RDMA/rtrs-srv: Refactor the handling of failure case in map_cont_bufs

Let's call unmap_cont_bufs when failure happens, and also only update
mrs_num after everything is settled which means we can remove 'mri'.
Acked-by: Md Haris Iqbal <haris.iqbal@ionos.com>
Signed-off-by: Guoqing Jiang <guoqing.jiang@linux.dev>
Link: https://lore.kernel.org/r/20221117101945.6317-3-guoqing.jiang@linux.devSigned-off-by: Leon Romanovsky <leon@kernel.org>

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

@@ -561,9 +561,11 @@ static int map_cont_bufs(struct rtrs_srv_path *srv_path)
 {
 	struct rtrs_srv_sess *srv = srv_path->srv;
 	struct rtrs_path *ss = &srv_path->s;
-	int i, mri, err, mrs_num;
+	int i, err, mrs_num;
 	unsigned int chunk_bits;
 	int chunks_per_mr = 1;
+	struct ib_mr *mr;
+	struct sg_table *sgt;
 
 	/*
 	 * Here we map queue_depth chunks to MR.  Firstly we have to
@@ -586,16 +588,14 @@ static int map_cont_bufs(struct rtrs_srv_path *srv_path)
 	if (!srv_path->mrs)
 		return -ENOMEM;
 
-	srv_path->mrs_num = mrs_num;
-
-	for (mri = 0; mri < mrs_num; mri++) {
-		struct rtrs_srv_mr *srv_mr = &srv_path->mrs[mri];
-		struct sg_table *sgt = &srv_mr->sgt;
+	for (srv_path->mrs_num = 0; srv_path->mrs_num < mrs_num;
+	     srv_path->mrs_num++) {
+		struct rtrs_srv_mr *srv_mr = &srv_path->mrs[srv_path->mrs_num];
 		struct scatterlist *s;
-		struct ib_mr *mr;
 		int nr, nr_sgt, chunks;
 
-		chunks = chunks_per_mr * mri;
+		sgt = &srv_mr->sgt;
+		chunks = chunks_per_mr * srv_path->mrs_num;
 		if (!always_invalidate)
 			chunks_per_mr = min_t(int, chunks_per_mr,
 					      srv->queue_depth - chunks);
@@ -644,14 +644,13 @@ static int map_cont_bufs(struct rtrs_srv_path *srv_path)
 
 		ib_update_fast_reg_key(mr, ib_inc_rkey(mr->rkey));
 		srv_mr->mr = mr;
+	}
+
+	chunk_bits = ilog2(srv->queue_depth - 1) + 1;
+	srv_path->mem_bits = (MAX_IMM_PAYL_BITS - chunk_bits);
+
+	return 0;
 
-		continue;
-err:
-		while (mri--) {
-			srv_mr = &srv_path->mrs[mri];
-			sgt = &srv_mr->sgt;
-			mr = srv_mr->mr;
-			rtrs_iu_free(srv_mr->iu, srv_path->s.dev->ib_dev, 1);
 dereg_mr:
 	ib_dereg_mr(mr);
 unmap_sg:
@@ -659,16 +658,10 @@ static int map_cont_bufs(struct rtrs_srv_path *srv_path)
 			sgt->nents, DMA_BIDIRECTIONAL);
 free_sg:
 	sg_free_table(sgt);
-		}
-		kfree(srv_path->mrs);
+err:
+	unmap_cont_bufs(srv_path);
 
 	return err;
-	}
-
-	chunk_bits = ilog2(srv->queue_depth - 1) + 1;
-	srv_path->mem_bits = (MAX_IMM_PAYL_BITS - chunk_bits);
-
-	return 0;
 }
 
 static void rtrs_srv_hb_err_handler(struct rtrs_con *c)