[PATCH] nvmet-tcp: fix data digest calculation for multiple H2CData PDUs

[Varun Prakash <varun@chelsio.com>]

On receiving H2CData PDU current code calculates data digest for the entire
transfer length, it works if host sends only one H2CData PDU per cmd, if
host sends multiple H2CData PDU per cmd then target reports data digest
error.

This issue was fixed in commit fda871c0ba5d ("nvmet-tcp: fix receive data
digest calculation for multiple h2cdata PDUs").

commit ed0691cf5514 ("nvmet-tcp: fix regression in data_digest
calculation") reverted the fix done in the above commit.

Fixes: ed0691cf5514 ("nvmet-tcp: fix regression in data_digest calculation")
Signed-off-by: Rakshana Sridhar <rakshanas@chelsio.com>
Signed-off-by: Varun Prakash <varun@chelsio.com>
---
 drivers/nvme/target/tcp.c | 31 +++++++++++++++++++++++++++----
 1 file changed, 27 insertions(+), 4 deletions(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 05163751f2e5..e5e3498675af 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -415,8 +415,8 @@ static int nvmet_tcp_map_data(struct nvmet_tcp_cmd *cmd)
 	return NVME_SC_INTERNAL;
 }
 
-static void nvmet_tcp_calc_ddgst(struct ahash_request *hash,
-		struct nvmet_tcp_cmd *cmd)
+static void nvmet_tcp_send_ddgst(struct ahash_request *hash,
+				 struct nvmet_tcp_cmd *cmd)
 {
 	ahash_request_set_crypt(hash, cmd->req.sg,
 		(void *)&cmd->exp_ddgst, cmd->req.transfer_len);
@@ -447,7 +447,7 @@ static void nvmet_setup_c2h_data_pdu(struct nvmet_tcp_cmd *cmd)
 
 	if (queue->data_digest) {
 		pdu->hdr.flags |= NVME_TCP_F_DDGST;
-		nvmet_tcp_calc_ddgst(queue->snd_hash, cmd);
+		nvmet_tcp_send_ddgst(queue->snd_hash, cmd);
 	}
 
 	if (cmd->queue->hdr_digest) {
@@ -1152,11 +1152,34 @@ static int nvmet_tcp_try_recv_pdu(struct nvmet_tcp_queue *queue)
 	return nvmet_tcp_done_recv_pdu(queue);
 }
 
+static void nvmet_tcp_recv_ddgst(struct ahash_request *hash,
+				 struct nvmet_tcp_cmd *cmd)
+{
+	struct bio_vec *iov = cmd->iov;
+	struct scatterlist sg;
+	u32 data_length = cmd->pdu_len;
+
+	sg_init_table(&sg, 1);
+	crypto_ahash_init(hash);
+
+	while (data_length) {
+		sg_set_page(&sg, iov->bv_page, iov->bv_len, iov->bv_offset);
+		ahash_request_set_crypt(hash, &sg, NULL, iov->bv_len);
+		crypto_ahash_update(hash);
+
+		data_length -= iov->bv_len;
+		iov++;
+	}
+
+	ahash_request_set_crypt(hash, NULL, (void *)&cmd->exp_ddgst, 0);
+	crypto_ahash_final(hash);
+}
+
 static void nvmet_tcp_prep_recv_ddgst(struct nvmet_tcp_cmd *cmd)
 {
 	struct nvmet_tcp_queue *queue = cmd->queue;
 
-	nvmet_tcp_calc_ddgst(queue->rcv_hash, cmd);
+	nvmet_tcp_recv_ddgst(queue->rcv_hash, cmd);
 	queue->offset = 0;
 	queue->left = NVME_TCP_DIGEST_LENGTH;
 	queue->rcv_state = NVMET_TCP_RECV_DDGST;
-- 
2.31.1