[PATCH v2 3/3] virtiofs: Do not stall hiprio FORGET dispatch after dropping one request

[Li Wang <liwang@kylinos.cn>]

send_forget_request() documents return value 1 as caller should wait;
virtio_fs_hiprio_dispatch_work() treats any non-zero return as a signal to
stop processing the rest of queued_reqs.

When virtqueue_add_outbuf() fails with a non-recoverable error we kfree the
forget but left ret negative, so the worker returned early and stranded
subsequent queued FORGETs.  Return 0 after dropping so the queue keeps
draining.

Signed-off-by: Li Wang <liwang@kylinos.cn>
---
 fs/fuse/virtio_fs.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c
index 7e4c3fa6ab57..e5d3d58a760c 100644
--- a/fs/fuse/virtio_fs.c
+++ b/fs/fuse/virtio_fs.c
@@ -652,6 +652,12 @@ static int send_forget_request(struct virtio_fs_vq *fsvq,
 			kfree(forget);
 			if (in_flight)
 				dec_in_flight_req(fsvq);
+			/*
+			 * send_forget_request() returns 1 to mean "stop draining
+			 * queued_reqs for now".  A negative value is also non-zero
+			 * and would stall the worker after one dropped forget.
+			 */
+			ret = 0;
 		}
 		goto out;
 	}
-- 
2.34.1