[PATCH RFC v7 07/14] fixup! vhost: format-independent API for used buffers

Michael S. Tsirkin
2020-06-10T11:36:30Z

---
drivers/vhost/vhost.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index e5763d81bf0f..7a587b13095c 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2421,7 +2421,7 @@ int vhost_get_avail_buf(struct vhost_virtqueue *vq, struct vhost_buf *buf,
err:
unfetch_descs(vq);

- return ret ? ret : vq->num;
+ return ret;
}
EXPORT_SYMBOL_GPL(vhost_get_avail_buf);

@@ -2433,6 +2433,27 @@ void vhost_discard_avail_bufs(struct vhost_virtqueue *vq,
}
EXPORT_SYMBOL_GPL(vhost_discard_avail_bufs);

+/* This function returns the descriptor number found, or vq->num (which is
+ * never a valid descriptor number) if none was found. A negative code is
+ * returned on error. */
+int vhost_get_vq_desc(struct vhost_virtqueue *vq,
+ struct iovec iov[], unsigned int iov_size,
+ unsigned int *out_num, unsigned int *in_num,
+ struct vhost_log *log, unsigned int *log_num)
+{
+ struct vhost_buf buf;
+ int ret = vhost_get_avail_buf(vq, &buf,
+ iov, iov_size, out_num, in_num,
+ log, log_num);
+
+ if (likely(ret > 0))
+ return buf->id;
+ if (likely(!ret))
+ return vq->num;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
+
/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
{
--
MST