aoecmd.c

来自「LINUX 2.6.17.4的源码」· C语言 代码 · 共 709 行 · 第 1/2 页

/* Copyright (c) 2004 Coraid, Inc.  See COPYING for GPL terms. */
/*
 * aoecmd.c
 * Filesystem request handling methods
 */

#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/genhd.h>
#include <asm/unaligned.h>
#include "aoe.h"

#define TIMERTICK (HZ / 10)
#define MINTIMER (2 * TIMERTICK)
#define MAXTIMER (HZ << 1)
#define MAXWAIT (60 * 3)	/* After MAXWAIT seconds, give up and fail dev */

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

	skb = alloc_skb(len, GFP_ATOMIC);
	if (skb) {
		skb->nh.raw = skb->mac.raw = skb->data;
		skb->dev = if_dev;
		skb->protocol = __constant_htons(ETH_P_AOE);
		skb->priority = 0;
		skb_put(skb, len);
		memset(skb->head, 0, len);
		skb->next = skb->prev = NULL;

		/* tell the network layer not to perform IP checksums
		 * or to get the NIC to do it
		 */
		skb->ip_summed = CHECKSUM_NONE;
	}
	return skb;
}

static struct sk_buff *
skb_prepare(struct aoedev *d, struct frame *f)
{
	struct sk_buff *skb;
	char *p;

	skb = new_skb(d->ifp, f->ndata + f->writedatalen);
	if (!skb) {
		printk(KERN_INFO "aoe: skb_prepare: failure to allocate skb\n");
		return NULL;
	}

	p = skb->mac.raw;
	memcpy(p, f->data, f->ndata);

	if (f->writedatalen) {
		p += sizeof(struct aoe_hdr) + sizeof(struct aoe_atahdr);
		memcpy(p, f->bufaddr, f->writedatalen);
	}

	return skb;
}

static struct frame *
getframe(struct aoedev *d, int tag)
{
	struct frame *f, *e;

	f = d->frames;
	e = f + d->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 aoedev *d)
{
	register ulong n;

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

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

	memcpy(h->src, d->ifp->dev_addr, sizeof h->src);
	memcpy(h->dst, d->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 void
aoecmd_ata_rw(struct aoedev *d, struct frame *f)
{
	struct aoe_hdr *h;
	struct aoe_atahdr *ah;
	struct buf *buf;
	struct sk_buff *skb;
	ulong bcnt;
	register sector_t sector;
	char writebit, extbit;

	writebit = 0x10;
	extbit = 0x4;

	buf = d->inprocess;

	sector = buf->sector;
	bcnt = buf->bv_resid;
	if (bcnt > MAXATADATA)
		bcnt = MAXATADATA;

	/* initialize the headers & frame */
	h = (struct aoe_hdr *) f->data;
	ah = (struct aoe_atahdr *) (h+1);
	f->ndata = sizeof *h + sizeof *ah;
	memset(h, 0, f->ndata);
	f->tag = aoehdr_atainit(d, h);
	f->waited = 0;
	f->buf = buf;
	f->bufaddr = buf->bufaddr;

	/* set up ata header */
	ah->scnt = bcnt >> 9;
	ah->lba0 = sector;
	ah->lba1 = sector >>= 8;
	ah->lba2 = sector >>= 8;
	ah->lba3 = sector >>= 8;
	if (d->flags & DEVFL_EXT) {
		ah->aflags |= AOEAFL_EXT;
		ah->lba4 = sector >>= 8;
		ah->lba5 = sector >>= 8;
	} else {
		extbit = 0;
		ah->lba3 &= 0x0f;
		ah->lba3 |= 0xe0;	/* LBA bit + obsolete 0xa0 */
	}

	if (bio_data_dir(buf->bio) == WRITE) {
		ah->aflags |= AOEAFL_WRITE;
		f->writedatalen = bcnt;
	} else {
		writebit = 0;
		f->writedatalen = 0;
	}

	ah->cmdstat = WIN_READ | writebit | extbit;

	/* mark all tracking fields and load out */
	buf->nframesout += 1;
	buf->bufaddr += bcnt;
	buf->bv_resid -= bcnt;
/* printk(KERN_INFO "aoe: bv_resid=%ld\n", buf->bv_resid); */
	buf->resid -= bcnt;
	buf->sector += bcnt >> 9;
	if (buf->resid == 0) {
		d->inprocess = NULL;
	} else if (buf->bv_resid == 0) {
		buf->bv++;
		buf->bv_resid = buf->bv->bv_len;
		buf->bufaddr = page_address(buf->bv->bv_page) + buf->bv->bv_offset;
	}

	skb = skb_prepare(d, f);
	if (skb) {
		skb->next = NULL;
		if (d->sendq_hd)
			d->sendq_tl->next = skb;
		else
			d->sendq_hd = skb;
		d->sendq_tl = skb;
	}
}

