xfs: abstract PF_FSTRANS to PF_MEMALLOC_NOFS

xfs has defined PF_FSTRANS to declare a scope GFP_NOFS semantic quite
some time ago.  We would like to make this concept more generic and use
it for other filesystems as well.  Let's start by giving the flag a more
generic name PF_MEMALLOC_NOFS which is in line with an exiting
PF_MEMALLOC_NOIO already used for the same purpose for GFP_NOIO
contexts.  Replace all PF_FSTRANS usage from the xfs code in the first
step before we introduce a full API for it as xfs uses the flag directly
anyway.

This patch doesn't introduce any functional change.

Link: http://lkml.kernel.org/r/20170306131408.9828-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterba@suse.cz>
Cc: Jan Kara <jack@suse.cz>
Cc: Nikolay Borisov <nborisov@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 15 insertions, 13 deletions

diff --git a/fs/xfs/kmem.c b/fs/xfs/kmem.c
index 70a5b55e0870..d0ac1a065539 100644
--- a/fs/xfs/kmem.c
+++ b/fs/xfs/kmem.c
@@ -63,13 +63,13 @@ kmem_zalloc_large(size_t size, xfs_km_flags_t flags)
          * context via PF_MEMALLOC_NOIO to prevent memory reclaim re-entering
          * the filesystem here and potentially deadlocking.
          */
-        if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
+        if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS))
                 noio_flag = memalloc_noio_save();
 
         lflags = kmem_flags_convert(flags);
         ptr = __vmalloc(size, lflags | __GFP_HIGHMEM | __GFP_ZERO, PAGE_KERNEL);
 
-        if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
+        if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS))
                 memalloc_noio_restore(noio_flag);
 
         return ptr;
diff --git a/fs/xfs/kmem.h b/fs/xfs/kmem.h
index f0fc84fcaac2..a6c8da40c70d 100644
--- a/fs/xfs/kmem.h
+++ b/fs/xfs/kmem.h
@@ -50,7 +50,7 @@ kmem_flags_convert(xfs_km_flags_t flags)
                 lflags = GFP_ATOMIC | __GFP_NOWARN;
         } else {
                 lflags = GFP_KERNEL | __GFP_NOWARN;
-                if ((current->flags & PF_FSTRANS) || (flags & KM_NOFS))
+                if ((current->flags & PF_MEMALLOC_NOFS) || (flags & KM_NOFS))
                         lflags &= ~__GFP_FS;
         }
 
diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index c3decedc9455..3059a3ec7ecb 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -2886,7 +2886,7 @@ xfs_btree_split_worker(
         struct xfs_btree_split_args     *args = container_of(work,
                                                 struct xfs_btree_split_args, work);
         unsigned long           pflags;
-        unsigned long           new_pflags = PF_FSTRANS;
+        unsigned long           new_pflags = PF_MEMALLOC_NOFS;
 
         /*
          * we are in a transaction context here, but may also be doing work
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 61494295d92f..05eca126c688 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -189,7 +189,7 @@ xfs_setfilesize_trans_alloc(
          * We hand off the transaction to the completion thread now, so
          * clear the flag here.
          */
-        current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+        current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
         return 0;
 }
 
@@ -252,7 +252,7 @@ xfs_setfilesize_ioend(
          * thus we need to mark ourselves as being in a transaction manually.
          * Similarly for freeze protection.
          */
-        current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
+        current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
         __sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS);
 
         /* we abort the update if there was an IO error */
@@ -1016,7 +1016,7 @@ xfs_do_writepage(
          * Given that we do not allow direct reclaim to call us, we should
          * never be called while in a filesystem transaction.
          */
-        if (WARN_ON_ONCE(current->flags & PF_FSTRANS))
+        if (WARN_ON_ONCE(current->flags & PF_MEMALLOC_NOFS))
                 goto redirty;
 
         /*
diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 70f42ea86dfb..f5969c8274fc 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -134,7 +134,7 @@ xfs_trans_reserve(
         bool            rsvd = (tp->t_flags & XFS_TRANS_RESERVE) != 0;
 
         /* Mark this thread as being in a transaction */
-        current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
+        current_set_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
 
         /*
          * Attempt to reserve the needed disk blocks by decrementing
@@ -144,7 +144,7 @@ xfs_trans_reserve(
         if (blocks > 0) {
                 error = xfs_mod_fdblocks(tp->t_mountp, -((int64_t)blocks), rsvd);
                 if (error != 0) {
-                        current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+                        current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
                         return -ENOSPC;
                 }
                 tp->t_blk_res += blocks;
@@ -221,7 +221,7 @@ undo_blocks:
                 tp->t_blk_res = 0;
         }
 
-        current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+        current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
 
         return error;
 }
@@ -914,7 +914,7 @@ __xfs_trans_commit(
 
         xfs_log_commit_cil(mp, tp, &commit_lsn, regrant);
 
-        current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+        current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
         xfs_trans_free(tp);
 
         /*
@@ -944,7 +944,7 @@ out_unreserve:
                 if (commit_lsn == -1 && !error)
                         error = -EIO;
         }
-        current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+        current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
         xfs_trans_free_items(tp, NULLCOMMITLSN, !!error);
         xfs_trans_free(tp);
 
@@ -998,7 +998,7 @@ xfs_trans_cancel(
                 xfs_log_done(mp, tp->t_ticket, NULL, false);
 
         /* mark this thread as no longer being in a transaction */
-        current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
+        current_restore_flags_nested(&tp->t_pflags, PF_MEMALLOC_NOFS);
 
         xfs_trans_free_items(tp, NULLCOMMITLSN, dirty);
         xfs_trans_free(tp);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 3d4fa448223f..8ac11465ac5b 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1237,6 +1237,8 @@ extern struct pid *cad_pid;
 #define PF_FREEZER_SKIP         0x40000000      /* Freezer should not count it as freezable */
 #define PF_SUSPEND_TASK         0x80000000      /* This thread called freeze_processes() and should not be frozen */
 
+#define PF_MEMALLOC_NOFS PF_FSTRANS     /* Transition to a more generic GFP_NOFS scope semantic */
+
 /*
  * Only the _current_ task can read/write to tsk->flags, but other
  * tasks can access tsk->flags in readonly mode for example