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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Damien Le Moal <damien.lemoal@wdc.com>,
        Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>,
        Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
        Himanshu Madhani <himanshu.madhani@oracle.com>,
        Jens Axboe <axboe@kernel.dk>,
        Mike Snitzer <snitzer@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.12 059/242] block: introduce BIO_ZONE_WRITE_LOCKED bio flag
Date:   Thu, 15 Jul 2021 20:37:01 +0200
Message-Id: <20210715182602.873658509@linuxfoundation.org>
In-Reply-To: <20210715182551.731989182@linuxfoundation.org>
References: <20210715182551.731989182@linuxfoundation.org>
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From: Damien Le Moal <damien.lemoal@wdc.com>

[ Upstream commit 9ffbbb435d8f566a0924ce4b5dc7fc1bceb6dbf8 ]

Introduce the BIO flag BIO_ZONE_WRITE_LOCKED to indicate that a BIO owns
the write lock of the zone it is targeting. This is the counterpart of
the struct request flag RQF_ZONE_WRITE_LOCKED.

This new BIO flag is reserved for now for zone write locking control
for device mapper targets exposing a zoned block device. Since in this
case, the lock flag must not be propagated to the struct request that
will be used to process the BIO, a BIO private flag is used rather than
changing the RQF_ZONE_WRITE_LOCKED request flag into a common REQ_XXX
flag that could be used for both BIO and request. This avoids conflicts
down the stack with the block IO scheduler zone write locking
(in mq-deadline).

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/blk_types.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index db026b6ec15a..e5cf12f102a2 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -304,6 +304,7 @@ enum {
 	BIO_CGROUP_ACCT,	/* has been accounted to a cgroup */
 	BIO_TRACKED,		/* set if bio goes through the rq_qos path */
 	BIO_REMAPPED,
+	BIO_ZONE_WRITE_LOCKED,	/* Owns a zoned device zone write lock */
 	BIO_FLAG_LAST
 };
 
-- 
2.30.2