mutex_add_waiter(lock, &waiter, task_thread_info(task));
 
         /* add waiting tasks to the end of the waitqueue (FIFO): */
         list_add_tail(&waiter.list, &lock->wait_list);
         waiter.task = task;
 
-        old_val = atomic_xchg(&lock->count, -1);
-        if (old_val == 1)
+        if (atomic_xchg(&lock->count, -1) == 1)
                 goto done;
 
         lock_contended(&lock->dep_map, ip);
@@ -158,8 +227,7 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
                  * that when we release the lock, we properly wake up the
                  * other waiters:
                  */
-                old_val = atomic_xchg(&lock->count, -1);
-                if (old_val == 1)
+                if (atomic_xchg(&lock->count, -1) == 1)
                         break;
 
                 /*
@@ -173,21 +241,22 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
                         spin_unlock_mutex(&lock->wait_lock, flags);
 
                         debug_mutex_free_waiter(&waiter);
+                        preempt_enable();
                         return -EINTR;
                 }
                 __set_task_state(task, state);
 
                 /* didnt get the lock, go to sleep: */
                 spin_unlock_mutex(&lock->wait_lock, flags);
-                schedule();
+                __schedule();
                 spin_lock_mutex(&lock->wait_lock, flags);
         }
 
 done:
         lock_acquired(&lock->dep_map, ip);
         /* got the lock - rejoice! */
-        mutex_remove_waiter(lock, &waiter, task_thread_info(task));
-        debug_mutex_set_owner(lock, task_thread_info(task));
+        mutex_remove_waiter(lock, &waiter, current_thread_info());
+        mutex_set_owner(lock);
 
         /* set it to 0 if there are no waiters left: */
         if (likely(list_empty(&lock->wait_list)))
@@ -196,6 +265,7 @@ done:
         spin_unlock_mutex(&lock->wait_lock, flags);
 
         debug_mutex_free_waiter(&waiter);
+        preempt_enable();
 
         return 0;
 }
@@ -222,7 +292,8 @@ int __sched
 mutex_lock_interruptible_nested(struct mutex *lock, unsigned int subclass)
 {
         might_sleep();
-        return __mutex_lock_common(lock, TASK_INTERRUPTIBLE, subclass, _RET_IP_);
+        return __mutex_lock_common(lock, TASK_INTERRUPTIBLE,
+                                   subclass, _RET_IP_);
 }
 
 EXPORT_SYMBOL_GPL(mutex_lock_interruptible_nested);
@@ -260,8 +331,6 @@ __mutex_unlock_common_slowpath(atomic_t *lock_count, int nested)
                 wake_up_process(waiter->task);
         }
 
-        debug_mutex_clear_owner(lock);
-
         spin_unlock_mutex(&lock->wait_lock, flags);
 }
 
@@ -298,18 +367,30 @@ __mutex_lock_interruptible_slowpath(atomic_t *lock_count);
  */
 int __sched mutex_lock_interruptible(struct mutex *lock)
 {
+        int ret;
+
         might_sleep();
-        return __mutex_fastpath_lock_retval
+        ret =  __mutex_fastpath_lock_retval
                         (&lock->count, __mutex_lock_interruptible_slowpath);
+        if (!ret)
+                mutex_set_owner(lock);
+
+        return ret;
 }
 
 EXPORT_SYMBOL(mutex_lock_interruptible);
 
 int __sched mutex_lock_killable(struct mutex *lock)
 {
+        int ret;
+
         might_sleep();
-        return __mutex_fastpath_lock_retval
+        ret = __mutex_fastpath_lock_retval
                         (&lock->count, __mutex_lock_killable_slowpath);
+        if (!ret)
+                mutex_set_owner(lock);
+
+        return ret;
 }
 EXPORT_SYMBOL(mutex_lock_killable);
 
@@ -352,9 +433,10 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
 
         prev = atomic_xchg(&lock->count, -1);
         if (likely(prev == 1)) {
-                debug_mutex_set_owner(lock, current_thread_info());
+                mutex_set_owner(lock);
                 mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
         }
+
         /* Set it back to 0 if there are no waiters: */
         if (likely(list_empty(&lock->wait_list)))
                 atomic_set(&lock->count, 0);
@@ -380,8 +462,13 @@ static inline int __mutex_trylock_slowpath(atomic_t *lock_count)
  */
 int __sched mutex_trylock(struct mutex *lock)
 {
-        return __mutex_fastpath_trylock(&lock->count,
-                                        __mutex_trylock_slowpath);
+        int ret;
+
+        ret = __mutex_fastpath_trylock(&lock->count, __mutex_trylock_slowpath);
+        if (ret)
+                mutex_set_owner(lock);
+
+        return ret;
 }
 
