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>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index c1ad7d7..5191954 100644 (file)
--- 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);