1 files changed, 22 insertions, 19 deletions

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 9d4ec9273bf9..22a79a62cc4e 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -222,7 +222,7 @@ static ssize_t pid_show(struct device *dev,
 			struct device_attribute *attr, char *buf)
 {
 	struct gendisk *disk = dev_to_disk(dev);
-	struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
+	struct nbd_device *nbd = disk->private_data;
 
 	return sprintf(buf, "%d\n", nbd->pid);
 }
@@ -236,7 +236,7 @@ static ssize_t backend_show(struct device *dev,
 		struct device_attribute *attr, char *buf)
 {
 	struct gendisk *disk = dev_to_disk(dev);
-	struct nbd_device *nbd = (struct nbd_device *)disk->private_data;
+	struct nbd_device *nbd = disk->private_data;
 
 	return sprintf(buf, "%s\n", nbd->backend ?: "");
 }
@@ -588,7 +588,10 @@ static inline int was_interrupted(int result)
 	return result == -ERESTARTSYS || result == -EINTR;
 }
 
-/* always call with the tx_lock held */
+/*
+ * Returns BLK_STS_RESOURCE if the caller should retry after a delay. Returns
+ * -EAGAIN if the caller should requeue @cmd. Returns -EIO if sending failed.
+ */
 static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
 {
 	struct request *req = blk_mq_rq_from_pdu(cmd);
@@ -598,13 +601,15 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
 	struct nbd_request request = {.magic = htonl(NBD_REQUEST_MAGIC)};
 	struct kvec iov = {.iov_base = &request, .iov_len = sizeof(request)};
 	struct iov_iter from;
-	unsigned long size = blk_rq_bytes(req);
 	struct bio *bio;
 	u64 handle;
 	u32 type;
 	u32 nbd_cmd_flags = 0;
 	int sent = nsock->sent, skip = 0;
 
+	lockdep_assert_held(&cmd->lock);
+	lockdep_assert_held(&nsock->tx_lock);
+
 	iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
 
 	type = req_to_nbd_cmd_type(req);
@@ -644,7 +649,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
 	request.type = htonl(type | nbd_cmd_flags);
 	if (type != NBD_CMD_FLUSH) {
 		request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
-		request.len = htonl(size);
+		request.len = htonl(blk_rq_bytes(req));
 	}
 	handle = nbd_cmd_handle(cmd);
 	request.cookie = cpu_to_be64(handle);
@@ -669,7 +674,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
 				nsock->sent = sent;
 			}
 			set_bit(NBD_CMD_REQUEUED, &cmd->flags);
-			return BLK_STS_RESOURCE;
+			return (__force int)BLK_STS_RESOURCE;
 		}
 		dev_err_ratelimited(disk_to_dev(nbd->disk),
 			"Send control failed (result %d)\n", result);
@@ -710,7 +715,7 @@ send_pages:
 					nsock->pending = req;
 					nsock->sent = sent;
 					set_bit(NBD_CMD_REQUEUED, &cmd->flags);
-					return BLK_STS_RESOURCE;
+					return (__force int)BLK_STS_RESOURCE;
 				}
 				dev_err(disk_to_dev(nbd->disk),
 					"Send data failed (result %d)\n",
@@ -1007,7 +1012,7 @@ static int wait_for_reconnect(struct nbd_device *nbd)
 	return !test_bit(NBD_RT_DISCONNECTED, &config->runtime_flags);
 }
 
-static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
+static blk_status_t nbd_handle_cmd(struct nbd_cmd *cmd, int index)
 {
 	struct request *req = blk_mq_rq_from_pdu(cmd);
 	struct nbd_device *nbd = cmd->nbd;
@@ -1015,18 +1020,20 @@ static int nbd_handle_cmd(struct nbd_cmd *cmd, int index)
 	struct nbd_sock *nsock;
 	int ret;
 
+	lockdep_assert_held(&cmd->lock);
+
 	config = nbd_get_config_unlocked(nbd);
 	if (!config) {
 		dev_err_ratelimited(disk_to_dev(nbd->disk),
 				    "Socks array is empty\n");
-		return -EINVAL;
+		return BLK_STS_IOERR;
 	}
 
 	if (index >= config->num_connections) {
 		dev_err_ratelimited(disk_to_dev(nbd->disk),
 				    "Attempted send on invalid socket\n");
 		nbd_config_put(nbd);
-		return -EINVAL;
+		return BLK_STS_IOERR;
 	}
 	cmd->status = BLK_STS_OK;
 again:
@@ -1049,7 +1056,7 @@ again:
 			 */
 			sock_shutdown(nbd);
 			nbd_config_put(nbd);
-			return -EIO;
+			return BLK_STS_IOERR;
 		}
 		goto again;
 	}
@@ -1062,7 +1069,7 @@ again:
 	blk_mq_start_request(req);
 	if (unlikely(nsock->pending && nsock->pending != req)) {
 		nbd_requeue_cmd(cmd);
-		ret = 0;
+		ret = BLK_STS_OK;
 		goto out;
 	}
 	/*
@@ -1081,19 +1088,19 @@ again:
 				    "Request send failed, requeueing\n");
 		nbd_mark_nsock_dead(nbd, nsock, 1);
 		nbd_requeue_cmd(cmd);
-		ret = 0;
+		ret = BLK_STS_OK;
 	}
 out:
 	mutex_unlock(&nsock->tx_lock);
 	nbd_config_put(nbd);
-	return ret;
+	return ret < 0 ? BLK_STS_IOERR : (__force blk_status_t)ret;
 }
 
 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 			const struct blk_mq_queue_data *bd)
 {
 	struct nbd_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
-	int ret;
+	blk_status_t ret;
 
 	/*
 	 * Since we look at the bio's to send the request over the network we
@@ -1113,10 +1120,6 @@ static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,
 	 * appropriate.
 	 */
 	ret = nbd_handle_cmd(cmd, hctx->queue_num);
-	if (ret < 0)
-		ret = BLK_STS_IOERR;
-	else if (!ret)
-		ret = BLK_STS_OK;
 	mutex_unlock(&cmd->lock);
 
 	return ret;