From c4ec1c369322fc6dd1512975e11d2d2abe90a705 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Thu, 31 Jul 2008 13:31:33 +0200 Subject: [PATCH] SCSI: bsg: fix bsg_mutex hang with device removal commit 3f27e3ed11e67c5ee19d560a50eafd93cf8c6682 upstream [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 Signed-off-by: FUJITA Tomonori Signed-off-by: James Bottomley CC: Oliver Pinter Signed-off-by: Greg Kroah-Hartman --- block/bsg.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/block/bsg.c b/block/bsg.c index 54d617f7df3e..052647150fa2 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -725,8 +725,13 @@ 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); @@ -742,10 +747,8 @@ 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); -- 2.39.5