blk-zoned: Improve the queue reference count strategy documentation

For the blk_queue_exit() calls, document where the corresponding code can
be found that increases q->q_usage_counter.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20241217210310.645966-4-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 954724a2e3c650bfa16af91fe2d52e2418a14fa8..7876a6458022503cf903181c91dee16e1fe37825 100644 (file)
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -582,6 +582,7 @@ static inline void blk_zone_wplug_bio_io_error(struct blk_zone_wplug *zwplug,
        bio_clear_flag(bio, BIO_ZONE_WRITE_PLUGGING);
        bio_io_error(bio);
        disk_put_zone_wplug(zwplug);
+       /* Drop the reference taken by disk_zone_wplug_add_bio(() */
        blk_queue_exit(q);
 }
 
@@ -893,10 +894,7 @@ void blk_zone_write_plug_init_request(struct request *req)
                        break;
                }
 
-               /*
-                * Drop the extra reference on the queue usage we got when
-                * plugging the BIO and advance the write pointer offset.
-                */
+               /* Drop the reference taken by disk_zone_wplug_add_bio(). */
                blk_queue_exit(q);
                zwplug->wp_offset += bio_sectors(bio);