Better document macros for DMA tracking. Add an
explicit one for DMA in progress instead of
relying on user supplying len != 1.
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
drivers/vhost/net.c | 3 ++-
drivers/vhost/vhost.c | 2 +-
drivers/vhost/vhost.h | 12 +++++++++---
3 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 072cbba..f80ae5f 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -237,7 +237,8 @@ static void handle_tx(struct vhost_net *net)
} else {
struct ubuf_info *ubuf = &vq->ubuf_info[head];
- vq->heads[vq->upend_idx].len = len;
+ vq->heads[vq->upend_idx].len =
+ VHOST_DMA_IN_PROGRESS;
ubuf->callback = vhost_zerocopy_callback;
ubuf->ctx = vq->ubufs;
ubuf->desc = vq->upend_idx;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 73d08db..f23cf89 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1606,7 +1606,7 @@ void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool status)
struct vhost_virtqueue *vq = ubufs->vq;
vhost_poll_queue(&vq->poll);
- /* set len = 1 to mark this desc buffers done DMA */
+ /* set len to mark this desc buffers done DMA */
vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN;
kref_put(&ubufs->kref, vhost_zerocopy_done_signal);
}
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 2de4ce2..b6538ee 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -13,9 +13,15 @@
#include <linux/virtio_ring.h>
#include <linux/atomic.h>
-/* This is for zerocopy, used buffer len is set to 1 when lower device DMA
- * done */
-#define VHOST_DMA_DONE_LEN 1
+/*
+ * For transmit, used buffer len is unused; we override it to track buffer
+ * status internally; used for zerocopy tx only.
+ */
+/* Lower device DMA done */
+#define VHOST_DMA_DONE_LEN 2
+/* Lower device DMA in progress */
+#define VHOST_DMA_IN_PROGRESS 1
+/* Buffer unused */
#define VHOST_DMA_CLEAR_LEN 0
struct vhost_device;
--
MST
--
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