netfs: Use bh-disabling spinlocks for rreq->lock

Use bh-disabling spinlocks when accessing rreq->lock because, in the
future, it may be twiddled from softirq context when cleanup is driven from
cache backend DIO completion.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Jeff Layton <jlayton@kernel.org>
cc: netfs@lists.linux.dev
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20240814203850.2240469-12-dhowells@redhat.com/ # v2
Signed-off-by: Christian Brauner <brauner@kernel.org>

fs/netfs/write_collect.c

@@ -473,7 +473,7 @@ static void netfs_collect_write_results(struct netfs_io_request *wreq)
 
 		cancel:
 			/* Remove if completely consumed. */
-			spin_lock(&wreq->lock);
+			spin_lock_bh(&wreq->lock);
 
 			remove = front;
 			list_del_init(&front->rreq_link);
@@ -489,7 +489,7 @@ static void netfs_collect_write_results(struct netfs_io_request *wreq)
 				}
 			}
 
-			spin_unlock(&wreq->lock);
+			spin_unlock_bh(&wreq->lock);
 			netfs_put_subrequest(remove, false,
 					     notes & SAW_FAILURE ?
 					     netfs_sreq_trace_put_cancel :

fs/netfs/write_issue.c

@@ -191,7 +191,7 @@ static void netfs_prepare_write(struct netfs_io_request *wreq,
 	 * the list.  The collector only goes nextwards and uses the lock to
 	 * remove entries off of the front.
 	 */
-	spin_lock(&wreq->lock);
+	spin_lock_bh(&wreq->lock);
 	list_add_tail(&subreq->rreq_link, &stream->subrequests);
 	if (list_is_first(&subreq->rreq_link, &stream->subrequests)) {
 		stream->front = subreq;
@@ -202,7 +202,7 @@ static void netfs_prepare_write(struct netfs_io_request *wreq,
 		}
 	}
 
-	spin_unlock(&wreq->lock);
+	spin_unlock_bh(&wreq->lock);
 
 	stream->construct = subreq;
 }