[PATCH 5.4 64/92] nvmet-tcp: fix incomplete data digest send

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Varun Prakash <varun@chelsio.com>

[ Upstream commit 102110efdff6beedece6ab9b51664c32ac01e2db ]

Current nvmet_try_send_ddgst() code does not check whether
all data digest bytes are transmitted, fix this by returning
-EAGAIN if all data digest bytes are not transmitted.

Fixes: 872d26a391da ("nvmet-tcp: add NVMe over TCP target driver")
Signed-off-by: Varun Prakash <varun@chelsio.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/target/tcp.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index fac1985870765..4341c72446628 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -631,10 +631,11 @@ static int nvmet_try_send_r2t(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
 static int nvmet_try_send_ddgst(struct nvmet_tcp_cmd *cmd)
 {
 	struct nvmet_tcp_queue *queue = cmd->queue;
+	int left = NVME_TCP_DIGEST_LENGTH - cmd->offset;
 	struct msghdr msg = { .msg_flags = MSG_DONTWAIT };
 	struct kvec iov = {
 		.iov_base = (u8 *)&cmd->exp_ddgst + cmd->offset,
-		.iov_len = NVME_TCP_DIGEST_LENGTH - cmd->offset
+		.iov_len = left
 	};
 	int ret;
 
@@ -643,6 +644,10 @@ static int nvmet_try_send_ddgst(struct nvmet_tcp_cmd *cmd)
 		return ret;
 
 	cmd->offset += ret;
+	left -= ret;
+
+	if (left)
+		return -EAGAIN;
 
 	if (queue->nvme_sq.sqhd_disabled) {
 		cmd->queue->snd_cmd = NULL;
-- 
2.33.0