 EXPORT_SYMBOL(mutex_trylock);
diff --git a/kernel/mutex.h b/kernel/mutex.h
index a075dafbb290..67578ca48f94 100644
--- a/kernel/mutex.h
+++ b/kernel/mutex.h
@@ -16,8 +16,26 @@
 #define mutex_remove_waiter(lock, waiter, ti) \
                 __list_del((waiter)->list.prev, (waiter)->list.next)
 
-#define debug_mutex_set_owner(lock, new_owner)          do { } while (0)
-#define debug_mutex_clear_owner(lock)                   do { } while (0)
+#ifdef CONFIG_SMP
+static inline void mutex_set_owner(struct mutex *lock)
+{
+        lock->owner = current_thread_info();
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+        lock->owner = NULL;
+}
+#else
+static inline void mutex_set_owner(struct mutex *lock)
+{
+}
+
+static inline void mutex_clear_owner(struct mutex *lock)
+{
+}
+#endif
+
 #define debug_mutex_wake_waiter(lock, waiter)           do { } while (0)
 #define debug_mutex_free_waiter(waiter)                 do { } while (0)
 #define debug_mutex_add_waiter(lock, waiter, ti)        do { } while (0)
diff --git a/kernel/sched.c b/kernel/sched.c
index 5757e03cfac0..196d48babbef 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4942,15 +4942,13 @@ pick_next_task(struct rq *rq)
 /*
  * schedule() is the main scheduler function.
  */
-asmlinkage void __sched schedule(void)
+asmlinkage void __sched __schedule(void)
 {
         struct task_struct *prev, *next;
         unsigned long *switch_count;
         struct rq *rq;
         int cpu;
 
-need_resched:
-        preempt_disable();
         cpu = smp_processor_id();
         rq = cpu_rq(cpu);
         rcu_qsctr_inc(cpu);
@@ -5007,13 +5005,80 @@ need_resched_nonpreemptible:
 
         if (unlikely(reacquire_kernel_lock(current) < 0))
                 goto need_resched_nonpreemptible;
+}
 
+asmlinkage void __sched schedule(void)
+{
+need_resched:
+        preempt_disable();
+        __schedule();
         preempt_enable_no_resched();
         if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
                 goto need_resched;
 }
 EXPORT_SYMBOL(schedule);
 
+#ifdef CONFIG_SMP
+/*
+ * Look out! "owner" is an entirely speculative pointer
+ * access and not reliable.
+ */
+int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
+{
+        unsigned int cpu;
+        struct rq *rq;
+
+        if (!sched_feat(OWNER_SPIN))
+                return 0;
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+        /*
+         * Need to access the cpu field knowing that
+         * DEBUG_PAGEALLOC could have unmapped it if
+         * the mutex owner just released it and exited.
+         */
+        if (probe_kernel_address(&owner->cpu, cpu))
+                goto out;
+#else
+        cpu = owner->cpu;
+#endif
+
+        /*
+         * Even if the access succeeded (likely case),
+         * the cpu field may no longer be valid.
+         */
+        if (cpu >= nr_cpumask_bits)
+                goto out;
+
+        /*
+         * We need to validate that we can do a
+         * get_cpu() and that we have the percpu area.
+         */
+        if (!cpu_online(cpu))
+                goto out;
+
+        rq = cpu_rq(cpu);
+
+        for (;;) {
+                /*
+                 * Owner changed, break to re-assess state.
+                 */
+                if (lock->owner != owner)
+                        break;
+
+                /*
+                 * Is that owner really running on that cpu?
+                 */
+                if (task_thread_info(rq->curr) != owner || need_resched())
+                        return 0;
+
+                cpu_relax();
+        }
+out:
+        return 1;
+}
+#endif
+
 #ifdef CONFIG_PREEMPT
 /*
  * this is the entry point to schedule() from in-kernel preemption
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index 76f61756e677..4569bfa7df9b 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -14,3 +14,4 @@ SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
 SCHED_FEAT(ASYM_EFF_LOAD, 1)
 SCHED_FEAT(WAKEUP_OVERLAP, 0)
 SCHED_FEAT(LAST_BUDDY, 1)
+SCHED_FEAT(OWNER_SPIN, 1)
diff --git a/kernel/timer.c b/kernel/timer.c
index 9b77fc9a9ac8..b4555568b4e4 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -491,14 +491,18 @@ static inline void debug_timer_free(struct timer_list *timer)
         debug_object_free(timer, &timer_debug_descr);
 }
 
