[PATCH 1/3] target: Fix compare_and_write_callback handling for non GOOD status

From: Nicholas A. Bellinger
Date: Wed May 03 2017 - 02:12:24 EST

From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>

Following the bugfix for handling non SAM_STAT_GOOD COMPARE_AND_WRITE
status during COMMIT phase in commit 9b2792c3da1, the same bug exists
for the READ phase as well.

This would manifest first as a lost SCSI response, and eventual
hung task during fabric driver logout or re-login, as existing
shutdown logic waited for the COMPARE_AND_WRITE se_cmd->cmd_kref
to reach zero.

To address this bug, compare_and_write_callback() has been changed
to set post_ret = 1 and return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE
as necessary to signal failure status.

Reported-by: Bill Borsari <wgb@xxxxxxxxx>
Cc: Bill Borsari <wgb@xxxxxxxxx>
Tested-by: Gary Guo <ghg@xxxxxxxxx>
Cc: Gary Guo <ghg@xxxxxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
drivers/target/target_core_sbc.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
index f9250b3..a0ad618 100644
--- a/drivers/target/target_core_sbc.c
+++ b/drivers/target/target_core_sbc.c
@@ -507,8 +507,11 @@ static sense_reason_t compare_and_write_callback(struct se_cmd *cmd, bool succes
* been failed with a non-zero SCSI status.
if (cmd->scsi_status) {
- pr_err("compare_and_write_callback: non zero scsi_status:"
+ pr_debug("compare_and_write_callback: non zero scsi_status:"
" 0x%02x\n", cmd->scsi_status);
+ *post_ret = 1;
+ if (cmd->scsi_status == SAM_STAT_CHECK_CONDITION)
goto out;