xsk: add Rx queue setup and mmap support

Another setsockopt (XDP_RX_QUEUE) is added to let the process allocate
a queue, where the kernel can pass completed Rx frames from the kernel
to user process.

The mmapping of the queue is done using the XDP_PGOFF_RX_QUEUE offset.

Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 32 insertions, 9 deletions

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index da67a3c5c1c9..92bd9b7e548f 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -31,6 +31,7 @@
 #include <linux/net.h>
 #include <linux/netdevice.h>
 #include <net/xdp_sock.h>
+#include <net/xdp.h>
 
 #include "xsk_queue.h"
 #include "xdp_umem.h"
@@ -40,14 +41,15 @@ static struct xdp_sock *xdp_sk(struct sock *sk)
 	return (struct xdp_sock *)sk;
 }
 
-static int xsk_init_queue(u32 entries, struct xsk_queue **queue)
+static int xsk_init_queue(u32 entries, struct xsk_queue **queue,
+			  bool umem_queue)
 {
 	struct xsk_queue *q;
 
 	if (entries == 0 || *queue || !is_power_of_2(entries))
 		return -EINVAL;
 
-	q = xskq_create(entries);
+	q = xskq_create(entries, umem_queue);
 	if (!q)
 		return -ENOMEM;
 
@@ -89,6 +91,22 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
 		return -ENOPROTOOPT;
 
 	switch (optname) {
+	case XDP_RX_RING:
+	{
+		struct xsk_queue **q;
+		int entries;
+
+		if (optlen < sizeof(entries))
+			return -EINVAL;
+		if (copy_from_user(&entries, optval, sizeof(entries)))
+			return -EFAULT;
+
+		mutex_lock(&xs->mutex);
+		q = &xs->rx;
+		err = xsk_init_queue(entries, q, false);
+		mutex_unlock(&xs->mutex);
+		return err;
+	}
 	case XDP_UMEM_REG:
 	{
 		struct xdp_umem_reg mr;
@@ -130,7 +148,7 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
 
 		mutex_lock(&xs->mutex);
 		q = &xs->umem->fq;
-		err = xsk_init_queue(entries, q);
+		err = xsk_init_queue(entries, q, true);
 		mutex_unlock(&xs->mutex);
 		return err;
 	}
@@ -151,13 +169,17 @@ static int xsk_mmap(struct file *file, struct socket *sock,
 	unsigned long pfn;
 	struct page *qpg;
 
-	if (!xs->umem)
-		return -EINVAL;
+	if (offset == XDP_PGOFF_RX_RING) {
+		q = xs->rx;
+	} else {
+		if (!xs->umem)
+			return -EINVAL;
 
-	if (offset == XDP_UMEM_PGOFF_FILL_RING)
-		q = xs->umem->fq;
-	else
-		return -EINVAL;
+		if (offset == XDP_UMEM_PGOFF_FILL_RING)
+			q = xs->umem->fq;
+		else
+			return -EINVAL;
+	}
 
 	if (!q)
 		return -EINVAL;
@@ -205,6 +227,7 @@ static void xsk_destruct(struct sock *sk)
 	if (!sock_flag(sk, SOCK_DEAD))
 		return;
 
+	xskq_destroy(xs->rx);
 	xdp_put_umem(xs->umem);
 
 	sk_refcnt_debug_dec(sk);