xprtrdma: Remove rpcrdma_buffer::rb_mrlock

Clean up: Now that the free list is used sparingly, get rid of the
separate spin lock protecting it.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

net/sunrpc/xprtrdma/frwr_ops.c

@@ -106,10 +106,10 @@ frwr_mr_recycle_worker(struct work_struct *work)
 		mr->mr_dir = DMA_NONE;
 	}
 
-	spin_lock(&r_xprt->rx_buf.rb_mrlock);
+	spin_lock(&r_xprt->rx_buf.rb_lock);
 	list_del(&mr->mr_all);
 	r_xprt->rx_stats.mrs_recycled++;
-	spin_unlock(&r_xprt->rx_buf.rb_mrlock);
+	spin_unlock(&r_xprt->rx_buf.rb_lock);
 
 	frwr_release_mr(mr);
 }

net/sunrpc/xprtrdma/verbs.c

@@ -962,10 +962,10 @@ rpcrdma_mrs_create(struct rpcrdma_xprt *r_xprt)
 
 		mr->mr_xprt = r_xprt;
 
-		spin_lock(&buf->rb_mrlock);
+		spin_lock(&buf->rb_lock);
 		list_add(&mr->mr_list, &buf->rb_mrs);
 		list_add(&mr->mr_all, &buf->rb_all_mrs);
-		spin_unlock(&buf->rb_mrlock);
+		spin_unlock(&buf->rb_lock);
 	}
 
 	r_xprt->rx_stats.mrs_allocated += count;
@@ -1084,7 +1084,6 @@ int rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
 
 	buf->rb_max_requests = r_xprt->rx_ep.rep_max_requests;
 	buf->rb_bc_srv_max_requests = 0;
-	spin_lock_init(&buf->rb_mrlock);
 	spin_lock_init(&buf->rb_lock);
 	INIT_LIST_HEAD(&buf->rb_mrs);
 	INIT_LIST_HEAD(&buf->rb_all_mrs);
@@ -1154,18 +1153,18 @@ rpcrdma_mrs_destroy(struct rpcrdma_buffer *buf)
 	unsigned int count;
 
 	count = 0;
-	spin_lock(&buf->rb_mrlock);
+	spin_lock(&buf->rb_lock);
 	while ((mr = list_first_entry_or_null(&buf->rb_all_mrs,
 					      struct rpcrdma_mr,
 					      mr_all)) != NULL) {
 		list_del(&mr->mr_all);
-		spin_unlock(&buf->rb_mrlock);
+		spin_unlock(&buf->rb_lock);
 
 		frwr_release_mr(mr);
 		count++;
-		spin_lock(&buf->rb_mrlock);
+		spin_lock(&buf->rb_lock);
 	}
-	spin_unlock(&buf->rb_mrlock);
+	spin_unlock(&buf->rb_lock);
 	r_xprt->rx_stats.mrs_allocated = 0;
 }
 
@@ -1218,9 +1217,9 @@ rpcrdma_mr_get(struct rpcrdma_xprt *r_xprt)
 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 	struct rpcrdma_mr *mr;
 
-	spin_lock(&buf->rb_mrlock);
+	spin_lock(&buf->rb_lock);
 	mr = rpcrdma_mr_pop(&buf->rb_mrs);
-	spin_unlock(&buf->rb_mrlock);
+	spin_unlock(&buf->rb_lock);
 	return mr;
 }
 
@@ -1249,9 +1248,9 @@ static void rpcrdma_mr_free(struct rpcrdma_mr *mr)
 	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
 
 	mr->mr_req = NULL;
-	spin_lock(&buf->rb_mrlock);
+	spin_lock(&buf->rb_lock);
 	rpcrdma_mr_push(mr, &buf->rb_mrs);
-	spin_unlock(&buf->rb_mrlock);
+	spin_unlock(&buf->rb_lock);
 }
 
 /**

net/sunrpc/xprtrdma/xprt_rdma.h

@@ -360,19 +360,18 @@ rpcrdma_mr_pop(struct list_head *list)
  * One of these is associated with a transport instance
  */
 struct rpcrdma_buffer {
-	spinlock_t		rb_mrlock;	/* protect rb_mrs list */
+	spinlock_t		rb_lock;
+	struct list_head	rb_send_bufs;
+	struct list_head	rb_recv_bufs;
 	struct list_head	rb_mrs;
-	struct list_head	rb_all_mrs;
 
 	unsigned long		rb_sc_head;
 	unsigned long		rb_sc_tail;
 	unsigned long		rb_sc_last;
 	struct rpcrdma_sendctx	**rb_sc_ctxs;
 
-	spinlock_t		rb_lock;	/* protect buf lists */
-	struct list_head	rb_send_bufs;
-	struct list_head	rb_recv_bufs;
 	struct list_head	rb_allreqs;
+	struct list_head	rb_all_mrs;
 
 	u32			rb_max_requests;
 	u32			rb_credits;	/* most recent credit grant */