Introduce helper virtqueue_get_dma_premapped(), then the driver
can know whether dma unmap is needed.

Signed-off-by: Xuan Zhuo <xuanz...@linux.alibaba.com>
---
 drivers/net/virtio/main.c       | 22 +++++++++-------------
 drivers/net/virtio/virtio_net.h |  3 ---
 drivers/virtio/virtio_ring.c    | 22 ++++++++++++++++++++++
 include/linux/virtio.h          |  1 +
 4 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
index b95a59884687..70d2a4e7b43f 100644
--- a/drivers/net/virtio/main.c
+++ b/drivers/net/virtio/main.c
@@ -478,7 +478,7 @@ static void *virtnet_rq_get_buf(struct virtnet_rq *rq, u32 
*len, void **ctx)
        void *buf;
 
        buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
-       if (buf && rq->do_dma)
+       if (buf && virtqueue_get_dma_premapped(rq->vq))
                virtnet_rq_unmap(rq, buf, *len);
 
        return buf;
@@ -491,7 +491,7 @@ static void virtnet_rq_init_one_sg(struct virtnet_rq *rq, 
void *buf, u32 len)
        u32 offset;
        void *head;
 
-       if (!rq->do_dma) {
+       if (!virtqueue_get_dma_premapped(rq->vq)) {
                sg_init_one(rq->sg, buf, len);
                return;
        }
@@ -521,7 +521,7 @@ static void *virtnet_rq_alloc(struct virtnet_rq *rq, u32 
size, gfp_t gfp)
 
        head = page_address(alloc_frag->page);
 
-       if (rq->do_dma) {
+       if (virtqueue_get_dma_premapped(rq->vq)) {
                dma = head;
 
                /* new pages */
@@ -575,12 +575,8 @@ static void virtnet_rq_set_premapped(struct virtnet_info 
*vi)
        if (!vi->mergeable_rx_bufs && vi->big_packets)
                return;
 
-       for (i = 0; i < vi->max_queue_pairs; i++) {
-               if (virtqueue_set_dma_premapped(vi->rq[i].vq))
-                       continue;
-
-               vi->rq[i].do_dma = true;
-       }
+       for (i = 0; i < vi->max_queue_pairs; i++)
+               virtqueue_set_dma_premapped(vi->rq[i].vq);
 }
 
 static void free_old_xmit(struct virtnet_sq *sq, bool in_napi)
@@ -1638,7 +1634,7 @@ static int add_recvbuf_small(struct virtnet_info *vi, 
struct virtnet_rq *rq,
 
        err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
        if (err < 0) {
-               if (rq->do_dma)
+               if (virtqueue_get_dma_premapped(rq->vq))
                        virtnet_rq_unmap(rq, buf, 0);
                put_page(virt_to_head_page(buf));
        }
@@ -1753,7 +1749,7 @@ static int add_recvbuf_mergeable(struct virtnet_info *vi,
        ctx = mergeable_len_to_ctx(len + room, headroom);
        err = virtqueue_add_inbuf_ctx(rq->vq, rq->sg, 1, buf, ctx, gfp);
        if (err < 0) {
-               if (rq->do_dma)
+               if (virtqueue_get_dma_premapped(rq->vq))
                        virtnet_rq_unmap(rq, buf, 0);
                put_page(virt_to_head_page(buf));
        }
@@ -3822,7 +3818,7 @@ static void free_receive_page_frags(struct virtnet_info 
*vi)
        int i;
        for (i = 0; i < vi->max_queue_pairs; i++)
                if (vi->rq[i].alloc_frag.page) {
-                       if (vi->rq[i].do_dma && vi->rq[i].last_dma)
+                       if (virtqueue_get_dma_premapped(vi->rq[i].vq) && 
vi->rq[i].last_dma)
                                virtnet_rq_unmap(&vi->rq[i], 
vi->rq[i].last_dma, 0);
                        put_page(vi->rq[i].alloc_frag.page);
                }
@@ -3850,7 +3846,7 @@ static void virtnet_rq_free_unused_bufs(struct virtqueue 
*vq)
        rq = &vi->rq[i];
 
        while ((buf = virtqueue_detach_unused_buf(vq)) != NULL) {
-               if (rq->do_dma)
+               if (virtqueue_get_dma_premapped(rq->vq))
                        virtnet_rq_unmap(rq, buf, 0);
 
                virtnet_rq_free_buf(vi, rq, buf);
diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
index ebf9f344648a..2ca968db6153 100644
--- a/drivers/net/virtio/virtio_net.h
+++ b/drivers/net/virtio/virtio_net.h
@@ -104,9 +104,6 @@ struct virtnet_rq {
 
        /* Record the last dma info to free after new pages is allocated. */
        struct virtnet_rq_dma *last_dma;
-
-       /* Do dma by self */
-       bool do_dma;
 };
 
 struct virtnet_info {
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index a2d6aea551a7..e4a4b9323a37 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2905,6 +2905,28 @@ int virtqueue_set_dma_premapped(struct virtqueue *_vq)
 }
 EXPORT_SYMBOL_GPL(virtqueue_set_dma_premapped);
 
+/**
+ * virtqueue_get_dma_premapped - get the vring premapped mode
+ * @_vq: the struct virtqueue we're talking about.
+ *
+ * Get the premapped mode of the vq.
+ *
+ * Returns bool for the vq premapped mode.
+ */
+bool virtqueue_get_dma_premapped(struct virtqueue *_vq)
+{
+       struct vring_virtqueue *vq = to_vvq(_vq);
+       bool premapped;
+
+       START_USE(vq);
+       premapped = vq->premapped;
+       END_USE(vq);
+
+       return premapped;
+
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_dma_premapped);
+
 /**
  * virtqueue_reset - detach and recycle all unused buffers
  * @_vq: the struct virtqueue we're talking about.
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 2596f0e7e395..3e9a2bb75af6 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -98,6 +98,7 @@ bool virtqueue_enable_cb(struct virtqueue *vq);
 unsigned virtqueue_enable_cb_prepare(struct virtqueue *vq);
 
 int virtqueue_set_dma_premapped(struct virtqueue *_vq);
+bool virtqueue_get_dma_premapped(struct virtqueue *_vq);
 
 bool virtqueue_poll(struct virtqueue *vq, unsigned);
 
-- 
2.32.0.3.g01195cf9f


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