From: Yu Kuai <yukuai3@huawei.com>
To: <axboe@kernel.dk>, <josef@toxicpanda.com>, <ming.lei@redhat.com>,
<hch@infradead.org>
Cc: <linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<nbd@other.debian.org>, <yukuai3@huawei.com>,
<yi.zhang@huawei.com>
Subject: [PATCH v5 4/6] blk-mq: export two symbols to get request by tag
Date: Thu, 9 Sep 2021 22:12:54 +0800 [thread overview]
Message-ID: <20210909141256.2606682-5-yukuai3@huawei.com> (raw)
In-Reply-To: <20210909141256.2606682-1-yukuai3@huawei.com>
nbd has a defect that blk_mq_tag_to_rq() might return a freed
request in nbd_read_stat(). We need a new mechanism if we want to
fix this in nbd driver, which is rather complicated.
Thus use blk_mq_find_and_get_req() to replace blk_mq_tag_to_rq(),
which can make sure the returned request is not freed, and then we
can do more checking while 'cmd->lock' is hold.
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
block/blk-mq-tag.c | 5 +++--
block/blk-mq.c | 1 +
include/linux/blk-mq.h | 3 +++
3 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 86f87346232a..b4f66b75b4d1 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -200,8 +200,8 @@ struct bt_iter_data {
bool reserved;
};
-static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
- unsigned int bitnr)
+struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
+ unsigned int bitnr)
{
struct request *rq;
unsigned long flags;
@@ -213,6 +213,7 @@ static struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
spin_unlock_irqrestore(&tags->lock, flags);
return rq;
}
+EXPORT_SYMBOL(blk_mq_find_and_get_req);
static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
{
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 08626cb0534c..5113aa3788a2 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -916,6 +916,7 @@ void blk_mq_put_rq_ref(struct request *rq)
else if (refcount_dec_and_test(&rq->ref))
__blk_mq_free_request(rq);
}
+EXPORT_SYMBOL(blk_mq_put_rq_ref);
static bool blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
struct request *rq, void *priv, bool reserved)
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 13ba1861e688..03e02990609d 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -637,4 +637,7 @@ blk_qc_t blk_mq_submit_bio(struct bio *bio);
void blk_mq_hctx_set_fq_lock_class(struct blk_mq_hw_ctx *hctx,
struct lock_class_key *key);
+void blk_mq_put_rq_ref(struct request *rq);
+struct request *blk_mq_find_and_get_req(struct blk_mq_tags *tags,
+ unsigned int bitnr);
#endif
--
2.31.1
next prev parent reply other threads:[~2021-09-09 14:03 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-09 14:12 [PATCH v5 0/6] handle unexpected message from server Yu Kuai
2021-09-09 14:12 ` [PATCH v5 1/6] nbd: don't handle response without a corresponding request message Yu Kuai
2021-09-14 0:54 ` Ming Lei
2021-09-09 14:12 ` [PATCH v5 2/6] nbd: make sure request completion won't concurrent Yu Kuai
2021-09-14 0:57 ` Ming Lei
2021-09-14 3:11 ` yukuai (C)
2021-09-09 14:12 ` [PATCH v5 3/6] nbd: check sock index in nbd_read_stat() Yu Kuai
2021-09-09 14:12 ` Yu Kuai [this message]
2021-09-09 14:12 ` [PATCH v5 5/6] nbd: convert to use blk_mq_find_and_get_req() Yu Kuai
2021-09-14 1:11 ` Ming Lei
2021-09-14 3:11 ` yukuai (C)
2021-09-14 6:44 ` Ming Lei
2021-09-14 7:13 ` yukuai (C)
2021-09-14 7:46 ` Ming Lei
2021-09-14 9:08 ` yukuai (C)
2021-09-14 9:12 ` yukuai (C)
2021-09-14 14:33 ` Ming Lei
2021-09-14 9:19 ` yukuai (C)
2021-09-14 14:37 ` Ming Lei
2021-09-15 1:54 ` yukuai (C)
2021-09-15 3:16 ` Ming Lei
2021-09-15 3:36 ` yukuai (C)
2021-09-15 3:46 ` Ming Lei
2021-09-09 14:12 ` [PATCH v5 6/6] nbd: don't start request if nbd_queue_rq() failed Yu Kuai
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