[PATCH netdev 1/5] xsk: support get page for drv

[Xuan Zhuo]

For some drivers, such as virtio-net, we do not configure dma when
binding xsk. We will get the page when sending.

This patch participates in a field need_dma during the setup pool. If
the device does not use dma, this value should be set to false.

And a function xsk_buff_raw_get_page is added to get the page based on
addr in drv.

Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
 include/linux/netdevice.h   |  1 +
 include/net/xdp_sock_drv.h  | 10 ++++++++++
 include/net/xsk_buff_pool.h |  1 +
 net/xdp/xsk_buff_pool.c     | 10 +++++++++-
 4 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7bf1679..b8baef9 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -915,6 +915,7 @@ struct netdev_bpf {
 		struct {
 			struct xsk_buff_pool *pool;
 			u16 queue_id;
+			bool need_dma;
 		} xsk;
 	};
 };
diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h
index 4e295541..e9c7e25 100644
--- a/include/net/xdp_sock_drv.h
+++ b/include/net/xdp_sock_drv.h
@@ -100,6 +100,11 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 	return xp_raw_get_data(pool, addr);
 }
 
+static inline struct page *xsk_buff_raw_get_page(struct xsk_buff_pool *pool, u64 addr)
+{
+	return xp_raw_get_page(pool, addr);
+}
+
 static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool)
 {
 	struct xdp_buff_xsk *xskb = container_of(xdp, struct xdp_buff_xsk, xdp);
@@ -232,6 +237,11 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 	return NULL;
 }
 
+static inline struct page *xsk_buff_raw_get_page(struct xsk_buff_pool *pool, u64 addr)
+{
+	return NULL;
+}
+
 static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool)
 {
 }
diff --git a/include/net/xsk_buff_pool.h b/include/net/xsk_buff_pool.h
index 01755b8..54e461d 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -103,6 +103,7 @@ int xp_dma_map(struct xsk_buff_pool *pool, struct device *dev,
 bool xp_can_alloc(struct xsk_buff_pool *pool, u32 count);
 void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr);
 dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr);
+struct page *xp_raw_get_page(struct xsk_buff_pool *pool, u64 addr);
 static inline dma_addr_t xp_get_dma(struct xdp_buff_xsk *xskb)
 {
 	return xskb->dma;
diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c
index 67a4494..9bb058f 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -167,12 +167,13 @@ static int __xp_assign_dev(struct xsk_buff_pool *pool,
 	bpf.command = XDP_SETUP_XSK_POOL;
 	bpf.xsk.pool = pool;
 	bpf.xsk.queue_id = queue_id;
+	bpf.xsk.need_dma = true;
 
 	err = netdev->netdev_ops->ndo_bpf(netdev, &bpf);
 	if (err)
 		goto err_unreg_pool;
 
-	if (!pool->dma_pages) {
+	if (bpf.xsk.need_dma && !pool->dma_pages) {
 		WARN(1, "Driver did not DMA map zero-copy buffers");
 		err = -EINVAL;
 		goto err_unreg_xsk;
@@ -536,6 +537,13 @@ void *xp_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 }
 EXPORT_SYMBOL(xp_raw_get_data);
 
+struct page *xp_raw_get_page(struct xsk_buff_pool *pool, u64 addr)
+{
+	addr = pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
+	return pool->umem->pgs[addr >> PAGE_SHIFT];
+}
+EXPORT_SYMBOL(xp_raw_get_page);
+
 dma_addr_t xp_raw_get_dma(struct xsk_buff_pool *pool, u64 addr)
 {
 	addr = pool->unaligned ? xp_unaligned_add_offset_to_addr(addr) : addr;
-- 
1.8.3.1