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>

diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index 94785f5..db9a321 100644 (file)
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -18,11 +18,15 @@
 #include <linux/mutex.h>
 #include <net/sock.h>
 
+struct net_device;
+struct xsk_queue;
 struct xdp_umem;
 
 struct xdp_sock {
        /* struct sock must be the first member of struct xdp_sock */
        struct sock sk;
+       struct xsk_queue *rx;
+       struct net_device *dev;
        struct xdp_umem *umem;
        /* Protects multiple processes in the control path */
        struct mutex mutex;

diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index 975661e..6532455 100644 (file)
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -22,6 +22,7 @@
 #include <linux/types.h>
 
 /* XDP socket options */
+#define XDP_RX_RING                    1
 #define XDP_UMEM_REG                   3
 #define XDP_UMEM_FILL_RING             4
 
@@ -33,13 +34,28 @@ struct xdp_umem_reg {
 };
 
 /* Pgoff for mmaping the rings */
+#define XDP_PGOFF_RX_RING                        0
 #define XDP_UMEM_PGOFF_FILL_RING       0x100000000
 
+struct xdp_desc {
+       __u32 idx;
+       __u32 len;
+       __u16 offset;
+       __u8 flags;
+       __u8 padding[5];
+};
+
 struct xdp_ring {
        __u32 producer __attribute__((aligned(64)));
        __u32 consumer __attribute__((aligned(64)));
 };
 
+/* Used for the RX and TX queues for packets */
+struct xdp_rxtx_ring {
+       struct xdp_ring ptrs;
+       struct xdp_desc desc[0] __attribute__((aligned(64)));
+};
+
 /* Used for the fill and completion queues for buffers */
 struct xdp_umem_ring {
        struct xdp_ring ptrs;

diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index da67a3c..92bd9b7 100644 (file)
--- 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);

diff --git a/net/xdp/xsk_queue.c b/net/xdp/xsk_queue.c
index 23da4f2..894f9f8 100644 (file)
--- a/net/xdp/xsk_queue.c
+++ b/net/xdp/xsk_queue.c
@@ -21,7 +21,13 @@ static u32 xskq_umem_get_ring_size(struct xsk_queue *q)
        return sizeof(struct xdp_umem_ring) + q->nentries * sizeof(u32);
 }
 
-struct xsk_queue *xskq_create(u32 nentries)
+static u32 xskq_rxtx_get_ring_size(struct xsk_queue *q)
+{
+       return (sizeof(struct xdp_ring) +
+               q->nentries * sizeof(struct xdp_desc));
+}
+
+struct xsk_queue *xskq_create(u32 nentries, bool umem_queue)
 {
        struct xsk_queue *q;
        gfp_t gfp_flags;
@@ -36,7 +42,8 @@ struct xsk_queue *xskq_create(u32 nentries)
 
        gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN |
                    __GFP_COMP  | __GFP_NORETRY;
-       size = xskq_umem_get_ring_size(q);
+       size = umem_queue ? xskq_umem_get_ring_size(q) :
+              xskq_rxtx_get_ring_size(q);
 
        q->ring = (struct xdp_ring *)__get_free_pages(gfp_flags,
                                                      get_order(size));

diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
index 7eb556b..5439fa3 100644 (file)
--- a/net/xdp/xsk_queue.h
+++ b/net/xdp/xsk_queue.h
@@ -32,7 +32,7 @@ struct xsk_queue {
        u64 invalid_descs;
 };
 
-struct xsk_queue *xskq_create(u32 nentries);
+struct xsk_queue *xskq_create(u32 nentries, bool umem_queue);
 void xskq_destroy(struct xsk_queue *q);
 
 #endif /* _LINUX_XSK_QUEUE_H */