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ublk: simplify aborting ublk request

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Now ublk_abort_queue() is moved to ublk char device release handler,
meantime our request queue is "quiesced" because either ->canceling was
set from uring_cmd cancel function or all IOs are inflight and can't be
completed by ublk server, things becomes easy much:

- all uring_cmd are done, so we needn't to mark io as UBLK_IO_FLAG_ABORTED
for handling completion from uring_cmd

- ublk char device is closed, no one can hold IO request reference any more,
so we can simply complete this request or requeue it for ublk_nosrv_should_reissue_outstanding.

Reviewed-by: Uday Shankar <ushankar@purestorage.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250416035444.99569-8-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei
2025-04-16 11:54:41 +08:00
committed by Jens Axboe
parent 736b005b41
commit e63d2228ef
1 changed files with 20 additions and 62 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
drivers/block/ublk_drv.c
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@@ -122,15 +122,6 @@ struct ublk_uring_cmd_pdu {
*/
#define UBLK_IO_FLAG_OWNED_BY_SRV 0x02
/*
* IO command is aborted, so this flag is set in case of
* !UBLK_IO_FLAG_ACTIVE.
*
* After this flag is observed, any pending or new incoming request
* associated with this io command will be failed immediately
*/
#define UBLK_IO_FLAG_ABORTED 0x04
/*
* UBLK_IO_FLAG_NEED_GET_DATA is set because IO command requires
* get data buffer address from ublksrv.
@@ -1083,12 +1074,6 @@ static inline void __ublk_complete_rq(struct request *req)
unsigned int unmapped_bytes;
blk_status_t res = BLK_STS_OK;
/* called from ublk_abort_queue() code path */
if (io->flags & UBLK_IO_FLAG_ABORTED) {
res = BLK_STS_IOERR;
goto exit;
}
/* failed read IO if nothing is read */
if (!io->res && req_op(req) == REQ_OP_READ)
io->res = -EIO;
@@ -1138,47 +1123,6 @@ static void ublk_complete_rq(struct kref *ref)
__ublk_complete_rq(req);
}
static void ublk_do_fail_rq(struct request *req)
{
struct ublk_queue *ubq = req->mq_hctx->driver_data;
if (ublk_nosrv_should_reissue_outstanding(ubq->dev))
blk_mq_requeue_request(req, false);
else
__ublk_complete_rq(req);
}
static void ublk_fail_rq_fn(struct kref *ref)
{
struct ublk_rq_data *data = container_of(ref, struct ublk_rq_data,
ref);
struct request *req = blk_mq_rq_from_pdu(data);
ublk_do_fail_rq(req);
}
/*
* Since ublk_rq_task_work_cb always fails requests immediately during
* exiting, __ublk_fail_req() is only called from abort context during
* exiting. So lock is unnecessary.
*
* Also aborting may not be started yet, keep in mind that one failed
* request may be issued by block layer again.
*/
static void __ublk_fail_req(struct ublk_queue *ubq, struct ublk_io *io,
struct request *req)
{
WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_ACTIVE);
if (ublk_need_req_ref(ubq)) {
struct ublk_rq_data *data = blk_mq_rq_to_pdu(req);
kref_put(&data->ref, ublk_fail_rq_fn);
} else {
ublk_do_fail_rq(req);
}
}
static void ubq_complete_io_cmd(struct ublk_io *io, int res,
unsigned issue_flags)
{
@@ -1667,10 +1611,26 @@ static void ublk_commit_completion(struct ublk_device *ub,
ublk_put_req_ref(ubq, req);
}
static void __ublk_fail_req(struct ublk_queue *ubq, struct ublk_io *io,
struct request *req)
{
WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_ACTIVE);
if (ublk_nosrv_should_reissue_outstanding(ubq->dev))
blk_mq_requeue_request(req, false);
else {
io->res = -EIO;
__ublk_complete_rq(req);
}
}
/*
* Called from ubq_daemon context via cancel fn, meantime quiesce ublk
* blk-mq queue, so we are called exclusively with blk-mq and ubq_daemon
* context, so everything is serialized.
* Called from ublk char device release handler, when any uring_cmd is
* done, meantime request queue is "quiesced" since all inflight requests
* can't be completed because ublk server is dead.
*
* So no one can hold our request IO reference any more, simply ignore the
* reference, and complete the request immediately
*/
static void ublk_abort_queue(struct ublk_device *ub, struct ublk_queue *ubq)
{
@@ -1687,10 +1647,8 @@ static void ublk_abort_queue(struct ublk_device *ub, struct ublk_queue *ubq)
* will do it
*/
rq = blk_mq_tag_to_rq(ub->tag_set.tags[ubq->q_id], i);
if (rq && blk_mq_request_started(rq)) {
io->flags |= UBLK_IO_FLAG_ABORTED;
if (rq && blk_mq_request_started(rq))
__ublk_fail_req(ubq, io, rq);
}
}
}
}