linux-kernel - [PATCH V2] mmc: block: Fix in_flight[issue

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Date:   Wed, 2 Aug 2023 10:30:23 +0800
From:   Yunlong Xing <yunlong.xing@...soc.com>
To:     <ulf.hansson@...aro.org>, <adrian.hunter@...el.com>,
        <CLoehle@...erstone.com>, <brauner@...nel.org>, <hare@...e.de>,
        <asuk4.q@...il.com>, <avri.altman@....com>, <beanhuo@...ron.com>
CC:     <linus.walleij@...aro.org>, <linux-mmc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <stable@...r.kernel.org>,
        <hongyu.jin@...soc.com>, <zhiguo.niu@...soc.com>,
        <yunlong.xing23@...il.com>, <yibin.ding@...soc.com>,
        <dongliang.cui@...soc.com>
Subject: [PATCH V2] mmc: block: Fix in_flight[issue_type] value error

From: Yibin Ding <yibin.ding@...soc.com>

For a completed request, after the mmc_blk_mq_complete_rq(mq, req)
function is executed, the bitmap_tags corresponding to the
request will be cleared, that is, the request will be regarded as
idle. If the request is acquired by a different type of process at
this time, the issue_type of the request may change. It further
caused the value of mq->in_flight[issue_type] to be abnormal,
and a large number of requests could not be sent.

p1:					      p2:
mmc_blk_mq_complete_rq
  blk_mq_free_request
					      blk_mq_get_request
					        blk_mq_rq_ctx_init
mmc_blk_mq_dec_in_flight
  mmc_issue_type(mq, req)

This strategy can ensure the consistency of issue_type
before and after executing mmc_blk_mq_complete_rq.

Fixes: 81196976ed94 ("mmc: block: Add blk-mq support")
Cc: stable@...r.kernel.org
Signed-off-by: Yibin Ding <yibin.ding@...soc.com>
Acked-by: Adrian Hunter <adrian.hunter@...el.com>
---
changes of v2: Sort local declarations in descending order of
line length
---
 drivers/mmc/core/block.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index f701efb1fa78..b6f4be25b31b 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -2097,14 +2097,14 @@ static void mmc_blk_mq_poll_completion(struct mmc_queue *mq,
 	mmc_blk_urgent_bkops(mq, mqrq);
 }
 
-static void mmc_blk_mq_dec_in_flight(struct mmc_queue *mq, struct request *req)
+static void mmc_blk_mq_dec_in_flight(struct mmc_queue *mq, enum mmc_issue_type issue_type)
 {
 	unsigned long flags;
 	bool put_card;
 
 	spin_lock_irqsave(&mq->lock, flags);
 
-	mq->in_flight[mmc_issue_type(mq, req)] -= 1;
+	mq->in_flight[issue_type] -= 1;
 
 	put_card = (mmc_tot_in_flight(mq) == 0);
 
@@ -2117,6 +2117,7 @@ static void mmc_blk_mq_dec_in_flight(struct mmc_queue *mq, struct request *req)
 static void mmc_blk_mq_post_req(struct mmc_queue *mq, struct request *req,
 				bool can_sleep)
 {
+	enum mmc_issue_type issue_type = mmc_issue_type(mq, req);
 	struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
 	struct mmc_request *mrq = &mqrq->brq.mrq;
 	struct mmc_host *host = mq->card->host;
@@ -2136,7 +2137,7 @@ static void mmc_blk_mq_post_req(struct mmc_queue *mq, struct request *req,
 			blk_mq_complete_request(req);
 	}
 
-	mmc_blk_mq_dec_in_flight(mq, req);
+	mmc_blk_mq_dec_in_flight(mq, issue_type);
 }
 
 void mmc_blk_mq_recovery(struct mmc_queue *mq)
-- 
2.25.1