Hi Nick,
On 5/2/17 10:43 PM, Nicholas A. Bellinger wrote:
On Tue, 2017-05-02 at 13:54 -0500, Bryant G. Ly wrote:
The driver is sending a response to the actual scsi op that was
aborted by an abort task TM, while LIO is sending a response to
the abort task TM.
ibmvscsis_tgt does not send the response to the client until
release_cmd time. The reason for this was because if we did it
at queue_status time, then the client would be free to reuse the
tag for that command, but we're still using the tag until the
command is released at release_cmd time, so we chose to delay
sending the response until then. That then caused this issue, because
release_cmd is always called, even if queue_status is not.
SCSI spec says that the initiator that sends the abort task
TM NEVER gets a response to the aborted op and with the current
code it will send a response. Thus this fix will remove that response
if the TAS bit is set.
Cc: <stable@xxxxxxxxxxxxxxx> # v4.8+
Signed-off-by: Bryant G. Ly <bryantly@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Tyrel Datwyler <tyreld@xxxxxxxxxxxxxxxxxx>
---
drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 66 ++++++++++++++++++++++----------
1 file changed, 45 insertions(+), 21 deletions(-)
Applied, with a small update to the last sentence of the commit log wrt
to 'if ABORTED && !TAS bit is set'.
Thanks Bryant + Tyrel.
So I have been running tests on this patch extensively and it seems like after running 2 hrs of consecutive aborts it fails again with the same problem of driver sending a response to the actual scsi op.
It looks like when LIO processes the abort and if (!__target_check_io_state(se_cmd, se_sess, 0)) then rsp gets set as TMR_TASK_DOES_NOT_EXIST.
With that response the CMD_T_ABORTED state is not set, so then the ibmvscsis driver still sends that duplicate response.
I think the best solution would be in driver when queue_tm_rsp gets called and when the driver builds the response to check for the TMR_TASK_DOES_NOT_EXIST and set our own flag.
Then we would also check for that flag, so it would be:
if ((cmd->se_cmd.transport_state & CMD_T_ABORTED && !(cmd->se_cmd.transport_state & CMD_T_TAS)) || cmd->flags & CMD_ABORTED) {
This will ensure in the CMD_T_ABORTED w/o CMD_T_TAS scenarios are handled and the ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST case.
-Bryant
