block: remove QUEUE_FLAG_DEAD

Disallow setting the blk-mq state on any queue that is already dying as setting the state even then is a bad idea, and remove the now unused QUEUE_FLAG_DEAD flag. Signed-off-by: Christoph Hellwig <[email protected]> Reviewed-by: Hannes Reinecke <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jens Axboe <[email protected]>
kawasaki · Jun 28, 2022 · 1f90307 · 1f90307
1 parent e8b58ef
commit 1f90307
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Showing 3 changed files with 3 additions and 10 deletions.
diff --git a/block/blk-core.c b/block/blk-core.c
@@ -313,9 +313,6 @@ void blk_cleanup_queue(struct request_queue *q)
 	 * after draining finished.
 	 */
 	blk_freeze_queue(q);
-
-	blk_queue_flag_set(QUEUE_FLAG_DEAD, q);
-
 	blk_sync_queue(q);
 	if (queue_is_mq(q)) {
 		blk_mq_cancel_work_sync(q);

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
@@ -116,7 +116,6 @@ static const char *const blk_queue_flag_name[] = {
 	QUEUE_FLAG_NAME(NOXMERGES),
 	QUEUE_FLAG_NAME(ADD_RANDOM),
 	QUEUE_FLAG_NAME(SAME_FORCE),
-	QUEUE_FLAG_NAME(DEAD),
 	QUEUE_FLAG_NAME(INIT_DONE),
 	QUEUE_FLAG_NAME(STABLE_WRITES),
 	QUEUE_FLAG_NAME(POLL),
@@ -151,11 +150,10 @@ static ssize_t queue_state_write(void *data, const char __user *buf,
 	char opbuf[16] = { }, *op;
 
 	/*
-	 * The "state" attribute is removed after blk_cleanup_queue() has called
-	 * blk_mq_free_queue(). Return if QUEUE_FLAG_DEAD has been set to avoid
-	 * triggering a use-after-free.
+	 * The "state" attribute is removed when the queue is removed.  Don't
+	 * allow setting the state on a dying queue to avoid a use-after-free.
 	 */
-	if (blk_queue_dead(q))
+	if (blk_queue_dying(q))
 		return -ENOENT;
 
 	if (count >= sizeof(opbuf)) {

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
@@ -564,7 +564,6 @@ struct request_queue {
 #define QUEUE_FLAG_NOXMERGES	9	/* No extended merges */
 #define QUEUE_FLAG_ADD_RANDOM	10	/* Contributes to random pool */
 #define QUEUE_FLAG_SAME_FORCE	12	/* force complete on same CPU */
-#define QUEUE_FLAG_DEAD		13	/* queue tear-down finished */
 #define QUEUE_FLAG_INIT_DONE	14	/* queue is initialized */
 #define QUEUE_FLAG_STABLE_WRITES 15	/* don't modify blks until WB is done */
 #define QUEUE_FLAG_POLL		16	/* IO polling enabled if set */
@@ -592,7 +591,6 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
 #define blk_queue_stopped(q)	test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
 #define blk_queue_dying(q)	test_bit(QUEUE_FLAG_DYING, &(q)->queue_flags)
 #define blk_queue_has_srcu(q)	test_bit(QUEUE_FLAG_HAS_SRCU, &(q)->queue_flags)
-#define blk_queue_dead(q)	test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
 #define blk_queue_init_done(q)	test_bit(QUEUE_FLAG_INIT_DONE, &(q)->queue_flags)
 #define blk_queue_nomerges(q)	test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
 #define blk_queue_noxmerges(q)	\