/* some callers cannot sleep, and they can call this function,
 * transmitting the packets later, when interrupts are on
 */
static struct sk_buff *
aoecmd_cfg_pkts(ushort aoemajor, unsigned char aoeminor, struct sk_buff **tail)
{
	struct aoe_hdr *h;
	struct aoe_cfghdr *ch;
	struct sk_buff *skb, *sl, *sl_tail;
	struct net_device *ifp;

	sl = sl_tail = NULL;

	read_lock(&dev_base_lock);
	for (ifp = dev_base; ifp; dev_put(ifp), ifp = ifp->next) {
		dev_hold(ifp);
		if (!is_aoe_netif(ifp))
			continue;

		skb = new_skb(ifp, sizeof *h + sizeof *ch);
		if (skb == NULL) {
			printk(KERN_INFO "aoe: aoecmd_cfg: skb alloc failure\n");
			continue;
		}
		if (sl_tail == NULL)
			sl_tail = skb;
		h = (struct aoe_hdr *) skb->mac.raw;
		memset(h, 0, sizeof *h + sizeof *ch);

		memset(h->dst, 0xff, sizeof h->dst);
		memcpy(h->src, ifp->dev_addr, sizeof h->src);
		h->type = __constant_cpu_to_be16(ETH_P_AOE);
		h->verfl = AOE_HVER;
		h->major = cpu_to_be16(aoemajor);
		h->minor = aoeminor;
		h->cmd = AOECMD_CFG;

		skb->next = sl;
		sl = skb;
	}
	read_unlock(&dev_base_lock);

	if (tail != NULL)
		*tail = sl_tail;
	return sl;
}

/* enters with d->lock held */
void
aoecmd_work(struct aoedev *d)
{
	struct frame *f;
	struct buf *buf;

	if (d->flags & DEVFL_PAUSE) {
		if (!aoedev_isbusy(d))
			d->sendq_hd = aoecmd_cfg_pkts(d->aoemajor,
						d->aoeminor, &d->sendq_tl);
		return;
	}

loop:
	f = getframe(d, FREETAG);
	if (f == NULL)
		return;
	if (d->inprocess == NULL) {
		if (list_empty(&d->bufq))
			return;
		buf = container_of(d->bufq.next, struct buf, bufs);
		list_del(d->bufq.next);
/*printk(KERN_INFO "aoecmd_work: bi_size=%ld\n", buf->bio->bi_size); */
		d->inprocess = buf;
	}
	aoecmd_ata_rw(d, f);
	goto loop;
}

static void
rexmit(struct aoedev *d, struct frame *f)
{
	struct sk_buff *skb;
	struct aoe_hdr *h;
	char buf[128];
	u32 n;

	n = newtag(d);

	snprintf(buf, sizeof buf,
		"%15s e%ld.%ld oldtag=%08x@%08lx newtag=%08x\n",
		"retransmit",
		d->aoemajor, d->aoeminor, f->tag, jiffies, n);
	aoechr_error(buf);

	h = (struct aoe_hdr *) f->data;
	f->tag = n;
	h->tag = cpu_to_be32(n);
	memcpy(h->dst, d->addr, sizeof h->dst);
	memcpy(h->src, d->ifp->dev_addr, sizeof h->src);

	skb = skb_prepare(d, f);
	if (skb) {
		skb->next = NULL;
		if (d->sendq_hd)
			d->sendq_tl->next = skb;
		else
			d->sendq_hd = skb;
		d->sendq_tl = skb;
	}
}

static int
tsince(int tag)
{
	int n;

	n = jiffies & 0xffff;
	n -= tag & 0xffff;
	if (n < 0)
		n += 1<<16;
	return n;
}

static void
rexmit_timer(ulong vp)
{
	struct aoedev *d;
	struct frame *f, *e;
	struct sk_buff *sl;
	register long timeout;
	ulong flags, n;

	d = (struct aoedev *) vp;
	sl = NULL;

	/* timeout is always ~150% of the moving average */
	timeout = d->rttavg;
	timeout += timeout >> 1;

	spin_lock_irqsave(&d->lock, flags);

	if (d->flags & DEVFL_TKILL) {
		spin_unlock_irqrestore(&d->lock, flags);
		return;
	}
	f = d->frames;
	e = f + d->nframes;
	for (; f<e; f++) {
		if (f->tag != FREETAG && tsince(f->tag) >= timeout) {
			n = f->waited += timeout;
			n /= HZ;
			if (n > MAXWAIT) { /* waited too long.  device failure. */
				aoedev_downdev(d);
				break;
			}
			rexmit(d, f);
		}
	}

	sl = d->sendq_hd;
	d->sendq_hd = d->sendq_tl = NULL;
	if (sl) {
		n = d->rttavg <<= 1;
		if (n > MAXTIMER)