net/xdp/xsk_queue.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* XDP user-space ring structure
   3  * Copyright(c) 2018 Intel Corporation.
   4  */
   5
   6 #include <linux/log2.h>
   7 #include <linux/slab.h>
   8 #include <linux/overflow.h>
   9
  10 #include "xsk_queue.h"
  11
  12 void xskq_set_umem(struct xsk_queue *q, u64 size, u64 chunk_mask)
  13 {
  14         if (!q)
  15                 return;
  16
  17         q->size = size;
  18         q->chunk_mask = chunk_mask;
  19 }
  20
  21 static size_t xskq_get_ring_size(struct xsk_queue *q, bool umem_queue)
  22 {
  23         struct xdp_umem_ring *umem_ring;
  24         struct xdp_rxtx_ring *rxtx_ring;
  25
  26         if (umem_queue)
  27                 return struct_size(umem_ring, desc, q->nentries);
  28         return struct_size(rxtx_ring, desc, q->nentries);
  29 }
  30
  31 struct xsk_queue *xskq_create(u32 nentries, bool umem_queue)
  32 {
  33         struct xsk_queue *q;
  34         gfp_t gfp_flags;
  35         size_t size;
  36
  37         q = kzalloc(sizeof(*q), GFP_KERNEL);
  38         if (!q)
  39                 return NULL;
  40
  41         q->nentries = nentries;
  42         q->ring_mask = nentries - 1;
  43
  44         gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN |
  45                     __GFP_COMP  | __GFP_NORETRY;
  46         size = xskq_get_ring_size(q, umem_queue);
  47
  48         q->ring = (struct xdp_ring *)__get_free_pages(gfp_flags,
  49                                                       get_order(size));
  50         if (!q->ring) {
  51                 kfree(q);
  52                 return NULL;
  53         }
  54
  55         return q;
  56 }
  57
  58 void xskq_destroy(struct xsk_queue *q)
  59 {
  60         if (!q)
  61                 return;
  62
  63         page_frag_free(q->ring);
  64         kfree(q);
  65 }
  66
  67 struct xdp_umem_fq_reuse *xsk_reuseq_prepare(u32 nentries)
  68 {
  69         struct xdp_umem_fq_reuse *newq;
  70
  71         /* Check for overflow */
  72         if (nentries > (u32)roundup_pow_of_two(nentries))
  73                 return NULL;
  74         nentries = roundup_pow_of_two(nentries);
  75
  76         newq = kvmalloc(struct_size(newq, handles, nentries), GFP_KERNEL);
  77         if (!newq)
  78                 return NULL;
  79         memset(newq, 0, offsetof(typeof(*newq), handles));
  80
  81         newq->nentries = nentries;
  82         return newq;
  83 }
  84 EXPORT_SYMBOL_GPL(xsk_reuseq_prepare);
  85
  86 struct xdp_umem_fq_reuse *xsk_reuseq_swap(struct xdp_umem *umem,
  87                                           struct xdp_umem_fq_reuse *newq)
  88 {
  89         struct xdp_umem_fq_reuse *oldq = umem->fq_reuse;
  90
  91         if (!oldq) {
  92                 umem->fq_reuse = newq;
  93                 return NULL;
  94         }
  95
  96         if (newq->nentries < oldq->length)
  97                 return newq;
  98
  99         memcpy(newq->handles, oldq->handles,
 100                array_size(oldq->length, sizeof(u64)));
 101         newq->length = oldq->length;
 102
 103         umem->fq_reuse = newq;
 104         return oldq;
 105 }
 106 EXPORT_SYMBOL_GPL(xsk_reuseq_swap);
 107
 108 void xsk_reuseq_free(struct xdp_umem_fq_reuse *rq)
 109 {
 110         kvfree(rq);
 111 }
 112 EXPORT_SYMBOL_GPL(xsk_reuseq_free);
 113
 114 void xsk_reuseq_destroy(struct xdp_umem *umem)
 115 {
 116         xsk_reuseq_free(umem->fq_reuse);
 117         umem->fq_reuse = NULL;
 118 }