From: Liu Xiaodong xiaodong.liu@intel.com
[ Upstream commit 2f1e07dda1e1310873647abc40bbc49eaf3b10e3 ]
Currently, uring_cmd with UBLK_IO_FETCH_REQ or UBLK_IO_COMMIT_AND_FETCH_REQ is always checked whether userspace server has provided IO buffer even flag UBLK_F_NEED_GET_DATA is configured.
This is a excessive check. If UBLK_F_NEED_GET_DATA is configured, FETCH_RQ doesn't need to provide IO buffer; COMMIT_AND_FETCH_REQ also doesn't need to do that if the IO type is not READ.
Check ub_cmd->addr together with ublk_need_get_data() and IO type in ublk_ch_uring_cmd().
With this fix, userspace server doesn't need to preserve buffers for every ublk_io when flag UBLK_F_NEED_GET_DATA is configured, in order to save memory.
Signed-off-by: Liu Xiaodong xiaodong.liu@intel.com Fixes: c86019ff75c1 ("ublk_drv: add support for UBLK_IO_NEED_GET_DATA") Reviewed-by: Ming Lei ming.lei@redhat.com Link: https://lore.kernel.org/r/20230210141356.112321-1-xiaodong.liu@intel.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/ublk_drv.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 450bd54fd0061..4aec9be0ab77e 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -1206,6 +1206,7 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) u32 cmd_op = cmd->cmd_op; unsigned tag = ub_cmd->tag; int ret = -EINVAL; + struct request *req;
pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n", __func__, cmd->cmd_op, ub_cmd->q_id, tag, @@ -1256,8 +1257,8 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) */ if (io->flags & UBLK_IO_FLAG_OWNED_BY_SRV) goto out; - /* FETCH_RQ has to provide IO buffer */ - if (!ub_cmd->addr) + /* FETCH_RQ has to provide IO buffer if NEED GET DATA is not enabled */ + if (!ub_cmd->addr && !ublk_need_get_data(ubq)) goto out; io->cmd = cmd; io->flags |= UBLK_IO_FLAG_ACTIVE; @@ -1266,8 +1267,12 @@ static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) ublk_mark_io_ready(ub, ubq); break; case UBLK_IO_COMMIT_AND_FETCH_REQ: - /* FETCH_RQ has to provide IO buffer */ - if (!ub_cmd->addr) + req = blk_mq_tag_to_rq(ub->tag_set.tags[ub_cmd->q_id], tag); + /* + * COMMIT_AND_FETCH_REQ has to provide IO buffer if NEED GET DATA is + * not enabled or it is Read IO. + */ + if (!ub_cmd->addr && (!ublk_need_get_data(ubq) || req_op(req) == REQ_OP_READ)) goto out; if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)) goto out;