linux/net/xdp/xsk_queue.c
Jakub Kicinski f5bd91388e net: xsk: add a simple buffer reuse queue
XSK UMEM is strongly single producer single consumer so reuse of
frames is challenging.  Add a simple "stash" of FILL packets to
reuse for drivers to optionally make use of.  This is useful
when driver has to free (ndo_stop) or resize a ring with an active
AF_XDP ZC socket.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2018-09-25 13:13:15 -07:00

120 lines
2.4 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* XDP user-space ring structure
* Copyright(c) 2018 Intel Corporation.
*/
#include <linux/log2.h>
#include <linux/slab.h>
#include <linux/overflow.h>
#include "xsk_queue.h"
void xskq_set_umem(struct xsk_queue *q, u64 size, u64 chunk_mask)
{
if (!q)
return;
q->size = size;
q->chunk_mask = chunk_mask;
}
static u32 xskq_umem_get_ring_size(struct xsk_queue *q)
{
return sizeof(struct xdp_umem_ring) + q->nentries * sizeof(u64);
}
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;
size_t size;
q = kzalloc(sizeof(*q), GFP_KERNEL);
if (!q)
return NULL;
q->nentries = nentries;
q->ring_mask = nentries - 1;
gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN |
__GFP_COMP | __GFP_NORETRY;
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));
if (!q->ring) {
kfree(q);
return NULL;
}
return q;
}
void xskq_destroy(struct xsk_queue *q)
{
if (!q)
return;
page_frag_free(q->ring);
kfree(q);
}
struct xdp_umem_fq_reuse *xsk_reuseq_prepare(u32 nentries)
{
struct xdp_umem_fq_reuse *newq;
/* Check for overflow */
if (nentries > (u32)roundup_pow_of_two(nentries))
return NULL;
nentries = roundup_pow_of_two(nentries);
newq = kvmalloc(struct_size(newq, handles, nentries), GFP_KERNEL);
if (!newq)
return NULL;
memset(newq, 0, offsetof(typeof(*newq), handles));
newq->nentries = nentries;
return newq;
}
EXPORT_SYMBOL_GPL(xsk_reuseq_prepare);
struct xdp_umem_fq_reuse *xsk_reuseq_swap(struct xdp_umem *umem,
struct xdp_umem_fq_reuse *newq)
{
struct xdp_umem_fq_reuse *oldq = umem->fq_reuse;
if (!oldq) {
umem->fq_reuse = newq;
return NULL;
}
if (newq->nentries < oldq->length)
return newq;
memcpy(newq->handles, oldq->handles,
array_size(oldq->length, sizeof(u64)));
newq->length = oldq->length;
umem->fq_reuse = newq;
return oldq;
}
EXPORT_SYMBOL_GPL(xsk_reuseq_swap);
void xsk_reuseq_free(struct xdp_umem_fq_reuse *rq)
{
kvfree(rq);
}
EXPORT_SYMBOL_GPL(xsk_reuseq_free);
void xsk_reuseq_destroy(struct xdp_umem *umem)
{
xsk_reuseq_free(umem->fq_reuse);
umem->fq_reuse = NULL;
}