On 5/20/21 6:22 AM, Damien Le Moal wrote:
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 <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
---
  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
  };
I would have merged this with the patch actually using it, but this is probably a personal preference.

Reviewed-by: Hannes Reinecke <[email protected]>

Cheers,

Hannes
--
Dr. Hannes Reinecke                Kernel Storage Architect
[email protected]                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer


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