From 1b0cab327e060ccf397ae634a34c84dd1d4d2bb2 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 26 Nov 2024 11:21:36 +0100
Subject: [PATCH] mq-deadline: don't call req_get_ioprio from the I/O
completion handler
req_get_ioprio looks at req->bio to find the I/O priority, which is not
set when completing bios that the driver fully iterated through.
Stash away the dd_per_prio in the elevator private data instead of looking
it up again to optimize the code a bit while fixing the regression from
removing the per-request ioprio value.
Fixes: 6975c1a486a4 ("block: remove the ioprio field from struct request")
Reported-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Reported-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Tested-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20241126102136.619067-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
block/mq-deadline.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index acdc28756d9d7..91b3789f710e7 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -685,10 +685,9 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
prio = ioprio_class_to_prio[ioprio_class];
per_prio = &dd->per_prio[prio];
- if (!rq->elv.priv[0]) {
+ if (!rq->elv.priv[0])
per_prio->stats.inserted++;
- rq->elv.priv[0] = (void *)(uintptr_t)1;
- }
+ rq->elv.priv[0] = per_prio;
if (blk_mq_sched_try_insert_merge(q, rq, free))
return;
@@ -753,18 +752,14 @@ static void dd_prepare_request(struct request *rq)
*/
static void dd_finish_request(struct request *rq)
{
- struct request_queue *q = rq->q;
- struct deadline_data *dd = q->elevator->elevator_data;
- const u8 ioprio_class = dd_rq_ioclass(rq);
- const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
- struct dd_per_prio *per_prio = &dd->per_prio[prio];
+ struct dd_per_prio *per_prio = rq->elv.priv[0];
/*
* The block layer core may call dd_finish_request() without having
* called dd_insert_requests(). Skip requests that bypassed I/O
* scheduling. See also blk_mq_request_bypass_insert().
*/
- if (rq->elv.priv[0])
+ if (per_prio)
atomic_inc(&per_prio->stats.completed);
}
--
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