xsk: add umem completion queue support and mmap

Here, we add another setsockopt for registered user memory (umem) called XDP_UMEM_COMPLETION_QUEUE. Using this socket option, the process can ask the kernel to allocate a queue (ring buffer) and also mmap it (XDP_UMEM_PGOFF_COMPLETION_QUEUE) into the process. The queue is used to explicitly pass ownership of umem frames from the kernel to user process. This will be used by the TX path to tell user space that a certain frame has been transmitted and user space can use it for something else, if it wishes.

Magnus Karlsson committed 8 years ago

Commit fe230831 parent 02671e24 files · +15 −2Browse files

Unified · Split

4 files

include/uapi/linux/if_xdp.h +2 −0
net/xdp/xdp_umem.c +6 −1
net/xdp/xdp_umem.h +1 −0
net/xdp/xsk.c +6 −1

include/uapi/linux/if_xdp.h+2−0

@@ -36,6 +36,7 @@ struct sockaddr_xdp { · 35 unmodified lines
36	36	#define XDP_RX_RING 1
37	37	#define XDP_UMEM_REG 3
38	38	#define XDP_UMEM_FILL_RING 4
	39	+#define XDP_UMEM_COMPLETION_RING 5
39	40
40	41	struct xdp_umem_reg {
41	42	__u64 addr; /* Start of packet data area */
@@ -47,6 +48,7 @@ struct xdp_umem_reg { · 5 unmodified lines
47	48	/* Pgoff for mmaping the rings */
48	49	#define XDP_PGOFF_RX_RING 0
49	50	#define XDP_UMEM_PGOFF_FILL_RING 0x100000000
	51	+#define XDP_UMEM_PGOFF_COMPLETION_RING 0x180000000
50	52
51	53	struct xdp_desc {
52	54	__u32 idx;

net/xdp/xdp_umem.c+6−1

@@ -70,6 +70,11 @@ static void xdp_umem_release(struct xdp_umem *umem) · 69 unmodified lines
70	70	umem->fq = NULL;
71	71	}
72	72
	73	+ if (umem->cq) {
	74	+ xskq_destroy(umem->cq);
	75	+ umem->cq = NULL;
	76	+ }
	77	+
73	78	if (umem->pgs) {
74	79	xdp_umem_unpin_pages(umem);
75	80
@@ -251,5 +256,5 @@ out: · 175 unmodified lines
251	256
252	257	bool xdp_umem_validate_queues(struct xdp_umem *umem)
253	258	{
254		− return umem->fq;
	259	+ return (umem->fq && umem->cq);
255	260	}

net/xdp/xdp_umem.h+1−0

@@ -24,6 +24,7 @@ · 23 unmodified lines
24	24
25	25	struct xdp_umem {
26	26	struct xsk_queue *fq;
	27	+ struct xsk_queue *cq;
27	28	struct page **pgs;
28	29	struct xdp_umem_props props;
29	30	u32 npgs;

net/xdp/xsk.c+6−1

@@ -255,6 +255,7 @@ static int xsk_bind(struct socket sock, struct sockaddr addr, int addr_len) · 254 unmodified lines
255	255	} else {
256	256	/* This xsk has its own umem. */
257	257	xskq_set_umem(xs->umem->fq, &xs->umem->props);
	258	+ xskq_set_umem(xs->umem->cq, &xs->umem->props);
258	259	}
259	260
260	261	/* Rebind? */
@@ -334,6 +335,7 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, · 73 unmodified lines
334	335	return 0;
335	336	}
336	337	case XDP_UMEM_FILL_RING:
	338	+ case XDP_UMEM_COMPLETION_RING:
337	339	{
338	340	struct xsk_queue **q;
339	341	int entries;
@@ -345,7 +347,8 @@ static int xsk_setsockopt(struct socket *sock, int level, int optname, · 5 unmodified lines
345	347	return -EFAULT;
346	348
347	349	mutex_lock(&xs->mutex);
348		− q = &xs->umem->fq;
	350	+ q = (optname == XDP_UMEM_FILL_RING) ? &xs->umem->fq :
	351	+ &xs->umem->cq;
349	352	err = xsk_init_queue(entries, q, true);
350	353	mutex_unlock(&xs->mutex);
351	354	return err;
@@ -375,6 +378,8 @@ static int xsk_mmap(struct file file, struct socket sock, · 23 unmodified lines
375	378
376	379	if (offset == XDP_UMEM_PGOFF_FILL_RING)
377	380	q = xs->umem->fq;
	381	+ else if (offset == XDP_UMEM_PGOFF_COMPLETION_RING)
	382	+ q = xs->umem->cq;
378	383	else
379	384	return -EINVAL;
380	385	}