| Date | Sun, 05 Feb 2012 23:10:44 +0100 | From | Willy Tarreau <> | Subject | [PATCH 55/91] Make scsi_free_queue() kill pending SCSI commands |
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2.6.27-longterm review patch. If anyone has any objections, please let us know.
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commit 3308511c93e6ad0d3c58984ecd6e5e57f96b12c8 upstream.
Make sure that SCSI device removal via scsi_remove_host() does finish all pending SCSI commands. Currently that's not the case and hence removal of a SCSI host during I/O can cause a deadlock. See also "blkdev_issue_discard() hangs forever if underlying storage device is removed" (http://bugzilla.kernel.org/show_bug.cgi?id=40472). See also http://lkml.org/lkml/2011/8/27/6.
Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- drivers/scsi/hosts.c | 9 ++++++--- drivers/scsi/scsi_lib.c | 9 +++++++++ 2 files changed, 15 insertions(+), 3 deletions(-)
Index: longterm-2.6.27/drivers/scsi/hosts.c =================================================================== --- longterm-2.6.27.orig/drivers/scsi/hosts.c 2012-02-05 22:34:33.360914737 +0100 +++ longterm-2.6.27/drivers/scsi/hosts.c 2012-02-05 22:34:42.692915134 +0100 @@ -269,14 +269,17 @@ { struct Scsi_Host *shost = dev_to_shost(dev); struct device *parent = dev->parent; + struct request_queue *q; if (shost->ehandler) kthread_stop(shost->ehandler); if (shost->work_q) destroy_workqueue(shost->work_q); - if (shost->uspace_req_q) { - kfree(shost->uspace_req_q->queuedata); - scsi_free_queue(shost->uspace_req_q); + q = shost->uspace_req_q; + if (q) { + kfree(q->queuedata); + q->queuedata = NULL; + scsi_free_queue(q); } scsi_destroy_command_freelist(shost); Index: longterm-2.6.27/drivers/scsi/scsi_lib.c =================================================================== --- longterm-2.6.27.orig/drivers/scsi/scsi_lib.c 2012-02-05 22:34:33.364914767 +0100 +++ longterm-2.6.27/drivers/scsi/scsi_lib.c 2012-02-05 22:34:42.697916475 +0100 @@ -1680,6 +1680,15 @@ void scsi_free_queue(struct request_queue *q) { + unsigned long flags; + + WARN_ON(q->queuedata); + + /* cause scsi_request_fn() to kill all non-finished requests */ + spin_lock_irqsave(q->queue_lock, flags); + q->request_fn(q); + spin_unlock_irqrestore(q->queue_lock, flags); + blk_cleanup_queue(q); }
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