[patch v8 5/7] nbd: clean up return value checking of sock_xmit()

Yu Kuai
2021-09-16T09:24:14Z

Check if sock_xmit() return 0 is useless because it'll never return
0, comment it and remove such checkings.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
---
drivers/block/nbd.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 22c91d8901f6..7f9e030e41ce 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -490,7 +490,8 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
}

/*
- * Send or receive packet.
+ * Send or receive packet. Return a positive value on success and
+ * negtive value on failue, and never return 0.
*/
static int sock_xmit(struct nbd_device *nbd, int index, int send,
struct iov_iter *iter, int msg_flags, int *sent)
@@ -616,7 +617,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
result = sock_xmit(nbd, index, 1, &from,
(type == NBD_CMD_WRITE) ? MSG_MORE : 0, &sent);
trace_nbd_header_sent(req, handle);
- if (result <= 0) {
+ if (result < 0) {
if (was_interrupted(result)) {
/* If we havne't sent anything we can just return BUSY,
* however if we have sent something we need to make
@@ -660,7 +661,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
skip = 0;
}
result = sock_xmit(nbd, index, 1, &from, flags, &sent);
- if (result <= 0) {
+ if (result < 0) {
if (was_interrupted(result)) {
/* We've already sent the header, we
* have no choice but to set pending and
@@ -712,7 +713,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
reply.magic = 0;
iov_iter_kvec(&to, READ, &iov, 1, sizeof(reply));
result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
- if (result <= 0) {
+ if (result < 0) {
if (!nbd_disconnected(config))
dev_err(disk_to_dev(nbd->disk),
"Receive control failed (result %d)\n", result);
@@ -783,7 +784,7 @@ static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
rq_for_each_segment(bvec, req, iter) {
iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);
result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
- if (result <= 0) {
+ if (result < 0) {
dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
result);
/*
@@ -1229,7 +1230,7 @@ static void send_disconnects(struct nbd_device *nbd)
iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
mutex_lock(&nsock->tx_lock);
ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
- if (ret <= 0)
+ if (ret < 0)
dev_err(disk_to_dev(nbd->disk),
"Send disconnect failed %d\n", ret);
mutex_unlock(&nsock->tx_lock);
--
2.31.1