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ublk: kill queuing request by task_work_add

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task_work_add() is used from early ublk development stage for handling
request in batch. However, since commit 7d4a93176e01 ("ublk_drv: don't
forward io commands in reserve order"), we can get similar batch
processing with io_uring_cmd_complete_in_task(), and similar performance
data is observed between task_work_add() and
io_uring_cmd_complete_in_task().

Meantime we can kill one fast code path, which is actually seldom used
given it is common to build ublk driver as module.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230519065030.351216-2-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2023-05-19 14:50:24 +08:00 committed by Jens Axboe
parent 9a67aa52a4
commit 29dc5d0661
1 changed files with 2 additions and 38 deletions
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40
drivers/block/ublk_drv.c
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@ -62,7 +62,6 @@
struct ublk_rq_data {
struct llist_node node;
struct callback_head work;
};
struct ublk_uring_cmd_pdu {
@ -290,14 +289,6 @@ static int ublk_apply_params(struct ublk_device *ub)
return 0;
}
static inline bool ublk_can_use_task_work(const struct ublk_queue *ubq)
{
if (IS_BUILTIN(CONFIG_BLK_DEV_UBLK) &&
!(ubq->flags & UBLK_F_URING_CMD_COMP_IN_TASK))
return true;
return false;
}
static inline bool ublk_need_get_data(const struct ublk_queue *ubq)
{
return ubq->flags & UBLK_F_NEED_GET_DATA;
@ -852,17 +843,6 @@ static void ublk_rq_task_work_cb(struct io_uring_cmd *cmd, unsigned issue_flags)
ublk_forward_io_cmds(ubq, issue_flags);
}
static void ublk_rq_task_work_fn(struct callback_head *work)
{
struct ublk_rq_data *data = container_of(work,
struct ublk_rq_data, work);
struct request *req = blk_mq_rq_from_pdu(data);
struct ublk_queue *ubq = req->mq_hctx->driver_data;
unsigned issue_flags = IO_URING_F_UNLOCKED;
ublk_forward_io_cmds(ubq, issue_flags);
}
static void ublk_queue_cmd(struct ublk_queue *ubq, struct request *rq)
{
struct ublk_rq_data *data = blk_mq_rq_to_pdu(rq);
@ -886,10 +866,6 @@ static void ublk_queue_cmd(struct ublk_queue *ubq, struct request *rq)
*/
if (unlikely(io->flags & UBLK_IO_FLAG_ABORTED)) {
ublk_abort_io_cmds(ubq);
} else if (ublk_can_use_task_work(ubq)) {
if (task_work_add(ubq->ubq_daemon, &data->work,
TWA_SIGNAL_NO_IPI))
ublk_abort_io_cmds(ubq);
} else {
struct io_uring_cmd *cmd = io->cmd;
struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);
@ -961,19 +937,9 @@ static int ublk_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data,
return 0;
}
static int ublk_init_rq(struct blk_mq_tag_set *set, struct request *req,
unsigned int hctx_idx, unsigned int numa_node)
{
struct ublk_rq_data *data = blk_mq_rq_to_pdu(req);
init_task_work(&data->work, ublk_rq_task_work_fn);
return 0;
}
static const struct blk_mq_ops ublk_mq_ops = {
.queue_rq = ublk_queue_rq,
.init_hctx = ublk_init_hctx,
.init_request = ublk_init_rq,
.timeout = ublk_timeout,
};
@ -1813,10 +1779,8 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
*/
ub->dev_info.flags &= UBLK_F_ALL;
if (!IS_BUILTIN(CONFIG_BLK_DEV_UBLK))
ub->dev_info.flags |= UBLK_F_URING_CMD_COMP_IN_TASK;
ub->dev_info.flags |= UBLK_F_CMD_IOCTL_ENCODE;
ub->dev_info.flags |= UBLK_F_CMD_IOCTL_ENCODE |
UBLK_F_URING_CMD_COMP_IN_TASK;
/* We are not ready to support zero copy */
ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;