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Commit 3f0f0133 authored by Ed L. Cashin's avatar Ed L. Cashin Committed by Linus Torvalds
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aoe: use packets that work with the smallest-MTU local interface 



Users with several network interfaces dedicated to AoE generally do not
configure them to support different-sized AoE data payloads on purpose.

For a given AoE target, there will be a set of local network interfaces
that can reach it.  Using only the payload that will fit in the
smallest-sized MTU of all those local interfaces greatly simplifies the
driver, especially in failure scenarios.

Signed-off-by: default avatarEd Cashin <ecashin@coraid.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent eb086ec5

drivers/block/aoe/aoe.h

+4 −3
Original line number Diff line number Diff line
@@ -125,9 +125,8 @@ struct frame { 


struct aoeif {

	struct net_device *nd;

	unsigned char lost;

	unsigned char lostjumbo;

	ushort maxbcnt;

	ulong lost;

	int bcnt;

};



struct aoetgt {
@@ -144,6 +143,7 @@ struct aoetgt { 
	u16 useme;

	ulong falloc;

	ulong lastwadj;		/* last window adjustment */

	int minbcnt;

	int wpkts, rpkts;

};
@@ -172,6 +172,7 @@ struct aoedev { 
		struct bio *nxbio;

		struct request *rq;

	} ip;

	ulong maxbcnt;

	struct aoetgt *targets[NTARGETS];

	struct aoetgt **tgt;	/* target in use when working */

	struct aoetgt *htgt;	/* target needing rexmit assistance */

drivers/block/aoe/aoecmd.c

+83 −68
Original line number Diff line number Diff line
@@ -119,16 +119,18 @@ put_lba(struct aoe_atahdr *ah, sector_t lba) 
	ah->lba5 = lba >>= 8;

}



static void

static struct aoeif *

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();

	}

	struct aoeif *ifp;



	ifp = t->ifp;

	ifp++;

	if (ifp >= &t->ifs[NAOEIFS] || ifp->nd == NULL)

		ifp = t->ifs;

	if (ifp->nd == NULL)

		return NULL;

	return t->ifp = ifp;

}



static void
@@ -232,8 +234,8 @@ newframe(struct aoedev *d) 
		&& t->ifp->nd) {

			f = newtframe(d, t);

			if (f) {

				d->tgt = tt;

				ifrotate(t);

				d->tgt = tt;

				return f;

			}

		}
@@ -300,7 +302,7 @@ aoecmd_ata_rw(struct aoedev *d) 
		return 0;

	t = *d->tgt;

	bv = buf->bv;

	bcnt = t->ifp->maxbcnt;

	bcnt = d->maxbcnt;

	if (bcnt == 0)

		bcnt = DEFAULTBCNT;

	if (bcnt > buf->resid)
@@ -431,9 +433,14 @@ resend(struct aoedev *d, struct frame *f) 
	u32 n;



	t = f->t;

	ifrotate(t);

	n = newtag(t);

	skb = f->skb;

	if (ifrotate(t) == NULL) {

		/* probably can't happen, but set it up to fail anyway */

		pr_info("aoe: resend: no interfaces to rotate to.\n");

		ktcomplete(f, NULL);

		return;

	}

	h = (struct aoe_hdr *) skb_mac_header(skb);

	ah = (struct aoe_atahdr *) (h+1);
@@ -483,21 +490,6 @@ getif(struct aoetgt *t, struct net_device *nd) 
	return NULL;

}



static struct aoeif *

addif(struct aoetgt *t, struct net_device *nd)

{

	struct aoeif *p;



	p = getif(t, NULL);

	if (!p)

		return NULL;

	p->nd = nd;

	p->maxbcnt = DEFAULTBCNT;

	p->lost = 0;

	p->lostjumbo = 0;

	return p;

}



static void

ejectif(struct aoetgt *t, struct aoeif *ifp)

{
@@ -546,7 +538,11 @@ sthtith(struct aoedev *d) 
			resend(d, nf);

		}

	}

	/* he's clean, he's useless.  take away his interfaces */

	/* We've cleaned up the outstanding so take away his

	 * interfaces so he won't be used.  We should remove him from

	 * the target array here, but cleaning up a target is

	 * involved.  PUNT!

