target/linux/mvebu/patches-4.4/044-net-add-a-hardware-buffer-management-helper-API.patch

   1 From: Gregory CLEMENT <gregory.clement@free-electrons.com>
   2 Date: Mon, 14 Mar 2016 09:39:04 +0100
   3 Subject: [PATCH] net: add a hardware buffer management helper API
   4
   5 This basic implementation allows to share code between driver using
   6 hardware buffer management. As the code is hardware agnostic, there is
   7 few helpers, most of the optimization brought by the an HW BM has to be
   8 done at driver level.
   9
  10 Tested-by: Sebastian Careba <nitroshift@yahoo.com>
  11 Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
  12 Signed-off-by: David S. Miller <davem@davemloft.net>
  13 ---
  14  create mode 100644 include/net/hwbm.h
  15  create mode 100644 net/core/hwbm.c
  16
  17 --- /dev/null
  18 +++ b/include/net/hwbm.h
  19 @@ -0,0 +1,28 @@
  20 +#ifndef _HWBM_H
  21 +#define _HWBM_H
  22 +
  23 +struct hwbm_pool {
  24 +       /* Capacity of the pool */
  25 +       int size;
  26 +       /* Size of the buffers managed */
  27 +       int frag_size;
  28 +       /* Number of buffers currently used by this pool */
  29 +       int buf_num;
  30 +       /* constructor called during alocation */
  31 +       int (*construct)(struct hwbm_pool *bm_pool, void *buf);
  32 +       /* protect acces to the buffer counter*/
  33 +       spinlock_t lock;
  34 +       /* private data */
  35 +       void *priv;
  36 +};
  37 +#ifdef CONFIG_HWBM
  38 +void hwbm_buf_free(struct hwbm_pool *bm_pool, void *buf);
  39 +int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp);
  40 +int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num, gfp_t gfp);
  41 +#else
  42 +void hwbm_buf_free(struct hwbm_pool *bm_pool, void *buf) {}
  43 +int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp) { return 0; }
  44 +int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num, gfp_t gfp)
  45 +{ return 0; }
  46 +#endif /* CONFIG_HWBM */
  47 +#endif /* _HWBM_H */
  48 --- a/net/Kconfig
  49 +++ b/net/Kconfig
  50 @@ -259,6 +259,9 @@ config XPS
  51         depends on SMP
  52         default y
  53
  54 +config HWBM
  55 +       bool
  56 +
  57  config CGROUP_NET_PRIO
  58         bool "Network priority cgroup"
  59         depends on CGROUPS
  60 --- a/net/core/Makefile
  61 +++ b/net/core/Makefile
  62 @@ -14,6 +14,7 @@ obj-y              += dev.o ethtool.o dev_addr_
  63  obj-$(CONFIG_SOCK_DIAG) += sock_diag.o
  64  obj-$(CONFIG_XFRM) += flow.o
  65  obj-y += net-sysfs.o
  66 +obj-$(CONFIG_HWBM) += hwbm.o
  67  obj-$(CONFIG_PROC_FS) += net-procfs.o
  68  obj-$(CONFIG_NET_PKTGEN) += pktgen.o
  69  obj-$(CONFIG_NETPOLL) += netpoll.o
  70 --- /dev/null
  71 +++ b/net/core/hwbm.c
  72 @@ -0,0 +1,87 @@
  73 +/* Support for hardware buffer manager.
  74 + *
  75 + * Copyright (C) 2016 Marvell
  76 + *
  77 + * Gregory CLEMENT <gregory.clement@free-electrons.com>
  78 + *
  79 + *  This program is free software; you can redistribute it and/or modify
  80 + *  it under the terms of the GNU General Public License as published by
  81 + *  the Free Software Foundation; either version 2 of the License, or
  82 + *  (at your option) any later version.
  83 + */
  84 +#include <linux/kernel.h>
  85 +#include <linux/printk.h>
  86 +#include <linux/skbuff.h>
  87 +#include <net/hwbm.h>
  88 +
  89 +void hwbm_buf_free(struct hwbm_pool *bm_pool, void *buf)
  90 +{
  91 +       if (likely(bm_pool->frag_size <= PAGE_SIZE))
  92 +               skb_free_frag(buf);
  93 +       else
  94 +               kfree(buf);
  95 +}
  96 +EXPORT_SYMBOL_GPL(hwbm_buf_free);
  97 +
  98 +/* Refill processing for HW buffer management */
  99 +int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp)
 100 +{
 101 +       int frag_size = bm_pool->frag_size;
 102 +       void *buf;
 103 +
 104 +       if (likely(frag_size <= PAGE_SIZE))
 105 +               buf = netdev_alloc_frag(frag_size);
 106 +       else
 107 +               buf = kmalloc(frag_size, gfp);
 108 +
 109 +       if (!buf)
 110 +               return -ENOMEM;
 111 +
 112 +       if (bm_pool->construct)
 113 +               if (bm_pool->construct(bm_pool, buf)) {
 114 +                       hwbm_buf_free(bm_pool, buf);
 115 +                       return -ENOMEM;
 116 +               }
 117 +
 118 +       return 0;
 119 +}
 120 +EXPORT_SYMBOL_GPL(hwbm_pool_refill);
 121 +
 122 +int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num, gfp_t gfp)
 123 +{
 124 +       int err, i;
 125 +       unsigned long flags;
 126 +
 127 +       spin_lock_irqsave(&bm_pool->lock, flags);
 128 +       if (bm_pool->buf_num == bm_pool->size) {
 129 +               pr_warn("pool already filled\n");
 130 +               return bm_pool->buf_num;
 131 +       }
 132 +
 133 +       if (buf_num + bm_pool->buf_num > bm_pool->size) {
 134 +               pr_warn("cannot allocate %d buffers for pool\n",
 135 +                       buf_num);
 136 +               return 0;
 137 +       }
 138 +
 139 +       if ((buf_num + bm_pool->buf_num) < bm_pool->buf_num) {
 140 +               pr_warn("Adding %d buffers to the %d current buffers will overflow\n",
 141 +                       buf_num,  bm_pool->buf_num);
 142 +               return 0;
 143 +       }
 144 +
 145 +       for (i = 0; i < buf_num; i++) {
 146 +               err = hwbm_pool_refill(bm_pool, gfp);
 147 +               if (err < 0)
 148 +                       break;
 149 +       }
 150 +
 151 +       /* Update BM driver with number of buffers added to pool */
 152 +       bm_pool->buf_num += i;
 153 +
 154 +       pr_debug("hwpm pool: %d of %d buffers added\n", i, buf_num);
 155 +       spin_unlock_irqrestore(&bm_pool->lock, flags);
 156 +
 157 +       return i;
 158 +}
 159 +EXPORT_SYMBOL_GPL(hwbm_pool_add);