block: warn if sharing request queue across gendisks

Now that the remaining drivers have been converted to one request queue
per gendisk, let's warn if a request queue gets registered more than
once. This will catch future drivers which might do it inadvertently or
any old drivers that I may have missed.

Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 7f090dd15ca6e93d0a7e7beffae149c354b57184..833fb7f9ce9de242fe77183278d015ed9b6eb2a5 100644 (file)
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -871,6 +871,11 @@ int blk_register_queue(struct gendisk *disk)
        if (WARN_ON(!q))
                return -ENXIO;
 
+       WARN_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags),
+                 "%s is registering an already registered queue\n",
+                 kobject_name(&dev->kobj));
+       queue_flag_set_unlocked(QUEUE_FLAG_REGISTERED, q);
+
        /*
         * SCSI probing may synchronously create and destroy a lot of
         * request_queues for non-existent devices.  Shutting down a fully
@@ -931,6 +936,8 @@ void blk_unregister_queue(struct gendisk *disk)
        if (WARN_ON(!q))
                return;
 
+       queue_flag_clear_unlocked(QUEUE_FLAG_REGISTERED, q);
+
        if (q->mq_ops)
                blk_mq_unregister_dev(disk_to_dev(disk), q);
 

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1a7dc42a89184696a56918cd6a46e6cb93abb555..a2dc6b390d4839e224553333822c4c37ae64a5bd 100644 (file)
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -617,6 +617,7 @@ struct request_queue {
 #define QUEUE_FLAG_STATS       27      /* track rq completion times */
 #define QUEUE_FLAG_RESTART     28      /* queue needs restart at completion */
 #define QUEUE_FLAG_POLL_STATS  29      /* collecting stats for hybrid polling */
+#define QUEUE_FLAG_REGISTERED  30      /* queue has been registered to a disk */
 
 #define QUEUE_FLAG_DEFAULT     ((1 << QUEUE_FLAG_IO_STAT) |            \
                                 (1 << QUEUE_FLAG_STACKABLE)    |       \