nbd: Remove __force casts

Make it again possible for sparse to verify that blk_status_t and Unix
error codes are used in the proper context by making nbd_send_cmd()
return a blk_status_t instead of an integer.

No functionality has been changed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
[ bvanassche: added description and made two small formatting changes ]
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20240604221531.327131-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 22a79a62cc4eab9748235bca800e93aa06f068fd..b87aa80a46ddaac812230f7149cbceda2b437ede 100644 (file)
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -589,10 +589,11 @@ static inline int was_interrupted(int result)
 }
 
 /*
- * 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.
+ * Returns BLK_STS_RESOURCE if the caller should retry after a delay.
+ * Returns BLK_STS_IOERR if sending failed.
  */
-static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
+static blk_status_t nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd,
+                                int index)
 {
        struct request *req = blk_mq_rq_from_pdu(cmd);
        struct nbd_config *config = nbd->config;
@@ -614,13 +615,13 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
 
        type = req_to_nbd_cmd_type(req);
        if (type == U32_MAX)
-               return -EIO;
+               return BLK_STS_IOERR;
 
        if (rq_data_dir(req) == WRITE &&
            (config->flags & NBD_FLAG_READ_ONLY)) {
                dev_err_ratelimited(disk_to_dev(nbd->disk),
                                    "Write on read-only\n");
-               return -EIO;
+               return BLK_STS_IOERR;
        }
 
        if (req->cmd_flags & REQ_FUA)
@@ -674,11 +675,11 @@ 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 (__force int)BLK_STS_RESOURCE;
+                       return BLK_STS_RESOURCE;
                }
                dev_err_ratelimited(disk_to_dev(nbd->disk),
                        "Send control failed (result %d)\n", result);
-               return -EAGAIN;
+               goto requeue;
        }
 send_pages:
        if (type != NBD_CMD_WRITE)
@@ -715,12 +716,12 @@ send_pages:
                                        nsock->pending = req;
                                        nsock->sent = sent;
                                        set_bit(NBD_CMD_REQUEUED, &cmd->flags);
-                                       return (__force int)BLK_STS_RESOURCE;
+                                       return BLK_STS_RESOURCE;
                                }
                                dev_err(disk_to_dev(nbd->disk),
                                        "Send data failed (result %d)\n",
                                        result);
-                               return -EAGAIN;
+                               goto requeue;
                        }
                        /*
                         * The completion might already have come in,
@@ -737,7 +738,16 @@ out:
        trace_nbd_payload_sent(req, handle);
        nsock->pending = NULL;
        nsock->sent = 0;
-       return 0;
+       __set_bit(NBD_CMD_INFLIGHT, &cmd->flags);
+       return BLK_STS_OK;
+
+requeue:
+       /* retry on a different socket */
+       dev_err_ratelimited(disk_to_dev(nbd->disk),
+                           "Request send failed, requeueing\n");
+       nbd_mark_nsock_dead(nbd, nsock, 1);
+       nbd_requeue_cmd(cmd);
+       return BLK_STS_OK;
 }
 
 static int nbd_read_reply(struct nbd_device *nbd, struct socket *sock,
@@ -1018,7 +1028,7 @@ static blk_status_t nbd_handle_cmd(struct nbd_cmd *cmd, int index)
        struct nbd_device *nbd = cmd->nbd;
        struct nbd_config *config;
        struct nbd_sock *nsock;
-       int ret;
+       blk_status_t ret;
 
        lockdep_assert_held(&cmd->lock);
 
@@ -1072,28 +1082,11 @@ again:
                ret = BLK_STS_OK;
                goto out;
        }
-       /*
-        * Some failures are related to the link going down, so anything that
-        * returns EAGAIN can be retried on a different socket.
-        */
        ret = nbd_send_cmd(nbd, cmd, index);
-       /*
-        * Access to this flag is protected by cmd->lock, thus it's safe to set
-        * the flag after nbd_send_cmd() succeed to send request to server.
-        */
-       if (!ret)
-               __set_bit(NBD_CMD_INFLIGHT, &cmd->flags);
-       else if (ret == -EAGAIN) {
-               dev_err_ratelimited(disk_to_dev(nbd->disk),
-                                   "Request send failed, requeueing\n");
-               nbd_mark_nsock_dead(nbd, nsock, 1);
-               nbd_requeue_cmd(cmd);
-               ret = BLK_STS_OK;
-       }
 out:
        mutex_unlock(&nsock->tx_lock);
        nbd_config_put(nbd);
-       return ret < 0 ? BLK_STS_IOERR : (__force blk_status_t)ret;
+       return ret;
 }
 
 static blk_status_t nbd_queue_rq(struct blk_mq_hw_ctx *hctx,