iscsi-target: Fix sendpage breakage with proper padding+DataDigest iovec offsets
This patch fixes a bug in the iscsit_fe_sendpage_sg() transmit codepath that
was originally introduced with the v3.1 iscsi-target merge that incorrectly
uses hardcoded cmd->iov_data_count values to determine cmd->iov_data[] offsets
for extra outgoing padding and DataDigest payload vectors.
This code is obviously incorrect for the DataDigest enabled case with sendpage
offload, and this fix ensures correct operation for padding + DataDigest,
padding only, and DataDigest only cases. The bug was introduced during a
pre-merge change in iscsit_fe_sendpage_sg() to natively use struct scatterlist
instead of the legacy v3.0 struct se_mem logic.
Cc: Andy Grover <agrover@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 1d1b4fe..f00137f 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -1256,7 +1256,7 @@
struct kvec iov;
u32 tx_hdr_size, data_len;
u32 offset = cmd->first_data_sg_off;
- int tx_sent;
+ int tx_sent, iov_off;
send_hdr:
tx_hdr_size = ISCSI_HDR_LEN;
@@ -1276,9 +1276,19 @@
}
data_len = cmd->tx_size - tx_hdr_size - cmd->padding;
- if (conn->conn_ops->DataDigest)
+ /*
+ * Set iov_off used by padding and data digest tx_data() calls below
+ * in order to determine proper offset into cmd->iov_data[]
+ */
+ if (conn->conn_ops->DataDigest) {
data_len -= ISCSI_CRC_LEN;
-
+ if (cmd->padding)
+ iov_off = (cmd->iov_data_count - 2);
+ else
+ iov_off = (cmd->iov_data_count - 1);
+ } else {
+ iov_off = (cmd->iov_data_count - 1);
+ }
/*
* Perform sendpage() for each page in the scatterlist
*/
@@ -1307,8 +1317,7 @@
send_padding:
if (cmd->padding) {
- struct kvec *iov_p =
- &cmd->iov_data[cmd->iov_data_count-1];
+ struct kvec *iov_p = &cmd->iov_data[iov_off++];
tx_sent = tx_data(conn, iov_p, 1, cmd->padding);
if (cmd->padding != tx_sent) {
@@ -1322,8 +1331,7 @@
send_datacrc:
if (conn->conn_ops->DataDigest) {
- struct kvec *iov_d =
- &cmd->iov_data[cmd->iov_data_count];
+ struct kvec *iov_d = &cmd->iov_data[iov_off];
tx_sent = tx_data(conn, iov_d, 1, ISCSI_CRC_LEN);
if (ISCSI_CRC_LEN != tx_sent) {