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Commit 423f3832 authored by Magnus Karlsson's avatar Magnus Karlsson Committed by Alexei Starovoitov
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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: default avatarMagnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c0c77d8f

include/uapi/linux/if_xdp.h

+15 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 


/* XDP socket options */

#define XDP_UMEM_REG			3

#define XDP_UMEM_FILL_RING		4



struct xdp_umem_reg {

	__u64 addr; /* Start of packet data area */
@@ -31,4 +32,18 @@ struct xdp_umem_reg { 
	__u32 frame_headroom; /* Frame head room */

};



/* Pgoff for mmaping the rings */

#define XDP_UMEM_PGOFF_FILL_RING	0x100000000



struct xdp_ring {

	__u32 producer __attribute__((aligned(64)));

	__u32 consumer __attribute__((aligned(64)));

};



/* Used for the fill and completion queues for buffers */

struct xdp_umem_ring {

	struct xdp_ring ptrs;

	__u32 desc[0] __attribute__((aligned(64)));

};



#endif /* _LINUX_IF_XDP_H */

net/xdp/Makefile

+1 −1
Original line number Diff line number Diff line 
obj-$(CONFIG_XDP_SOCKETS) += xsk.o xdp_umem.o

obj-$(CONFIG_XDP_SOCKETS) += xsk.o xdp_umem.o xsk_queue.o

net/xdp/xdp_umem.c

+5 −0
Original line number Diff line number Diff line
@@ -65,6 +65,11 @@ static void xdp_umem_release(struct xdp_umem *umem) 
	struct task_struct *task;

	struct mm_struct *mm;



	if (umem->fq) {

		xskq_destroy(umem->fq);

		umem->fq = NULL;

	}



	if (umem->pgs) {

		xdp_umem_unpin_pages(umem);

net/xdp/xdp_umem.h

+2 −0
Original line number Diff line number Diff line
@@ -19,9 +19,11 @@ 
#include <linux/if_xdp.h>

#include <linux/workqueue.h>



#include "xsk_queue.h"

#include "xdp_umem_props.h"



struct xdp_umem {

	struct xsk_queue *fq;

	struct page **pgs;

	struct xdp_umem_props props;

	u32 npgs;

net/xdp/xsk.c

+64 −1
Original line number Diff line number Diff line
@@ -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,

};