[PATCH v6 3/6] block: Introduce blk_queue_get_max_write_zeroes_sectors()

Kirill Tkhai
2020-02-10T09:34:31Z

This introduces a new primitive, which returns max sectors
for REQ_OP_WRITE_ZEROES operation.
@op_flags is unused now, and it will be enabled in next patch.

Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
---
block/blk-core.c | 2 +-
block/blk-merge.c | 9 ++++++---
include/linux/blkdev.h | 8 +++++++-
3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 28a6d46eb982..c7387b0d69e5 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -949,7 +949,7 @@ generic_make_request_checks(struct bio *bio)
goto not_supported;
break;
case REQ_OP_WRITE_ZEROES:
- if (!q->limits.max_write_zeroes_sectors)
+ if (!blk_queue_get_max_write_zeroes_sectors(q, bio->bi_opf))
goto not_supported;
break;
default:
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 1534ed736363..467b292bc6e8 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -105,15 +105,18 @@ static struct bio *blk_bio_discard_split(struct request_queue *q,
static struct bio *blk_bio_write_zeroes_split(struct request_queue *q,
struct bio *bio, struct bio_set *bs, unsigned *nsegs)
{
+ unsigned int max_sectors;
+
+ max_sectors = blk_queue_get_max_write_zeroes_sectors(q, bio->bi_opf);
*nsegs = 0;

- if (!q->limits.max_write_zeroes_sectors)
+ if (!max_sectors)
return NULL;

- if (bio_sectors(bio) <= q->limits.max_write_zeroes_sectors)
+ if (bio_sectors(bio) <= max_sectors)
return NULL;

- return bio_split(bio, q->limits.max_write_zeroes_sectors, GFP_NOIO, bs);
+ return bio_split(bio, max_sectors, GFP_NOIO, bs);
}

static struct bio *blk_bio_write_same_split(struct request_queue *q,
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index f4ec7ae214ab..55a714161684 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -987,6 +987,12 @@ static inline struct bio_vec req_bvec(struct request *rq)
return mp_bvec_iter_bvec(rq->bio->bi_io_vec, rq->bio->bi_iter);
}

+static inline unsigned int blk_queue_get_max_write_zeroes_sectors(
+ struct request_queue *q, unsigned int op_flags)
+{
+ return q->limits.max_write_zeroes_sectors;
+}
+
static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
unsigned int op_flags)
{
@@ -1000,7 +1006,7 @@ static inline unsigned int blk_queue_get_max_sectors(struct request_queue *q,
return q->limits.max_write_same_sectors;

if (unlikely(op == REQ_OP_WRITE_ZEROES))
- return q->limits.max_write_zeroes_sectors;
+ return blk_queue_get_max_write_zeroes_sectors(q, op_flags);

return q->limits.max_sectors;
}