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

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 <[email protected]> know about it.

From: Bart Van Assche <[email protected]>
Date: Thu, 17 Aug 2017 13:12:44 -0700
Subject: block: Relax a check in blk_start_queue()

From: Bart Van Assche <[email protected]>

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

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

@@ -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 [email protected] are

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