scsi: do quiesce for enclosure driver

hulk inclusion
category: bugfix
bugzilla: 46860

--------------------------------

Drivers (such as scsi enclosure) will not call blk_register_queue()
to do initialize for request_queue. And we rely on driver self
to deal with the race in that case when cleanup queue.

But, some self-developed drivers cannot deal the race. To avoid
null pointer reference as following, we do quiesce in kernel.

[67760.308034] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
...
[67760.308069] pc : blk_mq_do_dispatch_sched+0x94/0x130
[67760.308072] lr : blk_mq_sched_dispatch_requests+0x128/0x1f0
[67760.308072] sp : ffff0000b2bb3ca0
[67760.308073] x29: ffff0000b2bb3ca0 x28: 0000000000000000
[67760.308075] x27: 0000000000000000 x26: ffff00008128a000
[67760.308076] x25: ffff8042b13e9700 x24: 0000000000000000
[67760.308077] x23: ffff0000b2bb3cf8 x22: ffff8042b2976808
[67760.308078] x21: ffff0000b2bb3d58 x20: ffff00008128a000
[67760.308079] x19: ffff8042b2976800 x18: 0000000000000000
[67760.308080] x17: 0000000000000000 x16: 0000000000000000
[67760.308081] x15: 0000000000000000 x14: 0000000000000000
[67760.308082] x13: 0000000000000000 x12: 0000000000000000
[67760.308084] x11: ffff800040801004 x10: ffff80004080100c
[67760.308085] x9 : 0000000000000060 x8 : ffff809e58f7e500
[67760.308087] x7 : 0000000000000000 x6 : 00000000ffffffff
[67760.308088] x5 : ffff000080ab7550 x4 : ffff80418e84ec80
[67760.308089] x3 : ffff0000815d7f10 x2 : 94e133dc71839c00
[67760.308090] x1 : 0000000000000000 x0 : ffff00008128a748
[67760.308091] Call trace:
[67760.308093]  blk_mq_do_dispatch_sched+0x94/0x130
[67760.308095]  blk_mq_sched_dispatch_requests+0x128/0x1f0
[67760.308096]  __blk_mq_run_hw_queue+0x98/0x138
[67760.308097]  blk_mq_run_work_fn+0x28/0x38
Signed-off-by: NYufen Yu <yuyufen@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

block/blk-core.c

@@ -791,9 +791,12 @@ void blk_cleanup_queue(struct request_queue *q)
 	 * from more than one contexts.
 	 *
 	 * We rely on driver to deal with the race in case that queue
-	 * initialization isn't done.
+	 * initialization isn't done. If driver cannot deal the race,
+	 * we try to call quiesce in kernel for these drivers that have
+	 * set QUEUE_FLAG_FORECE_QUIESCE flag.
 	 */
-	if (q->mq_ops && blk_queue_init_done(q))
+	if (q->mq_ops && (blk_queue_init_done(q) ||
+			test_bit(QUEUE_FLAG_FORECE_QUIESCE, &q->queue_flags)))
 		blk_mq_quiesce_queue(q);
 
 	/* for synchronous bio-based driver finish in-flight integrity i/o */

drivers/scsi/scsi_scan.c

@@ -844,6 +844,10 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 			*bflags |= BLIST_NOREPORTLUN;
 	}
 
+	if (sdev->type == TYPE_ENCLOSURE)
+		set_bit(QUEUE_FLAG_FORECE_QUIESCE,
+				&sdev->request_queue->queue_flags);
+
 	/*
 	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
 	 * spec says: The device server is capable of supporting the

include/linux/blkdev.h

@@ -720,6 +720,7 @@ struct request_queue {
 #define QUEUE_FLAG_REGISTERED  26	/* queue has been registered to a disk */
 #define QUEUE_FLAG_SCSI_PASSTHROUGH 27	/* queue supports SCSI commands */
 #define QUEUE_FLAG_QUIESCED    28	/* queue has been quiesced */
+#define QUEUE_FLAG_FORECE_QUIESCE 29 /* force quiesce when cleanup queue */
 
 #define QUEUE_FLAG_DEFAULT	((1 << QUEUE_FLAG_IO_STAT) |		\
 				 (1 << QUEUE_FLAG_SAME_COMP)	|	\