From 40b054970afcf067896d62cd6f7e617c62665304 Mon Sep 17 00:00:00 2001 From: Nicholas Bellinger Date: Fri, 16 Sep 2011 16:55:47 -0700 Subject: [PATCH] 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 Cc: Christoph Hellwig Signed-off-by: Nicholas Bellinger --- drivers/target/iscsi/iscsi_target_util.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) 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 @@ 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) { -- 2.7.4