Merge branch 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:
 "This is quite late but these need to be backported anyway.

  This is the fix for a long-standing cpuset bug which existed from
  2009.  cpuset makes use of PF_SPREAD_{PAGE|SLAB} flags to modify the
  task's memory allocation behavior according to the settings of the
  cpuset it belongs to; unfortunately, when those flags have to be
  changed, cpuset did so directly even whlie the target task is running,
  which is obviously racy as task->flags may be modified by the task
  itself at any time.  This obscure bug manifested as corrupt
  PF_USED_MATH flag leading to a weird crash.

  The bug is fixed by moving the flag to task->atomic_flags.  The first
  two are prepatory ones to help defining atomic_flags accessors and the
  third one is the actual fix"

* 'for-3.17-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags
  sched: add macros to define bitops for task atomic flags
  sched: fix confusing PFA_NO_NEW_PRIVS constant

6 files changed, 43 insertions, 24 deletions

diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt
index 7740038d82bc..3c94ff3f9693 100644
--- a/Documentation/cgroups/cpusets.txt
+++ b/Documentation/cgroups/cpusets.txt
@@ -345,14 +345,14 @@ the named feature on.
 The implementation is simple.
 
 Setting the flag 'cpuset.memory_spread_page' turns on a per-process flag
-PF_SPREAD_PAGE for each task that is in that cpuset or subsequently
+PFA_SPREAD_PAGE for each task that is in that cpuset or subsequently
 joins that cpuset.  The page allocation calls for the page cache
-is modified to perform an inline check for this PF_SPREAD_PAGE task
+is modified to perform an inline check for this PFA_SPREAD_PAGE task
 flag, and if set, a call to a new routine cpuset_mem_spread_node()
 returns the node to prefer for the allocation.
 
 Similarly, setting 'cpuset.memory_spread_slab' turns on the flag
-PF_SPREAD_SLAB, and appropriately marked slab caches will allocate
+PFA_SPREAD_SLAB, and appropriately marked slab caches will allocate
 pages from the node returned by cpuset_mem_spread_node().
 
 The cpuset_mem_spread_node() routine is also simple.  It uses the
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index ade2390ffe92..6e39c9bb0dae 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -93,12 +93,12 @@ extern int cpuset_slab_spread_node(void);
 
 static inline int cpuset_do_page_mem_spread(void)
 {
-        return current->flags & PF_SPREAD_PAGE;
+        return task_spread_page(current);
 }
 
 static inline int cpuset_do_slab_mem_spread(void)
 {
-        return current->flags & PF_SPREAD_SLAB;
+        return task_spread_slab(current);
 }
 
 extern int current_cpuset_is_being_rebound(void);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1f07040d28e3..b867a4dab38a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1903,8 +1903,6 @@ extern void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut,
 #define PF_KTHREAD      0x00200000      /* I am a kernel thread */
 #define PF_RANDOMIZE    0x00400000      /* randomize virtual address space */
 #define PF_SWAPWRITE    0x00800000      /* Allowed to write to swap */
-#define PF_SPREAD_PAGE  0x01000000      /* Spread page cache over cpuset */
-#define PF_SPREAD_SLAB  0x02000000      /* Spread some slab caches over cpuset */
 #define PF_NO_SETAFFINITY 0x04000000    /* Userland is not allowed to meddle with cpus_allowed */
 #define PF_MCE_EARLY    0x08000000      /* Early kill for mce process policy */
 #define PF_MUTEX_TESTER 0x20000000      /* Thread belongs to the rt mutex tester */
@@ -1957,17 +1955,31 @@ static inline void memalloc_noio_restore(unsigned int flags)
 }
 
 /* Per-process atomic flags. */
-#define PFA_NO_NEW_PRIVS 0x00000001     /* May not gain new privileges. */
-
-static inline bool task_no_new_privs(struct task_struct *p)
-{
-        return test_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags);
-}
-
-static inline void task_set_no_new_privs(struct task_struct *p)
-{
-        set_bit(PFA_NO_NEW_PRIVS, &p->atomic_flags);
-}
+#define PFA_NO_NEW_PRIVS 0      /* May not gain new privileges. */
+#define PFA_SPREAD_PAGE  1      /* Spread page cache over cpuset */
+#define PFA_SPREAD_SLAB  2      /* Spread some slab caches over cpuset */
+
+
+#define TASK_PFA_TEST(name, func)                                       \
+        static inline bool task_##func(struct task_struct *p)           \
+        { return test_bit(PFA_##name, &p->atomic_flags); }
+#define TASK_PFA_SET(name, func)                                        \
+        static inline void task_set_##func(struct task_struct *p)       \
+        { set_bit(PFA_##name, &p->atomic_flags); }
+#define TASK_PFA_CLEAR(name, func)                                      \
+        static inline void task_clear_##func(struct task_struct *p)     \
+        { clear_bit(PFA_##name, &p->atomic_flags); }
+
+TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs)
+TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs)
+
+TASK_PFA_TEST(SPREAD_PAGE, spread_page)
+TASK_PFA_SET(SPREAD_PAGE, spread_page)
+TASK_PFA_CLEAR(SPREAD_PAGE, spread_page)
+
+TASK_PFA_TEST(SPREAD_SLAB, spread_slab)
+TASK_PFA_SET(SPREAD_SLAB, spread_slab)
+TASK_PFA_CLEAR(SPREAD_SLAB, spread_slab)
 
