[35/88] tcm_qla2xxx: Fix residual for underrun commands that fail

Steven Rostedt
2013-08-13T16:03:30Z

[-- Attachment #1: 0035-tcm_qla2xxx-Fix-residual-for-underrun-commands-that-.patch --]
[-- Type: text/plain, Size: 2063 bytes --]

3.6.11.7-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Roland Dreier <roland@purestorage.com>

[ Upstream commit b5aff3d2747bea08b386edd070941a45611ffe51 ]

Suppose an initiator sends a DATA IN command with an allocation length
shorter than the FC transfer length -- we get a target message like

TARGET_CORE[qla2xxx]: Expected Transfer Length: 256 does not match SCSI CDB Length: 0 for SAM Opcode: 0x12

In that case, the target core adjusts the data_length and sets
se_cmd->residual_count for the underrun. But now suppose that command
fails and we end up in tcm_qla2xxx_queue_status() -- that function
unconditionally overwrites residual_count with the already adjusted
data_length, and the initiator will burp with a message like

qla2xxx [0000:00:06.0]-301d:0: Dropped frame(s) detected (0x100 of 0x100 bytes).

Fix this by adding on to the existing underflow residual count instead.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: Giridhar Malavali <giridhar.malavali@qlogic.com>
Cc: Chad Dupuis <chad.dupuis@qlogic.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
drivers/scsi/qla2xxx/tcm_qla2xxx.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/qla2xxx/tcm_qla2xxx.c b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
index 7fa0672..bda062d 100644
--- a/drivers/scsi/qla2xxx/tcm_qla2xxx.c
+++ b/drivers/scsi/qla2xxx/tcm_qla2xxx.c
@@ -688,8 +688,12 @@ static int tcm_qla2xxx_queue_status(struct se_cmd *se_cmd)
* For FCP_READ with CHECK_CONDITION status, clear cmd->bufflen
* for qla_tgt_xmit_response LLD code
*/
+ if (se_cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
+ se_cmd->se_cmd_flags &= ~SCF_OVERFLOW_BIT;
+ se_cmd->residual_count = 0;
+ }
se_cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
- se_cmd->residual_count = se_cmd->data_length;
+ se_cmd->residual_count += se_cmd->data_length;

cmd->bufflen = 0;
}
--
1.7.10.4