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aoe: use packets that work with the smallest-MTU local interface
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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: Ed Cashin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@ecashin @torvalds
ecashin authored and torvalds committed Oct 5, 2012
1 parent eb086ec commit 3f0f013
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Showing 2 changed files with 87 additions and 71 deletions.
7 changes: 4 additions & 3 deletions drivers/block/aoe/aoe.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 {
Expand All @@ -144,6 +143,7 @@ struct aoetgt {
u16 useme;
ulong falloc;
ulong lastwadj; /* last window adjustment */
int minbcnt;
int wpkts, rpkts;
};

Expand Down Expand Up @@ -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 */
Expand Down
151 changes: 83 additions & 68 deletions drivers/block/aoe/aoecmd.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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;
}
}
Expand Down Expand Up @@ -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)
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -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)
{
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -1292,14 +1285,63 @@ 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)
{
struct aoedev *d;
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;
Expand Down Expand Up @@ -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 -= 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;
}
}
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;
setifbcnt(t, skb->dev, n);

/* don't change users' perspective */
if (d->nopen == 0) {
Expand All @@ -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
Expand Down

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