xsk: add umem fill queue support and mmap
Here, we add another setsockopt for registered user memory (umem)
called XDP_UMEM_FILL_QUEUE. Using this socket option, the process can
ask the kernel to allocate a queue (ring buffer) and also mmap it
(XDP_UMEM_PGOFF_FILL_QUEUE) into the process.
The queue is used to explicitly pass ownership of umem frames from the
user process to the kernel. These frames will in a later patch be
filled in with Rx packet data by the kernel.
v2: Fixed potential crash in xsk_mmap.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 84e0e86..da67a3c 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -32,6 +32,7 @@
#include <linux/netdevice.h>
#include <net/xdp_sock.h>
+#include "xsk_queue.h"
#include "xdp_umem.h"
static struct xdp_sock *xdp_sk(struct sock *sk)
@@ -39,6 +40,21 @@ 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)
+{
+ struct xsk_queue *q;
+
+ if (entries == 0 || *queue || !is_power_of_2(entries))
+ return -EINVAL;
+
+ q = xskq_create(entries);
+ if (!q)
+ return -ENOMEM;
+
+ *queue = q;
+ return 0;
+}
+
static int xsk_release(struct socket *sock)
{
struct sock *sk = sock->sk;
@@ -101,6 +117,23 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
mutex_unlock(&xs->mutex);
return 0;
}
+ case XDP_UMEM_FILL_RING:
+ {
+ struct xsk_queue **q;
+ int entries;
+
+ if (!xs->umem)
+ return -EINVAL;
+
+ if (copy_from_user(&entries, optval, sizeof(entries)))
+ return -EFAULT;
+
+ mutex_lock(&xs->mutex);
+ q = &xs->umem->fq;
+ err = xsk_init_queue(entries, q);
+ mutex_unlock(&xs->mutex);
+ return err;
+ }
default:
break;
}
@@ -108,6 +141,36 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname,
return -ENOPROTOOPT;
}
+static int xsk_mmap(struct file *file, struct socket *sock,
+ struct vm_area_struct *vma)
+{
+ unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
+ unsigned long size = vma->vm_end - vma->vm_start;
+ struct xdp_sock *xs = xdp_sk(sock->sk);
+ struct xsk_queue *q = NULL;
+ unsigned long pfn;
+ struct page *qpg;
+
+ if (!xs->umem)
+ return -EINVAL;
+
+ if (offset == XDP_UMEM_PGOFF_FILL_RING)
+ q = xs->umem->fq;
+ else
+ return -EINVAL;
+
+ if (!q)
+ return -EINVAL;
+
+ qpg = virt_to_head_page(q->ring);
+ if (size > (PAGE_SIZE << compound_order(qpg)))
+ return -EINVAL;
+
+ pfn = virt_to_phys(q->ring) >> PAGE_SHIFT;
+ return remap_pfn_range(vma, vma->vm_start, pfn,
+ size, vma->vm_page_prot);
+}
+
static struct proto xsk_proto = {
.name = "XDP",
.owner = THIS_MODULE,
@@ -131,7 +194,7 @@ static const struct proto_ops xsk_proto_ops = {
.getsockopt = sock_no_getsockopt,
.sendmsg = sock_no_sendmsg,
.recvmsg = sock_no_recvmsg,
- .mmap = sock_no_mmap,
+ .mmap = xsk_mmap,
.sendpage = sock_no_sendpage,
};
