[RFC PATCH V2 4/6] ublk_drv: requeue rqs with recovery feature enabled

ZiyangZhang
2022-08-31T15:54:42Z

With recovery feature enabled, in ublk_queue_rq or task work
(in exit_task_work or fallback wq), we requeue rqs instead of
ending(aborting) them.

No matter recovery feature is enabled or disabled, schedule monitor work
immediately after detecting a crash so it can find out the crash and
do aborting/recovery mechanism.

Signed-off-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com>
---
drivers/block/ublk_drv.c | 25 ++++++++++++++++++++++---
1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 0c3d32e8d686..296b9d80f003 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -690,7 +690,16 @@ static inline void __ublk_rq_task_work(struct request *req)
* (2) current->flags & PF_EXITING.
*/
if (unlikely(current != ubq->ubq_daemon || current->flags & PF_EXITING)) {
- blk_mq_end_request(req, BLK_STS_IOERR);
+ pr_devel("%s: %s q_id %d tag %d io_flags %x.\n", __func__,
+ (ublk_can_use_recovery(ub)) ? "requeue" : "abort",
+ ubq->q_id, req->tag, io->flags);
+
+ if (ublk_can_use_recovery(ub)) {
+ /* We cannot process this req so just requeue it. */
+ blk_mq_requeue_request(req, false);
+ } else {
+ blk_mq_end_request(req, BLK_STS_IOERR);
+ }
mod_delayed_work(system_wq, &ub->monitor_work, 0);
return;
}
@@ -770,6 +779,7 @@ static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
{
struct ublk_queue *ubq = hctx->driver_data;
struct request *rq = bd->rq;
+ struct ublk_io *io = &ubq->ios[rq->tag];
blk_status_t res;

/* fill iod to slot in io cmd buffer */
@@ -781,8 +791,18 @@ static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,

if (unlikely(ubq_daemon_is_dying(ubq))) {
fail:
+ pr_devel("%s: %s q_id %d tag %d io_flags %x.\n", __func__,
+ (ublk_can_use_recovery(ubq->dev)) ? "requeue" : "abort",
+ ubq->q_id, rq->tag, io->flags);
+
mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0);
- return BLK_STS_IOERR;
+ if (ublk_can_use_recovery(ubq->dev)) {
+ /* We cannot process this rq so just requeue it. */
+ blk_mq_requeue_request(rq, false);
+ return BLK_STS_OK;
+ } else {
+ return BLK_STS_IOERR;
+ }
}

if (ublk_can_use_task_work(ubq)) {
@@ -793,7 +813,6 @@ static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx,
if (task_work_add(ubq->ubq_daemon, &data->work, notify_mode))
goto fail;
} else {
- struct ublk_io *io = &ubq->ios[rq->tag];
struct io_uring_cmd *cmd = io->cmd;
struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd);

--
2.27.0