nbd: protect cmd->status with cmd->lock (de6346ec) · Commits · 戴 / test

We already do this for the most part, except in timeout and clear_req. For the timeout case we take the lock after we grab a ref on the config, but that isn't really necessary because we're safe to touch the cmd at this point, so just move the order around. For the clear_req cause this is initiated by the user, so again is safe. Reviewed-by:

Mike Christie <mchristi@redhat.com> Signed-off-by:

Josef Bacik <josef@toxicpanda.com> Signed-off-by:

Jens Axboe <axboe@kernel.dk>

drivers/block/nbd.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -385,17 +385,16 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
		struct nbd_device *nbd = cmd->nbd;
		struct nbd_config *config;

		if (!mutex_trylock(&cmd->lock))
		return BLK_EH_RESET_TIMER;

		if (!refcount_inc_not_zero(&nbd->config_refs)) {
		cmd->status = BLK_STS_TIMEOUT;
		mutex_unlock(&cmd->lock);
		goto done;
		}
		config = nbd->config;

		if (!mutex_trylock(&cmd->lock)) {
		nbd_config_put(nbd);
		return BLK_EH_RESET_TIMER;
		}

		if (config->num_connections > 1) {
		dev_err_ratelimited(nbd_to_dev(nbd),
		"Connection timed out, retrying (%d/%d alive)\n",
		@@ -792,7 +791,10 @@ static bool nbd_clear_req(struct request req, void data, bool reserved)
		{
		struct nbd_cmd *cmd = blk_mq_rq_to_pdu(req);

		mutex_lock(&cmd->lock);
		cmd->status = BLK_STS_IOERR;
		mutex_unlock(&cmd->lock);

		blk_mq_complete_request(req);
		return true;
		}

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