-static void __init_timer(struct timer_list *timer);
+static void __init_timer(struct timer_list *timer,
+                         const char *name,
+                         struct lock_class_key *key);
 
-void init_timer_on_stack(struct timer_list *timer)
+void init_timer_on_stack_key(struct timer_list *timer,
+                             const char *name,
+                             struct lock_class_key *key)
 {
         debug_object_init_on_stack(timer, &timer_debug_descr);
-        __init_timer(timer);
+        __init_timer(timer, name, key);
 }
-EXPORT_SYMBOL_GPL(init_timer_on_stack);
+EXPORT_SYMBOL_GPL(init_timer_on_stack_key);
 
 void destroy_timer_on_stack(struct timer_list *timer)
 {
@@ -512,7 +516,9 @@ static inline void debug_timer_activate(struct timer_list *timer) { }
 static inline void debug_timer_deactivate(struct timer_list *timer) { }
 #endif
 
-static void __init_timer(struct timer_list *timer)
+static void __init_timer(struct timer_list *timer,
+                         const char *name,
+                         struct lock_class_key *key)
 {
         timer->entry.next = NULL;
         timer->base = __raw_get_cpu_var(tvec_bases);
@@ -521,6 +527,7 @@ static void __init_timer(struct timer_list *timer)
         timer->start_pid = -1;
         memset(timer->start_comm, 0, TASK_COMM_LEN);
 #endif
+        lockdep_init_map(&timer->lockdep_map, name, key, 0);
 }
 
 /**
@@ -530,19 +537,23 @@ static void __init_timer(struct timer_list *timer)
  * init_timer() must be done to a timer prior calling *any* of the
  * other timer functions.
  */
-void init_timer(struct timer_list *timer)
+void init_timer_key(struct timer_list *timer,
+                    const char *name,
+                    struct lock_class_key *key)
 {
         debug_timer_init(timer);
-        __init_timer(timer);
+        __init_timer(timer, name, key);
 }
-EXPORT_SYMBOL(init_timer);
+EXPORT_SYMBOL(init_timer_key);
 
-void init_timer_deferrable(struct timer_list *timer)
+void init_timer_deferrable_key(struct timer_list *timer,
+                               const char *name,
+                               struct lock_class_key *key)
 {
-        init_timer(timer);
+        init_timer_key(timer, name, key);
         timer_set_deferrable(timer);
 }
-EXPORT_SYMBOL(init_timer_deferrable);
+EXPORT_SYMBOL(init_timer_deferrable_key);
 
 static inline void detach_timer(struct timer_list *timer,
                                 int clear_pending)
@@ -826,6 +837,15 @@ EXPORT_SYMBOL(try_to_del_timer_sync);
  */
 int del_timer_sync(struct timer_list *timer)
 {
+#ifdef CONFIG_LOCKDEP
+        unsigned long flags;
+
+        local_irq_save(flags);
+        lock_map_acquire(&timer->lockdep_map);
+        lock_map_release(&timer->lockdep_map);
+        local_irq_restore(flags);
+#endif
+
         for (;;) {
                 int ret = try_to_del_timer_sync(timer);
                 if (ret >= 0)
@@ -897,10 +917,36 @@ static inline void __run_timers(struct tvec_base *base)
 
                         set_running_timer(base, timer);
                         detach_timer(timer, 1);
+
                         spin_unlock_irq(&base->lock);
                         {
                                 int preempt_count = preempt_count();
+
+#ifdef CONFIG_LOCKDEP
+                                /*
+                                 * It is permissible to free the timer from
+                                 * inside the function that is called from
+                                 * it, this we need to take into account for
+                                 * lockdep too. To avoid bogus "held lock
+                                 * freed" warnings as well as problems when
+                                 * looking into timer->lockdep_map, make a
+                                 * copy and use that here.
+                                 */
+                                struct lockdep_map lockdep_map =
+                                        timer->lockdep_map;
+#endif
+                                /*
+                                 * Couple the lock chain with the lock chain at
+                                 * del_timer_sync() by acquiring the lock_map
+                                 * around the fn() call here and in
+                                 * del_timer_sync().
+                                 */
+                                lock_map_acquire(&lockdep_map);
+
                                 fn(data);
+
+                                lock_map_release(&lockdep_map);
+
                                 if (preempt_count != preempt_count()) {
                                         printk(KERN_ERR "huh, entered %p "
                                                "with preempt_count %08x, exited"