	 */

	memset(ht->ifs, 0, sizeof ht->ifs);

	d->htgt = NULL;

	return 1;
@@ -1015,11 +1011,8 @@ noskb: if (buf) 
	case ATA_CMD_PIO_WRITE_EXT:

		spin_lock_irq(&d->lock);

		ifp = getif(t, skb->dev);

		if (ifp) {

		if (ifp)

			ifp->lost = 0;

			if (n > DEFAULTBCNT)

				ifp->lostjumbo = 0;

		}

		if (d->htgt == t) /* I'll help myself, thank you. */

			d->htgt = NULL;

		spin_unlock_irq(&d->lock);
@@ -1292,6 +1285,56 @@ addtgt(struct aoedev *d, char *addr, ulong nframes) 
	return *tt = t;

}



static void

setdbcnt(struct aoedev *d)

{

	struct aoetgt **t, **e;

	int bcnt = 0;



	t = d->targets;

	e = t + NTARGETS;

	for (; t < e && *t; t++)

		if (bcnt == 0 || bcnt > (*t)->minbcnt)

			bcnt = (*t)->minbcnt;

	if (bcnt != d->maxbcnt) {

		d->maxbcnt = bcnt;

		pr_info("aoe: e%ld.%d: setting %d byte data frames\n",

			d->aoemajor, d->aoeminor, bcnt);

	}

}



static void

setifbcnt(struct aoetgt *t, struct net_device *nd, int bcnt)

{

	struct aoedev *d;

	struct aoeif *p, *e;

	int minbcnt;



	d = t->d;

	minbcnt = bcnt;

	p = t->ifs;

	e = p + NAOEIFS;

	for (; p < e; p++) {

		if (p->nd == NULL)

			break;		/* end of the valid interfaces */

		if (p->nd == nd) {

			p->bcnt = bcnt;	/* we're updating */

			nd = NULL;

		} else if (minbcnt > p->bcnt)

			minbcnt = p->bcnt; /* find the min interface */

	}

	if (nd) {

		if (p == e) {

			pr_err("aoe: device setifbcnt failure; too many interfaces.\n");

			return;

		}

		p->nd = nd;

		p->bcnt = bcnt;

	}

	t->minbcnt = minbcnt;

	setdbcnt(d);

}



void

aoecmd_cfg_rsp(struct sk_buff *skb)

{
@@ -1299,7 +1342,6 @@ aoecmd_cfg_rsp(struct sk_buff *skb) 
	struct aoe_hdr *h;

	struct aoe_cfghdr *ch;

	struct aoetgt *t;

	struct aoeif *ifp;

	ulong flags, sysminor, aoemajor;

	struct sk_buff *sl;

	struct sk_buff_head queue;
@@ -1345,32 +1387,13 @@ aoecmd_cfg_rsp(struct sk_buff *skb) 
		if (!t)

			goto bail;

	}

	ifp = getif(t, skb->dev);

	if (!ifp) {

		ifp = addif(t, skb->dev);

		if (!ifp) {

			printk(KERN_INFO

				"aoe: device addif failure; "

				"too many interfaces?\n");

			goto bail;

		}

	}

	if (ifp->maxbcnt) {

		n = ifp->nd->mtu;

	n = skb->dev->mtu;

	n -= sizeof(struct aoe_hdr) + sizeof(struct aoe_atahdr);

	n /= 512;

	if (n > ch->scnt)

		n = ch->scnt;

	n = n ? n * 512 : DEFAULTBCNT;

		if (n != ifp->maxbcnt) {

			printk(KERN_INFO

				"aoe: e%ld.%d: setting %d%s%s:%pm\n",

				d->aoemajor, d->aoeminor, n,

				" byte data frames on ", ifp->nd->name,

				t->addr);

			ifp->maxbcnt = n;

		}

	}

	setifbcnt(t, skb->dev, n);



	/* don't change users' perspective */

	if (d->nopen == 0) {
@@ -1391,22 +1414,14 @@ void 
aoecmd_cleanslate(struct aoedev *d)

{

	struct aoetgt **t, **te;

	struct aoeif *p, *e;



	d->mintimer = MINTIMER;

	d->maxbcnt = 0;



	t = d->targets;

	te = t + NTARGETS;

	for (; t < te && *t; t++) {

	for (; t < te && *t; t++)

		(*t)->maxout = (*t)->nframes;

		p = (*t)->ifs;

		e = p + NAOEIFS;

		for (; p < e; p++) {

			p->lostjumbo = 0;

			p->lost = 0;

			p->maxbcnt = DEFAULTBCNT;

		}

	}

}



void