[PATCH v10 3/9] block: introduce blk_req_zone_write_trylock

From: Johannes Thumshirn <johannes.thumshirn@wdc.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>,
	linux-block <linux-block@vger.kernel.org>,
	Damien Le Moal <Damien.LeMoal@wdc.com>,
	Keith Busch <kbusch@kernel.org>,
	"linux-scsi @ vger . kernel . org" <linux-scsi@vger.kernel.org>,
	"Martin K . Petersen" <martin.petersen@oracle.com>,
	"linux-fsdevel @ vger . kernel . org"
	<linux-fsdevel@vger.kernel.org>,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>
Subject: [PATCH v10 3/9] block: introduce blk_req_zone_write_trylock
Date: Thu,  7 May 2020 01:11:39 +0900	[thread overview]
Message-ID: <20200506161145.9841-4-johannes.thumshirn@wdc.com> (raw)
In-Reply-To: <20200506161145.9841-1-johannes.thumshirn@wdc.com>

Introduce blk_req_zone_write_trylock(), which either grabs the write-lock
for a sequential zone or returns false, if the zone is already locked.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
---
 block/blk-zoned.c      | 14 ++++++++++++++
 include/linux/blkdev.h |  1 +
 2 files changed, 15 insertions(+)

diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index f87956e0dcaf..c822cfa7a102 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -82,6 +82,20 @@ bool blk_req_needs_zone_write_lock(struct request *rq)
 }
 EXPORT_SYMBOL_GPL(blk_req_needs_zone_write_lock);
 
+bool blk_req_zone_write_trylock(struct request *rq)
+{
+	unsigned int zno = blk_rq_zone_no(rq);
+
+	if (test_and_set_bit(zno, rq->q->seq_zones_wlock))
+		return false;
+
+	WARN_ON_ONCE(rq->rq_flags & RQF_ZONE_WRITE_LOCKED);
+	rq->rq_flags |= RQF_ZONE_WRITE_LOCKED;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(blk_req_zone_write_trylock);
+
 void __blk_req_zone_write_lock(struct request *rq)
 {
 	if (WARN_ON_ONCE(test_and_set_bit(blk_rq_zone_no(rq),
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 158641fbc7cd..d6e6ce3dc656 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1737,6 +1737,7 @@ extern int bdev_write_page(struct block_device *, sector_t, struct page *,
 
 #ifdef CONFIG_BLK_DEV_ZONED
 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);
 void __blk_req_zone_write_unlock(struct request *rq);
 
-- 
2.24.1

