mm: Replace PF_MEMALLOC_NOFS with memalloc_nofs

We're short on PF_* flags, so make memalloc_nofs its own bit where we
have plenty of space.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index bcfc288dba3fb80b9000e716f570da5c2a83965a..87d66c13bf5c33b3a700ff89ee66bb677dba5142 100644 (file)
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1502,7 +1502,7 @@ iomap_do_writepage(struct page *page, struct writeback_control *wbc, void *data)
         * Given that we do not allow direct reclaim to call us, we should
         * never be called in a recursive filesystem reclaim context.
         */
-       if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS))
+       if (WARN_ON_ONCE(current->memalloc_nofs))
                goto redirty;
 
        /*

diff --git a/include/linux/sched.h b/include/linux/sched.h
index cf18a3d2bc4c6207eb0027d2bc79a18d711507ef..eaf36ae1fde2eb9679e86d0c37f5b1bd637e99c8 100644 (file)
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -802,6 +802,7 @@ struct task_struct {
        unsigned                        in_memstall:1;
 #endif
        unsigned                        memalloc_noio:1;
+       unsigned                        memalloc_nofs:1;
 
        unsigned long                   atomic_flags; /* Flags requiring atomic access. */
 
@@ -1505,7 +1506,6 @@ extern struct pid *cad_pid;
 #define PF_NOFREEZE            0x00008000      /* This thread should not be frozen */
 #define PF_FROZEN              0x00010000      /* Frozen for system suspend */
 #define PF_KSWAPD              0x00020000      /* I am kswapd */
-#define PF_MEMALLOC_NOFS       0x00040000      /* All allocation requests will inherit GFP_NOFS */
 #define PF_LOCAL_THROTTLE      0x00100000      /* Throttle writes only against the bdi I write to,
                                                 * I am cleaning dirty pages from some other bdi. */
 #define PF_KTHREAD             0x00200000      /* I am a kernel thread */

diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
index b0089eadc3670be6037fde0ef49512b467f827bd..08bc9d0606a877526c30a8e76f4e28683f0ea324 100644 (file)
--- a/include/linux/sched/mm.h
+++ b/include/linux/sched/mm.h
@@ -175,20 +175,19 @@ static inline bool in_vfork(struct task_struct *tsk)
 
 /*
  * Applies per-task gfp context to the given allocation flags.
- * PF_MEMALLOC_NOFS implies GFP_NOFS
  * PF_MEMALLOC_NOCMA implies no allocation from CMA region.
  */
 static inline gfp_t current_gfp_context(gfp_t flags)
 {
-       if (unlikely(current->flags & (PF_MEMALLOC_NOFS | PF_MEMALLOC_NOCMA) ||
-                    current->memalloc_noio)) {
+       if (unlikely((current->flags & PF_MEMALLOC_NOCMA) ||
+                    current->memalloc_noio || current->memalloc_nofs)) {
                /*
                 * NOIO implies both NOIO and NOFS and it is a weaker context
                 * so always make sure it makes precedence
                 */
                if (current->memalloc_noio)
                        flags &= ~(__GFP_IO | __GFP_FS);
-               else if (current->flags & PF_MEMALLOC_NOFS)
+               else if (current->memalloc_nofs)
                        flags &= ~__GFP_FS;
 #ifdef CONFIG_CMA
                if (current->flags & PF_MEMALLOC_NOCMA)
@@ -254,8 +253,8 @@ static inline void memalloc_noio_restore(unsigned int flags)
  */
 static inline unsigned int memalloc_nofs_save(void)
 {
-       unsigned int flags = current->flags & PF_MEMALLOC_NOFS;
-       current->flags |= PF_MEMALLOC_NOFS;
+       unsigned int flags = current->memalloc_nofs;
+       current->memalloc_nofs = 1;
        return flags;
 }
 
@@ -269,7 +268,7 @@ static inline unsigned int memalloc_nofs_save(void)
  */
 static inline void memalloc_nofs_restore(unsigned int flags)
 {
-       current->flags = (current->flags & ~PF_MEMALLOC_NOFS) | flags;
+       current->memalloc_nofs = flags ? 1 : 0;
 }
 
 static inline unsigned int memalloc_noreclaim_save(void)