[PATCH v6 4/5] null_blk: pass transfer size to null_handle_rq()
From: Shin'ichiro Kawasaki <hidden>
Date: 2025-01-30 08:27:14
Subsystem:
block layer, the rest · Maintainers:
Jens Axboe, Linus Torvalds
As preparation to support partial data transfer, add a new argument to null_handle_rq() to pass the number of sectors to transfer. While at it, rename the function from null_handle_rq to null_handle_data_transfer. This commit does not change the behavior. Reviewed-by: Damien Le Moal <dlemoal@kernel.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Johannes Thumshirn <redacted> Signed-off-by: Shin'ichiro Kawasaki <redacted> --- drivers/block/null_blk/main.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 87037cb375c9..802576698812 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c@@ -1263,25 +1263,37 @@ static int null_transfer(struct nullb *nullb, struct page *page, return err; } -static blk_status_t null_handle_rq(struct nullb_cmd *cmd) +/* + * Transfer data for the given request. The transfer size is capped with the + * nr_sectors argument. + */ +static blk_status_t null_handle_data_transfer(struct nullb_cmd *cmd, + sector_t nr_sectors) { struct request *rq = blk_mq_rq_from_pdu(cmd); struct nullb *nullb = cmd->nq->dev->nullb; int err = 0; unsigned int len; sector_t sector = blk_rq_pos(rq); + unsigned int max_bytes = nr_sectors << SECTOR_SHIFT; + unsigned int transferred_bytes = 0; struct req_iterator iter; struct bio_vec bvec; spin_lock_irq(&nullb->lock); rq_for_each_segment(bvec, rq, iter) { len = bvec.bv_len; + if (transferred_bytes + len > max_bytes) + len = max_bytes - transferred_bytes; err = null_transfer(nullb, bvec.bv_page, len, bvec.bv_offset, op_is_write(req_op(rq)), sector, rq->cmd_flags & REQ_FUA); if (err) break; sector += len >> SECTOR_SHIFT; + transferred_bytes += len; + if (transferred_bytes >= max_bytes) + break; } spin_unlock_irq(&nullb->lock);
@@ -1333,7 +1345,7 @@ blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd, enum req_op op, if (op == REQ_OP_DISCARD) return null_handle_discard(dev, sector, nr_sectors); - return null_handle_rq(cmd); + return null_handle_data_transfer(cmd, nr_sectors); } static void nullb_zero_read_cmd_buffer(struct nullb_cmd *cmd)
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2.47.0