[PATCH net-next v2 1/7] 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 <xuanz...@linux.alibaba.com>
---
 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 5b94907..b452ade 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -914,6 +914,7 @@ 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 eaa8386..2dcfa54 100644
--- a/include/net/xsk_buff_pool.h
+++ b/include/net/xsk_buff_pool.h
@@ -108,6 +108,7 @@ 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 20598ee..6d0cc9f 100644
--- a/net/xdp/xsk_buff_pool.c
+++ b/net/xdp/xsk_buff_pool.c
@@ -166,12 +166,13 @@ 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;
@@ -535,6 +536,13 @@ 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