[PATCH v4 04/11] block: Introduce blk_rq_is_seq_zoned_write()

[Bart Van Assche <bvanassche@xxxxxxx>]

Introduce the function blk_rq_is_seq_zoned_write(). This function will
be used in later patches to preserve the order of zoned writes that
require write serialization.

This patch includes an optimization: instead of using
rq->q->disk->part0->bd_queue to check whether or not the queue is
associated with a zoned block device, use rq->q->disk->queue.

Cc: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
 block/blk-zoned.c      | 17 +++++++++++++----
 include/linux/blk-mq.h |  6 ++++++
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 835d9e937d4d..4f44b74ba4df 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -52,6 +52,18 @@ const char *blk_zone_cond_str(enum blk_zone_cond zone_cond)
 }
 EXPORT_SYMBOL_GPL(blk_zone_cond_str);
 
+/**
+ * blk_rq_is_seq_zoned_write() - Check if @rq requires write serialization.
+ * @rq: Request to examine.
+ *
+ * Note: REQ_OP_ZONE_APPEND requests do not require serialization.
+ */
+bool blk_rq_is_seq_zoned_write(struct request *rq)
+{
+	return op_is_zoned_write(req_op(rq)) && blk_rq_zone_is_seq(rq);
+}
+EXPORT_SYMBOL_GPL(blk_rq_is_seq_zoned_write);
+
 /*
  * Return true if a request is a write requests that needs zone write locking.
  */
@@ -60,10 +72,7 @@ bool blk_req_needs_zone_write_lock(struct request *rq)
 	if (!rq->q->disk->seq_zones_wlock)
 		return false;
 
-	if (bdev_op_is_zoned_write(rq->q->disk->part0, req_op(rq)))
-		return blk_rq_zone_is_seq(rq);
-
-	return false;
+	return blk_rq_is_seq_zoned_write(rq);
 }
 EXPORT_SYMBOL_GPL(blk_req_needs_zone_write_lock);
 
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 06caacd77ed6..e498b85bc470 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -1164,6 +1164,7 @@ static inline unsigned int blk_rq_zone_is_seq(struct request *rq)
 	return disk_zone_is_seq(rq->q->disk, blk_rq_pos(rq));
 }
 
+bool blk_rq_is_seq_zoned_write(struct request *rq);
 bool blk_req_needs_zone_write_lock(struct request *rq);
 bool blk_req_zone_write_trylock(struct request *rq);
 void __blk_req_zone_write_lock(struct request *rq);
@@ -1194,6 +1195,11 @@ static inline bool blk_req_can_dispatch_to_zone(struct request *rq)
 	return !blk_req_zone_is_write_locked(rq);
 }
 #else /* CONFIG_BLK_DEV_ZONED */
+static inline bool blk_rq_is_seq_zoned_write(struct request *rq)
+{
+	return false;
+}
+
 static inline bool blk_req_needs_zone_write_lock(struct request *rq)
 {
 	return false;