[bpf-next RFC 1/3] xsk: add xsk_umem_consume_tx_virtual.

[William Tu]

Currently the xsk_umem_consume_tx expects only the physical NICs so
the api returns a dma address.  This patch introduce the new function
to return the virtual address, when XSK is used by a virtual device.

Signed-off-by: William Tu <u9012...@gmail.com>
---
 include/net/xdp_sock.h |  7 +++++++
 net/xdp/xsk.c          | 24 ++++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index 13acb9803a6d..8de6b8456945 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -81,6 +81,7 @@ u64 *xsk_umem_peek_addr(struct xdp_umem *umem, u64 *addr);
 void xsk_umem_discard_addr(struct xdp_umem *umem);
 void xsk_umem_complete_tx(struct xdp_umem *umem, u32 nb_entries);
 bool xsk_umem_consume_tx(struct xdp_umem *umem, dma_addr_t *dma, u32 *len);
+bool xsk_umem_consume_tx_virtual(struct xdp_umem *umem, char **addr, u32 *len);
 void xsk_umem_consume_tx_done(struct xdp_umem *umem);
 struct xdp_umem_fq_reuse *xsk_reuseq_prepare(u32 nentries);
 struct xdp_umem_fq_reuse *xsk_reuseq_swap(struct xdp_umem *umem,
@@ -165,6 +166,12 @@ static inline bool xsk_umem_consume_tx(struct xdp_umem 
*umem, dma_addr_t *dma,
        return false;
 }
 
+static inline bool xsk_umem_consume_tx_virtual(struct xdp_umem *umem,
+                                              char **dma, u32 *len)
+{
+       return false;
+}
+
 static inline void xsk_umem_consume_tx_done(struct xdp_umem *umem)
 {
 }
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 07156f43d295..379f5e9d0c81 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -197,6 +197,30 @@ bool xsk_umem_consume_tx(struct xdp_umem *umem, dma_addr_t 
*dma, u32 *len)
 }
 EXPORT_SYMBOL(xsk_umem_consume_tx);
 
+bool xsk_umem_consume_tx_virtual(struct xdp_umem *umem, char **addr, u32 *len)
+{
+       struct xdp_desc desc;
+       struct xdp_sock *xs;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(xs, &umem->xsk_list, list) {
+               if (!xskq_peek_desc(xs->tx, &desc))
+                        continue;
+               if (xskq_produce_addr_lazy(umem->cq, desc.addr))
+                       goto out;
+
+               *addr = xdp_umem_get_data(umem, desc.addr);
+               *len = desc.len;
+               xskq_discard_desc(xs->tx);
+               rcu_read_unlock();
+               return true;
+       }
+out:
+       rcu_read_unlock();
+       return false;
+}
+EXPORT_SYMBOL(xsk_umem_consume_tx_virtual);
+
 static int xsk_zc_xmit(struct sock *sk)
 {
        struct xdp_sock *xs = xdp_sk(sk);
-- 
2.7.4