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Commit 40b05497 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

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: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 2ff017f5

drivers/target/iscsi/iscsi_target_util.c

+15 −7
Original line number Diff line number Diff line
@@ -1256,7 +1256,7 @@ int iscsit_fe_sendpage_sg( 
	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 @@ send_hdr: 
	}



	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_pg: 


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_padding: 


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) {