[RFC PATCH] mpt3sas: support target smid for [abort|query] task

[Minwoo Im <minwoo.im@samsung.com>]

We can request task management IOCTL command(MPI2_FUNCTION_SCSI_TASK_MGMT)
to /dev/mpt3ctl.  If the given task_type is either abort task or query
task, it may need a field named "Initiator Port Transfer Tag to Manage"
in the IU.

Current code does not support to check target IPTT tag from the
tm_request.  This patch introduces to check TaskMID given from the
userspace as a target tag.  We have a rule of relationship between
(struct request *req->tag) and smid in mpt3sas_base.c:

3318 u16
3319 mpt3sas_base_get_smid_scsiio(struct MPT3SAS_ADAPTER *ioc, u8 cb_idx,
3320         struct scsi_cmnd *scmd)
3321 {
3322         struct scsiio_tracker *request = scsi_cmd_priv(scmd);
3323         unsigned int tag = scmd->request->tag;
3324         u16 smid;
3325
3326         smid = tag + 1;

So if we want to abort a request tagged #X, then we can pass (X + 1) to
this IOCTL handler.

Signed-off-by: Minwoo Im <minwoo.im@samsung.com>
---
 drivers/scsi/mpt3sas/mpt3sas_ctl.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/mpt3sas/mpt3sas_ctl.c b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
index b2bb47c14d35..5c7539dae713 100644
--- a/drivers/scsi/mpt3sas/mpt3sas_ctl.c
+++ b/drivers/scsi/mpt3sas/mpt3sas_ctl.c
@@ -596,15 +596,17 @@ _ctl_set_task_mid(struct MPT3SAS_ADAPTER *ioc, struct mpt3_ioctl_command *karg,
 		if (priv_data->sas_target->handle != handle)
 			continue;
 		st = scsi_cmd_priv(scmd);
-		tm_request->TaskMID = cpu_to_le16(st->smid);
-		found = 1;
+		if (tm_request->TaskMID == st->smid) {
+			tm_request->TaskMID = cpu_to_le16(st->smid);
+			found = 1;
+		}
 	}
 
 	if (!found) {
 		dctlprintk(ioc,
-			   ioc_info(ioc, "%s: handle(0x%04x), lun(%d), no active mid!!\n",
+			   ioc_info(ioc, "%s: handle(0x%04x), lun(%d), no matched mid(%d)!!\n",
 				    desc, le16_to_cpu(tm_request->DevHandle),
-				    lun));
+				    lun, tm_request->TaskMID));
 		tm_reply = ioc->ctl_cmds.reply;
 		tm_reply->DevHandle = tm_request->DevHandle;
 		tm_reply->Function = MPI2_FUNCTION_SCSI_TASK_MGMT;
-- 
2.16.1