Patch "block: Relax a check in blk_start_queue()" has been added to the 4.4-stable tree

Patch "block: Relax a check in blk_start_queue()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    block: Relax a check in blk_start_queue()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     block-relax-a-check-in-blk_start_queue.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 4ddd56b003f251091a67c15ae3fe4a5c5c5e390a Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche@wdc.com>
Date: Thu, 17 Aug 2017 13:12:44 -0700
Subject: block: Relax a check in blk_start_queue()

From: Bart Van Assche <bart.vanassche@wdc.com>

commit 4ddd56b003f251091a67c15ae3fe4a5c5c5e390a upstream.

Calling blk_start_queue() from interrupt context with the queue
lock held and without disabling IRQs, as the skd driver does, is
safe. This patch avoids that loading the skd driver triggers the
following warning:

WARNING: CPU: 11 PID: 1348 at block/blk-core.c:283 blk_start_queue+0x84/0xa0
RIP: 0010:blk_start_queue+0x84/0xa0
Call Trace:
 skd_unquiesce_dev+0x12a/0x1d0 [skd]
 skd_complete_internal+0x1e7/0x5a0 [skd]
 skd_complete_other+0xc2/0xd0 [skd]
 skd_isr_completion_posted.isra.30+0x2a5/0x470 [skd]
 skd_isr+0x14f/0x180 [skd]
 irq_forced_thread_fn+0x2a/0x70
 irq_thread+0x144/0x1a0
 kthread+0x125/0x140
 ret_from_fork+0x2a/0x40

Fixes: commit a038e2536472 ("[PATCH] blk_start_queue() must be called with irq disabled - add warning")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 block/blk-core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -233,7 +233,7 @@ EXPORT_SYMBOL(blk_start_queue_async);
  **/
 void blk_start_queue(struct request_queue *q)
 {
-	WARN_ON(!irqs_disabled());
+	WARN_ON(!in_interrupt() && !irqs_disabled());
 
 	queue_flag_clear(QUEUE_FLAG_STOPPED, q);
 	__blk_run_queue(q);


Patches currently in stable-queue which might be from bart.vanassche@wdc.com are

queue-4.4/block-relax-a-check-in-blk_start_queue.patch