path: root/drivers/block/aoe/aoecmd.c

/* Copyright (c) 2007 Coraid, Inc.  See COPYING for GPL terms. */
/*
 * aoecmd.c
 * Filesystem request handling methods
 */

#include <linux/ata.h>
#include <linux/slab.h>
#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/genhd.h>
#include <linux/moduleparam.h>
#include <net/net_namespace.h>
#include <asm/unaligned.h>
#include "aoe.h"

static int aoe_deadsecs = 60 * 3;
module_param(aoe_deadsecs, int, 0644);
MODULE_PARM_DESC(aoe_deadsecs, "After aoe_deadsecs seconds, give up and fail dev.");

static int aoe_maxout = 16;
module_param(aoe_maxout, int, 0644);
MODULE_PARM_DESC(aoe_maxout,
	"Only aoe_maxout outstanding packets for every MAC on eX.Y.");

static struct sk_buff *
new_skb(ulong len)
{
	struct sk_buff *skb;

	skb = alloc_skb(len, GFP_ATOMIC);
	if (skb) {
		skb_reset_mac_header(skb);
		skb_reset_network_header(skb);
		skb->protocol = __constant_htons(ETH_P_AOE);
	}
	return skb;
}

static struct frame *
getframe(struct aoetgt *t, int tag)
{
	struct frame *f, *e;

	f = t->frames;
	e = f + t->nframes;
	for (; f<e; f++)
		if (f->tag == tag)
			return f;
	return NULL;
}

/*
 * Leave the top bit clear so we have tagspace for userland.
 * The bottom 16 bits are the xmit tick for rexmit/rttavg processing.
 * This driver reserves tag -1 to mean "unused frame."
 */
static int
newtag(struct aoetgt *t)
{
	register ulong n;

	n = jiffies & 0xffff;
	return n |= (++t->lasttag & 0x7fff) << 16;
}

static int
aoehdr_atainit(struct aoedev *d, struct aoetgt *t, struct aoe_hdr *h)
{
	u32 host_tag = newtag(t);

	memcpy(h->src, t->ifp->nd->dev_addr, sizeof h->src);
	memcpy(h->dst, t->addr, sizeof h->dst);
	h->type = __constant_cpu_to_be16(ETH_P_AOE);
	h->verfl = AOE_HVER;
	h->major = cpu_to_be16(d->aoemajor);
	h->minor = d->aoeminor;
	h->cmd = AOECMD_ATA;
	h->tag = cpu_to_be32(host_tag);

	return host_tag;
}

static inline void
put_lba(struct aoe_atahdr *ah, sector_t lba)
{
	ah->lba0 = lba;
	ah->lba1 = lba >>= 8;
	ah->lba2 = lba >>= 8;
	ah->lba3 = lba >>= 8;
	ah->lba4 = lba >>= 8;
	ah->lba5 = lba >>= 8;
}

static void
ifrotate(struct aoetgt *t)
{
	t->ifp++;
	if (t->ifp >= &t->ifs[NAOEIFS] || t->ifp->nd == NULL)
		t->ifp = t->ifs;
	if (t->ifp->nd == NULL) {
		printk(KERN_INFO "aoe: no interface to rotate to\n");
		BUG();
	}
}

static void
skb_pool_put(struct aoedev *d, struct sk_buff *skb)
{
	__skb_queue_tail(&d->skbpool, skb);
}

static struct sk_buff *
skb_pool_get(struct aoedev *d)
{
	struct sk_buff *skb = skb_peek(&d->skbpool);

	if (skb && atomic_read(&skb_shinfo(skb)->dataref)