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    Subject[PATCH 5.18 106/339] nbd: dont clear NBD_CMD_INFLIGHT flag if request is not completed
    Date
    From: Yu Kuai <yukuai3@huawei.com>

    [ Upstream commit 2895f1831e911ca87d4efdf43e35eb72a0c7e66e ]

    Otherwise io will hung because request will only be completed if the
    cmd has the flag 'NBD_CMD_INFLIGHT'.

    Fixes: 07175cb1baf4 ("nbd: make sure request completion won't concurrent")
    Signed-off-by: Yu Kuai <yukuai3@huawei.com>
    Link: https://lore.kernel.org/r/20220521073749.3146892-4-yukuai3@huawei.com
    Signed-off-by: Jens Axboe <axboe@kernel.dk>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/block/nbd.c | 18 ++++++++++++++----
    1 file changed, 14 insertions(+), 4 deletions(-)

    diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
    index 284557041336..ed678037ba6d 100644
    --- a/drivers/block/nbd.c
    +++ b/drivers/block/nbd.c
    @@ -404,13 +404,14 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
    if (!mutex_trylock(&cmd->lock))
    return BLK_EH_RESET_TIMER;

    - if (!__test_and_clear_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
    + if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
    mutex_unlock(&cmd->lock);
    return BLK_EH_DONE;
    }

    if (!refcount_inc_not_zero(&nbd->config_refs)) {
    cmd->status = BLK_STS_TIMEOUT;
    + __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
    mutex_unlock(&cmd->lock);
    goto done;
    }
    @@ -479,6 +480,7 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
    dev_err_ratelimited(nbd_to_dev(nbd), "Connection timed out\n");
    set_bit(NBD_RT_TIMEDOUT, &config->runtime_flags);
    cmd->status = BLK_STS_IOERR;
    + __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags);
    mutex_unlock(&cmd->lock);
    sock_shutdown(nbd);
    nbd_config_put(nbd);
    @@ -746,7 +748,7 @@ static struct nbd_cmd *nbd_handle_reply(struct nbd_device *nbd, int index,
    cmd = blk_mq_rq_to_pdu(req);

    mutex_lock(&cmd->lock);
    - if (!__test_and_clear_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
    + if (!test_bit(NBD_CMD_INFLIGHT, &cmd->flags)) {
    dev_err(disk_to_dev(nbd->disk), "Suspicious reply %d (status %u flags %lu)",
    tag, cmd->status, cmd->flags);
    ret = -ENOENT;
    @@ -855,8 +857,16 @@ static void recv_work(struct work_struct *work)
    }

    rq = blk_mq_rq_from_pdu(cmd);
    - if (likely(!blk_should_fake_timeout(rq->q)))
    - blk_mq_complete_request(rq);
    + if (likely(!blk_should_fake_timeout(rq->q))) {
    + bool complete;
    +
    + mutex_lock(&cmd->lock);
    + complete = __test_and_clear_bit(NBD_CMD_INFLIGHT,
    + &cmd->flags);
    + mutex_unlock(&cmd->lock);
    + if (complete)
    + blk_mq_complete_request(rq);
    + }
    percpu_ref_put(&q->q_usage_counter);
    }

    --
    2.35.1


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