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Commit 8cb2d8bf authored by Gregory CLEMENT's avatar Gregory CLEMENT Committed by David S. Miller
Browse files

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: default avatarSebastian Careba <nitroshift@yahoo.com>
Signed-off-by: default avatarGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent dc35a10f

include/net/hwbm.h

0 → 100644
+28 −0
Original line number Diff line number Diff line 
#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 */

net/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -253,6 +253,9 @@ config XPS 
	depends on SMP

	default y



config HWBM

       bool



config SOCK_CGROUP_DATA

	bool

	default n

net/core/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -25,4 +25,5 @@ obj-$(CONFIG_CGROUP_NET_PRIO) += netprio_cgroup.o 
obj-$(CONFIG_CGROUP_NET_CLASSID) += netclassid_cgroup.o

obj-$(CONFIG_LWTUNNEL) += lwtunnel.o

obj-$(CONFIG_DST_CACHE) += dst_cache.o

obj-$(CONFIG_HWBM) += hwbm.o

obj-$(CONFIG_NET_DEVLINK) += devlink.o

net/core/hwbm.c

0 → 100644
+87 −0
Original line number Diff line number Diff line 
/* 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);