dm: tidy dm_suspend

Tidy dm_suspend function

 - change return value logic in dm_suspend
 - use atomic_read only once.
 - move DMF_BLOCK_IO clearing into one place

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c1ad7d77dbcd..5191954a18b2 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1270,6 +1270,8 @@ static void __flush_deferred_io(struct mapped_device *md)
                 if (__split_bio(md, c))
                         bio_io_error(c);
         }
+
+        clear_bit(DMF_BLOCK_IO, &md->flags);
 }
 
 static void __merge_pushback_list(struct mapped_device *md)
@@ -1355,14 +1357,16 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 {
         struct dm_table *map = NULL;
         DECLARE_WAITQUEUE(wait, current);
-        int r = -EINVAL;
+        int pending, r = 0;
         int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
         int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
 
         mutex_lock(&md->suspend_lock);
 
-        if (dm_suspended(md))
+        if (dm_suspended(md)) {
+                r = -EINVAL;
                 goto out_unlock;
+        }
 
         map = dm_get_table(md);
 
@@ -1417,7 +1421,8 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
                 set_current_state(TASK_INTERRUPTIBLE);
 
                 smp_mb();
-                if (!atomic_read(&md->pending) || signal_pending(current))
+                pending = atomic_read(&md->pending);
+                if (!pending || signal_pending(current))
                         break;
 
                 io_schedule();
@@ -1431,12 +1436,12 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
                 __merge_pushback_list(md);
 
         /* were we interrupted ? */
-        r = -EINTR;
-        if (atomic_read(&md->pending)) {
-                clear_bit(DMF_BLOCK_IO, &md->flags);
+        if (pending) {
                 __flush_deferred_io(md);
                 up_write(&md->io_lock);
+
                 unlock_fs(md);
+                r = -EINTR;
                 goto out; /* pushback list is already flushed, so skip flush */
         }
         up_write(&md->io_lock);
@@ -1445,8 +1450,6 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
 
         set_bit(DMF_SUSPENDED, &md->flags);
 
-        r = 0;
-
 flush_and_out:
         if (r && noflush) {
                 /*
@@ -1490,8 +1493,6 @@ int dm_resume(struct mapped_device *md)
                 goto out;
 
         down_write(&md->io_lock);
-        clear_bit(DMF_BLOCK_IO, &md->flags);
-
         __flush_deferred_io(md);
         up_write(&md->io_lock);