[PATCH 4.4 43/46] target/iscsi: Fix unsolicited data seq_end_offset calculation

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Varun Prakash 


[ Upstream commit 4d65491c269729a1e3b375c45e73213f49103d33 ]

In case of unsolicited data for the first sequence
seq_end_offset must be set to minimum of total data length
and FirstBurstLength, so do not add cmd->write_data_done
to the min of total data length and FirstBurstLength.

This patch avoids that with ImmediateData=Yes, InitialR2T=No,
MaxXmitDataSegmentLength < FirstBurstLength that a WRITE command
with IO size above FirstBurstLength triggers sequence error
messages, for example

Set following parameters on target (linux-4.8.12)
ImmediateData = Yes
InitialR2T = No
MaxXmitDataSegmentLength = 8k
FirstBurstLength = 64k

Log in from Open iSCSI initiator and execute
dd if=/dev/zero of=/dev/sdb bs=128k count=1 oflag=direct

Error messages on target
Command ITT: 0x0035 with Offset: 65536, Length: 8192 outside
of Sequence 73728:131072 while DataSequenceInOrder=Yes.
Command ITT: 0x0035, received DataSN: 0x0001 higher than
expected 0x.
Unable to perform within-command recovery while ERL=0.

Signed-off-by: Varun Prakash 
[ bvanassche: Use min() instead of open-coding it / edited patch description ]
Signed-off-by: Bart Van Assche 
Signed-off-by: Nicholas Bellinger 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/target/iscsi/iscsi_target_erl0.c |6 ++
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/target/iscsi/iscsi_target_erl0.c
+++ b/drivers/target/iscsi/iscsi_target_erl0.c
@@ -44,10 +44,8 @@ void iscsit_set_dataout_sequence_values(
 */
if (cmd->unsolicited_data) {
cmd->seq_start_offset = cmd->write_data_done;
-   cmd->seq_end_offset = (cmd->write_data_done +
-   ((cmd->se_cmd.data_length >
- conn->sess->sess_ops->FirstBurstLength) ?
-conn->sess->sess_ops->FirstBurstLength : 
cmd->se_cmd.data_length));
+   cmd->seq_end_offset = min(cmd->se_cmd.data_length,
+   conn->sess->sess_ops->FirstBurstLength);
return;
}
 

[PATCH 4.4 43/46] target/iscsi: Fix unsolicited data seq_end_offset calculation

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Varun Prakash 


[ Upstream commit 4d65491c269729a1e3b375c45e73213f49103d33 ]

In case of unsolicited data for the first sequence
seq_end_offset must be set to minimum of total data length
and FirstBurstLength, so do not add cmd->write_data_done
to the min of total data length and FirstBurstLength.

This patch avoids that with ImmediateData=Yes, InitialR2T=No,
MaxXmitDataSegmentLength < FirstBurstLength that a WRITE command
with IO size above FirstBurstLength triggers sequence error
messages, for example

Set following parameters on target (linux-4.8.12)
ImmediateData = Yes
InitialR2T = No
MaxXmitDataSegmentLength = 8k
FirstBurstLength = 64k

Log in from Open iSCSI initiator and execute
dd if=/dev/zero of=/dev/sdb bs=128k count=1 oflag=direct

Error messages on target
Command ITT: 0x0035 with Offset: 65536, Length: 8192 outside
of Sequence 73728:131072 while DataSequenceInOrder=Yes.
Command ITT: 0x0035, received DataSN: 0x0001 higher than
expected 0x.
Unable to perform within-command recovery while ERL=0.

Signed-off-by: Varun Prakash 
[ bvanassche: Use min() instead of open-coding it / edited patch description ]
Signed-off-by: Bart Van Assche 
Signed-off-by: Nicholas Bellinger 

Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 drivers/target/iscsi/iscsi_target_erl0.c |6 ++
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/target/iscsi/iscsi_target_erl0.c
+++ b/drivers/target/iscsi/iscsi_target_erl0.c
@@ -44,10 +44,8 @@ void iscsit_set_dataout_sequence_values(
 */
if (cmd->unsolicited_data) {
cmd->seq_start_offset = cmd->write_data_done;
-   cmd->seq_end_offset = (cmd->write_data_done +
-   ((cmd->se_cmd.data_length >
- conn->sess->sess_ops->FirstBurstLength) ?
-conn->sess->sess_ops->FirstBurstLength : 
cmd->se_cmd.data_length));
+   cmd->seq_end_offset = min(cmd->se_cmd.data_length,
+   conn->sess->sess_ops->FirstBurstLength);
return;
}