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- From: Gregory CLEMENT <gregory.clement@free-electrons.com>
- Date: Mon, 14 Mar 2016 09:39:04 +0100
- Subject: [PATCH] net: add a hardware buffer management helper API
- This basic implementation allows to share code between driver using
- hardware buffer management. As the code is hardware agnostic, there is
- few helpers, most of the optimization brought by the an HW BM has to be
- done at driver level.
- Tested-by: Sebastian Careba <nitroshift@yahoo.com>
- Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
- Signed-off-by: David S. Miller <davem@davemloft.net>
- ---
- create mode 100644 include/net/hwbm.h
- create mode 100644 net/core/hwbm.c
- --- /dev/null
- +++ b/include/net/hwbm.h
- @@ -0,0 +1,28 @@
- +#ifndef _HWBM_H
- +#define _HWBM_H
- +
- +struct hwbm_pool {
- + /* Capacity of the pool */
- + int size;
- + /* Size of the buffers managed */
- + int frag_size;
- + /* Number of buffers currently used by this pool */
- + int buf_num;
- + /* constructor called during alocation */
- + int (*construct)(struct hwbm_pool *bm_pool, void *buf);
- + /* protect acces to the buffer counter*/
- + spinlock_t lock;
- + /* private data */
- + void *priv;
- +};
- +#ifdef CONFIG_HWBM
- +void hwbm_buf_free(struct hwbm_pool *bm_pool, void *buf);
- +int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp);
- +int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num, gfp_t gfp);
- +#else
- +void hwbm_buf_free(struct hwbm_pool *bm_pool, void *buf) {}
- +int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp) { return 0; }
- +int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num, gfp_t gfp)
- +{ return 0; }
- +#endif /* CONFIG_HWBM */
- +#endif /* _HWBM_H */
- --- a/net/Kconfig
- +++ b/net/Kconfig
- @@ -259,6 +259,9 @@ config XPS
- depends on SMP
- default y
-
- +config HWBM
- + bool
- +
- config CGROUP_NET_PRIO
- bool "Network priority cgroup"
- depends on CGROUPS
- --- a/net/core/Makefile
- +++ b/net/core/Makefile
- @@ -14,6 +14,7 @@ obj-y += dev.o ethtool.o dev_addr_
- obj-$(CONFIG_SOCK_DIAG) += sock_diag.o
- obj-$(CONFIG_XFRM) += flow.o
- obj-y += net-sysfs.o
- +obj-$(CONFIG_HWBM) += hwbm.o
- obj-$(CONFIG_PROC_FS) += net-procfs.o
- obj-$(CONFIG_NET_PKTGEN) += pktgen.o
- obj-$(CONFIG_NETPOLL) += netpoll.o
- --- /dev/null
- +++ b/net/core/hwbm.c
- @@ -0,0 +1,87 @@
- +/* Support for hardware buffer manager.
- + *
- + * Copyright (C) 2016 Marvell
- + *
- + * Gregory CLEMENT <gregory.clement@free-electrons.com>
- + *
- + * This program is free software; you can redistribute it and/or modify
- + * it under the terms of the GNU General Public License as published by
- + * the Free Software Foundation; either version 2 of the License, or
- + * (at your option) any later version.
- + */
- +#include <linux/kernel.h>
- +#include <linux/printk.h>
- +#include <linux/skbuff.h>
- +#include <net/hwbm.h>
- +
- +void hwbm_buf_free(struct hwbm_pool *bm_pool, void *buf)
- +{
- + if (likely(bm_pool->frag_size <= PAGE_SIZE))
- + skb_free_frag(buf);
- + else
- + kfree(buf);
- +}
- +EXPORT_SYMBOL_GPL(hwbm_buf_free);
- +
- +/* Refill processing for HW buffer management */
- +int hwbm_pool_refill(struct hwbm_pool *bm_pool, gfp_t gfp)
- +{
- + int frag_size = bm_pool->frag_size;
- + void *buf;
- +
- + if (likely(frag_size <= PAGE_SIZE))
- + buf = netdev_alloc_frag(frag_size);
- + else
- + buf = kmalloc(frag_size, gfp);
- +
- + if (!buf)
- + return -ENOMEM;
- +
- + if (bm_pool->construct)
- + if (bm_pool->construct(bm_pool, buf)) {
- + hwbm_buf_free(bm_pool, buf);
- + return -ENOMEM;
- + }
- +
- + return 0;
- +}
- +EXPORT_SYMBOL_GPL(hwbm_pool_refill);
- +
- +int hwbm_pool_add(struct hwbm_pool *bm_pool, unsigned int buf_num, gfp_t gfp)
- +{
- + int err, i;
- + unsigned long flags;
- +
- + spin_lock_irqsave(&bm_pool->lock, flags);
- + if (bm_pool->buf_num == bm_pool->size) {
- + pr_warn("pool already filled\n");
- + return bm_pool->buf_num;
- + }
- +
- + if (buf_num + bm_pool->buf_num > bm_pool->size) {
- + pr_warn("cannot allocate %d buffers for pool\n",
- + buf_num);
- + return 0;
- + }
- +
- + if ((buf_num + bm_pool->buf_num) < bm_pool->buf_num) {
- + pr_warn("Adding %d buffers to the %d current buffers will overflow\n",
- + buf_num, bm_pool->buf_num);
- + return 0;
- + }
- +
- + for (i = 0; i < buf_num; i++) {
- + err = hwbm_pool_refill(bm_pool, gfp);
- + if (err < 0)
- + break;
- + }
- +
- + /* Update BM driver with number of buffers added to pool */
- + bm_pool->buf_num += i;
- +
- + pr_debug("hwpm pool: %d of %d buffers added\n", i, buf_num);
- + spin_unlock_irqrestore(&bm_pool->lock, flags);
- +
- + return i;
- +}
- +EXPORT_SYMBOL_GPL(hwbm_pool_add);
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