drm/nouveau/flcn/msgq: simplify msg_queue_pop() error handling

We always want at least requested size, make anything less a more direct
error condition.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/falcon/msgq.c b/drivers/gpu/drm/nouveau/nvkm/falcon/msgq.c
index ea3e7c7..15299ff 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/falcon/msgq.c
+++ b/drivers/gpu/drm/nouveau/nvkm/falcon/msgq.c
@@ -67,20 +67,14 @@ msg_queue_pop(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
        tail = queue->position;
 
        available = head - tail;
-
-       if (available == 0) {
-               nvkm_warn(subdev, "no message data available\n");
-               return 0;
-       }
-
        if (size > available) {
                nvkm_warn(subdev, "message data smaller than read request\n");
-               size = available;
+               return -EINVAL;
        }
 
        nvkm_falcon_read_dmem(priv->falcon, tail, size, 0, data);
        queue->position += ALIGN(size, QUEUE_ALIGNMENT);
-       return size;
+       return 0;
 }
 
 static int
@@ -88,19 +82,15 @@ msg_queue_read(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
               struct nv_falcon_msg *hdr)
 {
        const struct nvkm_subdev *subdev = priv->falcon->owner;
-       int ret;
+       int ret = 0;
 
        msg_queue_open(priv, queue);
 
-       if (msg_queue_empty(priv, queue)) {
-               ret = 0;
+       if (msg_queue_empty(priv, queue))
                goto close;
-       }
 
        ret = msg_queue_pop(priv, queue, hdr, HDR_SIZE);
-       if (ret >= 0 && ret != HDR_SIZE)
-               ret = -EINVAL;
-       if (ret < 0) {
+       if (ret) {
                nvkm_error(subdev, "failed to read message header: %d\n", ret);
                goto close;
        }
@@ -115,14 +105,13 @@ msg_queue_read(struct nvkm_msgqueue *priv, struct nvkm_msgqueue_queue *queue,
                u32 read_size = hdr->size - HDR_SIZE;
 
                ret = msg_queue_pop(priv, queue, (hdr + 1), read_size);
-               if (ret >= 0 && ret != read_size)
-                       ret = -EINVAL;
-               if (ret < 0) {
+               if (ret) {
                        nvkm_error(subdev, "failed to read message: %d\n", ret);
                        goto close;
                }
        }
 
+       ret = 1;
 close:
        msg_queue_close(priv, queue, (ret >= 0));
        return ret;