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authorFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>2008-05-29 07:56:55 +0900
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-07-12 08:22:23 -0500
commit3f27e3ed11e67c5ee19d560a50eafd93cf8c6682 (patch)
treed2ed33ce7ca12c8b7e1c585ba9b2097095b0f89c
parent30e9ba9f2001f45960507f1963551311a67d0209 (diff)
[SCSI] bsg: fix bsg_mutex hang with device removal
We don't need to hold bsg_mutex during bsg_complete_all_commands(). It leads to a problem that we block bsg_unregister_queue during bsg_complete_all_commands (untill all the outstanding commands complete). Thanks to Pete Wyckoff for finding the bug and testing the patch. The detailed bug report is: http://marc.info/?l=linux-scsi&m=121182137132145&w=2 Tested-by: Pete Wyckoff <pw@osc.edu> Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
-rw-r--r--block/bsg.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/block/bsg.c b/block/bsg.c
index f0b7cd343216..7cdec32205d8 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -724,8 +724,13 @@ static int bsg_put_device(struct bsg_device *bd)
mutex_lock(&bsg_mutex);
do_free = atomic_dec_and_test(&bd->ref_count);
- if (!do_free)
+ if (!do_free) {
+ mutex_unlock(&bsg_mutex);
goto out;
+ }
+
+ hlist_del(&bd->dev_list);
+ mutex_unlock(&bsg_mutex);
dprintk("%s: tearing down\n", bd->name);
@@ -741,10 +746,8 @@ static int bsg_put_device(struct bsg_device *bd)
*/
ret = bsg_complete_all_commands(bd);
- hlist_del(&bd->dev_list);
kfree(bd);
out:
- mutex_unlock(&bsg_mutex);
kref_put(&q->bsg_dev.ref, bsg_kref_release_function);
if (do_free)
blk_put_queue(q);