 /*
  * task->jobctl flags
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 22874d7cf2c0..52cb04c993b7 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -365,13 +365,14 @@ static void cpuset_update_task_spread_flag(struct cpuset *cs,
                                         struct task_struct *tsk)
 {
         if (is_spread_page(cs))
-                tsk->flags |= PF_SPREAD_PAGE;
+                task_set_spread_page(tsk);
         else
-                tsk->flags &= ~PF_SPREAD_PAGE;
+                task_clear_spread_page(tsk);
+
         if (is_spread_slab(cs))
-                tsk->flags |= PF_SPREAD_SLAB;
+                task_set_spread_slab(tsk);
         else
-                tsk->flags &= ~PF_SPREAD_SLAB;
+                task_clear_spread_slab(tsk);
 }
 
 /*
diff --git a/mm/slab.c b/mm/slab.c
index b8b619bc84ad..7c52b3890d25 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2987,7 +2987,7 @@ out:
 
 #ifdef CONFIG_NUMA
 /*
- * Try allocating on another node if PF_SPREAD_SLAB is a mempolicy is set.
+ * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set.
  *
  * If we are in_interrupt, then process context, including cpusets and
  * mempolicy, may not apply and should not be used for allocation policy.
@@ -3219,7 +3219,7 @@ __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
 {
         void *objp;
 
-        if (current->mempolicy || unlikely(current->flags & PF_SPREAD_SLAB)) {
+        if (current->mempolicy || cpuset_do_slab_mem_spread()) {
                 objp = alternate_node_alloc(cache, flags);
                 if (objp)
                         goto out;
diff --git a/scripts/tags.sh b/scripts/tags.sh
index cbfd269a6011..293828bfd4ac 100755
--- a/scripts/tags.sh
+++ b/scripts/tags.sh
@@ -197,6 +197,9 @@ exuberant()
         --regex-c++='/SETPCGFLAG\(([^,)]*).*/SetPageCgroup\1/'          \
         --regex-c++='/CLEARPCGFLAG\(([^,)]*).*/ClearPageCgroup\1/'      \
         --regex-c++='/TESTCLEARPCGFLAG\(([^,)]*).*/TestClearPageCgroup\1/' \
+        --regex-c++='/TASK_PFA_TEST\([^,]*,\s*([^)]*)\)/task_\1/'       \
+        --regex-c++='/TASK_PFA_SET\([^,]*,\s*([^)]*)\)/task_set_\1/'    \
+        --regex-c++='/TASK_PFA_CLEAR\([^,]*,\s*([^)]*)\)/task_clear_\1/'\
         --regex-c='/PCI_OP_READ\((\w*).*[1-4]\)/pci_bus_read_config_\1/' \
         --regex-c='/PCI_OP_WRITE\((\w*).*[1-4]\)/pci_bus_write_config_\1/' \
         --regex-c='/DEFINE_(MUTEX|SEMAPHORE|SPINLOCK)\((\w*)/\2/v/'     \
@@ -260,6 +263,9 @@ emacs()
         --regex='/SETPCGFLAG\(([^,)]*).*/SetPageCgroup\1/'      \
         --regex='/CLEARPCGFLAG\(([^,)]*).*/ClearPageCgroup\1/'  \
         --regex='/TESTCLEARPCGFLAG\(([^,)]*).*/TestClearPageCgroup\1/' \
+        --regex='/TASK_PFA_TEST\([^,]*,\s*([^)]*)\)/task_\1/'           \
+        --regex='/TASK_PFA_SET\([^,]*,\s*([^)]*)\)/task_set_\1/'        \
+        --regex='/TASK_PFA_CLEAR\([^,]*,\s*([^)]*)\)/task_clear_\1/'    \
         --regex='/_PE(\([^,)]*\).*/PEVENT_ERRNO__\1/'           \
         --regex='/PCI_OP_READ(\([a-z]*[a-z]\).*[1-4])/pci_bus_read_config_\1/' \
         --regex='/PCI_OP_WRITE(\([a-z]*[a-z]\).*[1-4])/pci_bus_write_config_\1/'\