[PATCH] device-mapper dm-mpath: endio spinlock fix

do_end_io() can be called without interrupts blocked.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index f9b7b32d5d5c..f72a82fb9434 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -1000,6 +1000,7 @@ static int do_end_io(struct multipath *m, struct bio *bio,
 {
         struct hw_handler *hwh = &m->hw_handler;
         unsigned err_flags = MP_FAIL_PATH;      /* Default behavior */
+        unsigned long flags;
 
         if (!error)
                 return 0;       /* I/O complete */
@@ -1010,17 +1011,17 @@ static int do_end_io(struct multipath *m, struct bio *bio,
         if (error == -EOPNOTSUPP)
                 return error;
 
-        spin_lock(&m->lock);
+        spin_lock_irqsave(&m->lock, flags);
         if (!m->nr_valid_paths) {
                 if (!m->queue_if_no_path) {
-                        spin_unlock(&m->lock);
+                        spin_unlock_irqrestore(&m->lock, flags);
                         return -EIO;
                 } else {
-                        spin_unlock(&m->lock);
+                        spin_unlock_irqrestore(&m->lock, flags);
                         goto requeue;
                 }
         }
-        spin_unlock(&m->lock);
+        spin_unlock_irqrestore(&m->lock, flags);
 
         if (hwh->type && hwh->type->error)
                 err_flags = hwh->type->error(hwh, bio);
@@ -1040,12 +1041,12 @@ static int do_end_io(struct multipath *m, struct bio *bio,
         dm_bio_restore(&mpio->details, bio);
 
         /* queue for the daemon to resubmit or fail */
-        spin_lock(&m->lock);
+        spin_lock_irqsave(&m->lock, flags);
         bio_list_add(&m->queued_ios, bio);
         m->queue_size++;
         if (!m->queue_io)
                 queue_work(kmultipathd, &m->process_queued_ios);
-        spin_unlock(&m->lock);
+        spin_unlock_irqrestore(&m->lock, flags);
 
         return 1;       /* io not complete */
 }