diff options
Diffstat (limited to 'include/linux/virtio.h')
| -rw-r--r-- | include/linux/virtio.h | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 260d1fcf29a..e7d10845b3c 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -41,13 +41,17 @@ struct virtqueue * Returns NULL or the "data" token handed to add_buf. * @disable_cb: disable callbacks * vq: the struct virtqueue we're talking about. + * Note that this is not necessarily synchronous, hence unreliable and only + * useful as an optimization. * @enable_cb: restart callbacks after disable_cb. * vq: the struct virtqueue we're talking about. - * This returns "false" (and doesn't re-enable) if there are pending - * buffers in the queue, to avoid a race. + * This re-enables callbacks; it returns "false" if there are pending + * buffers in the queue, to detect a possible race between the driver + * checking for more work, and enabling callbacks. * * Locking rules are straightforward: the driver is responsible for - * locking. No two operations may be invoked simultaneously. + * locking. No two operations may be invoked simultaneously, with the exception + * of @disable_cb. * * All operations can be called in any context. */ |