RDMA/rtrs-clt: Fix counting inflight IO

There are mis-match at counting inflight IO after changing the multipath
policy.

For example, we started fio test with round-robin policy and then we
changed the policy to min-inflight. IOs created under the RR policy is
finished under the min-inflight policy and inflight counter only
decreased. So the counter would be negative value.  And also we started
fio test with min-inflight policy and changed the policy to the
round-robin. IOs created under the min-inflight policy increased the
inflight IO counter but the inflight IO counter was not decreased because
the policy was the round-robin when IO was finished.

So it should count IOs only if the IO is created under the min-inflight
policy. It should not care the policy when the IO is finished.

This patch adds a field mp_policy in struct rtrs_clt_io_req and stores the
multipath policy when an object of rtrs_clt_io_req is created. Then
rtrs-clt checks the mp_policy of only struct rtrs_clt_io_req instead of
the struct rtrs_clt.

Link: https://lore.kernel.org/r/20210806112112.124313-6-haris.iqbal@ionos.comSigned-off-by: Gioh Kim <gi-oh.kim@ionos.com>
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/ulp/rtrs/rtrs-clt-stats.c

@@ -180,7 +180,7 @@ void rtrs_clt_update_all_stats(struct rtrs_clt_io_req *req, int dir)
 
 	len = req->usr_len + req->data_len;
 	rtrs_clt_update_rdma_stats(stats, len, dir);
-	if (sess->clt->mp_policy == MP_POLICY_MIN_INFLIGHT)
+	if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
 		atomic_inc(&stats->inflight);
 }
 

drivers/infiniband/ulp/rtrs/rtrs-clt.c

@@ -438,7 +438,7 @@ static void complete_rdma_req(struct rtrs_clt_io_req *req, int errno,
 	}
 	if (!refcount_dec_and_test(&req->ref))
 		return;
-	if (sess->clt->mp_policy == MP_POLICY_MIN_INFLIGHT)
+	if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
 		atomic_dec(&sess->stats->inflight);
 
 	req->in_use = false;
@@ -964,6 +964,7 @@ static void rtrs_clt_init_req(struct rtrs_clt_io_req *req,
 	req->need_inv_comp = false;
 	req->inv_errno = 0;
 	refcount_set(&req->ref, 1);
+	req->mp_policy = sess->clt->mp_policy;
 
 	iov_iter_kvec(&iter, READ, vec, 1, usr_len);
 	len = _copy_from_iter(req->iu->buf, usr_len, &iter);
@@ -1154,7 +1155,7 @@ static int rtrs_clt_write_req(struct rtrs_clt_io_req *req)
 			    "Write request failed: error=%d path=%s [%s:%u]\n",
 			    ret, kobject_name(&sess->kobj), sess->hca_name,
 			    sess->hca_port);
-		if (sess->clt->mp_policy == MP_POLICY_MIN_INFLIGHT)
+		if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
 			atomic_dec(&sess->stats->inflight);
 		if (req->sg_cnt)
 			ib_dma_unmap_sg(sess->s.dev->ib_dev, req->sglist,
@@ -1260,7 +1261,7 @@ static int rtrs_clt_read_req(struct rtrs_clt_io_req *req)
 			    "Read request failed: error=%d path=%s [%s:%u]\n",
 			    ret, kobject_name(&sess->kobj), sess->hca_name,
 			    sess->hca_port);
-		if (sess->clt->mp_policy == MP_POLICY_MIN_INFLIGHT)
+		if (req->mp_policy == MP_POLICY_MIN_INFLIGHT)
 			atomic_dec(&sess->stats->inflight);
 		req->need_inv = false;
 		if (req->sg_cnt)

drivers/infiniband/ulp/rtrs/rtrs-clt.h

@@ -101,6 +101,7 @@ struct rtrs_clt_io_req {
 	unsigned int		usr_len;
 	void			*priv;
 	bool			in_use;
+	enum rtrs_mp_policy     mp_policy;
 	struct rtrs_clt_con	*con;
 	struct rtrs_sg_desc	*desc;
 	struct ib_sge		*sge;