linux/drivers/block/aoe/aoedev.c
Ed Cashin 7135a71b19 aoe: allocate unused request_queue for sysfs
Andy Whitcroft reported an oops in aoe triggered by use of an
incorrectly initialised request_queue object:

  [ 2645.959090] kobject '<NULL>' (ffff880059ca22c0): tried to add
		an uninitialized object, something is seriously wrong.
  [ 2645.959104] Pid: 6, comm: events/0 Not tainted 2.6.31-5-generic #24-Ubuntu
  [ 2645.959107] Call Trace:
  [ 2645.959139] [<ffffffff8126ca2f>] kobject_add+0x5f/0x70
  [ 2645.959151] [<ffffffff8125b4ab>] blk_register_queue+0x8b/0xf0
  [ 2645.959155] [<ffffffff8126043f>] add_disk+0x8f/0x160
  [ 2645.959161] [<ffffffffa01673c4>] aoeblk_gdalloc+0x164/0x1c0 [aoe]

The request queue of an aoe device is not used but can be allocated in
code that does not sleep.

Bruno bisected this regression down to

  cd43e26f07

  block: Expose stacked device queues in sysfs

"This seems to generate /sys/block/$device/queue and its contents for
 everyone who is using queues, not just for those queues that have a
 non-NULL queue->request_fn."

Addresses http://bugs.launchpad.net/bugs/410198
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13942

Note that embedding a queue inside another object has always been
an illegal construct, since the queues are reference counted and
must persist until the last reference is dropped. So aoe was
always buggy in this respect (Jens).

Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Andy Whitcroft <apw@canonical.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Bruno Premont <bonbons@linux-vserver.org>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-09 14:10:18 +02:00

278 lines
5.3 KiB
C

/* Copyright (c) 2007 Coraid, Inc. See COPYING for GPL terms. */
/*
* aoedev.c
* AoE device utility functions; maintains device list.
*/
#include <linux/hdreg.h>
#include <linux/blkdev.h>
#include <linux/netdevice.h>
#include <linux/delay.h>
#include "aoe.h"
static void dummy_timer(ulong);
static void aoedev_freedev(struct aoedev *);
static void freetgt(struct aoedev *d, struct aoetgt *t);
static void skbpoolfree(struct aoedev *d);
static struct aoedev *devlist;
static DEFINE_SPINLOCK(devlist_lock);
struct aoedev *
aoedev_by_aoeaddr(int maj, int min)
{
struct aoedev *d;
ulong flags;
spin_lock_irqsave(&devlist_lock, flags);
for (d=devlist; d; d=d->next)
if (d->aoemajor == maj && d->aoeminor == min)
break;
spin_unlock_irqrestore(&devlist_lock, flags);
return d;
}
static void
dummy_timer(ulong vp)
{
struct aoedev *d;
d = (struct aoedev *)vp;
if (d->flags & DEVFL_TKILL)
return;
d->timer.expires = jiffies + HZ;
add_timer(&d->timer);
}
void
aoedev_downdev(struct aoedev *d)
{
struct aoetgt **t, **te;
struct frame *f, *e;
struct buf *buf;
struct bio *bio;
t = d->targets;
te = t + NTARGETS;
for (; t < te && *t; t++) {
f = (*t)->frames;
e = f + (*t)->nframes;
for (; f < e; f->tag = FREETAG, f->buf = NULL, f++) {
if (f->tag == FREETAG || f->buf == NULL)
continue;
buf = f->buf;
bio = buf->bio;
if (--buf->nframesout == 0
&& buf != d->inprocess) {
mempool_free(buf, d->bufpool);
bio_endio(bio, -EIO);
}
}
(*t)->maxout = (*t)->nframes;
(*t)->nout = 0;
}
buf = d->inprocess;
if (buf) {
bio = buf->bio;
mempool_free(buf, d->bufpool);
bio_endio(bio, -EIO);
}
d->inprocess = NULL;
d->htgt = NULL;
while (!list_empty(&d->bufq)) {
buf = container_of(d->bufq.next, struct buf, bufs);
list_del(d->bufq.next);
bio = buf->bio;
mempool_free(buf, d->bufpool);
bio_endio(bio, -EIO);
}
if (d->gd)
set_capacity(d->gd, 0);
d->flags &= ~DEVFL_UP;
}
static void
aoedev_freedev(struct aoedev *d)
{
struct aoetgt **t, **e;
if (d->gd) {
aoedisk_rm_sysfs(d);
del_gendisk(d->gd);
put_disk(d->gd);
}
t = d->targets;
e = t + NTARGETS;
for (; t < e && *t; t++)
freetgt(d, *t);
if (d->bufpool)
mempool_destroy(d->bufpool);
skbpoolfree(d);
blk_cleanup_queue(d->blkq);
kfree(d);
}
int
aoedev_flush(const char __user *str, size_t cnt)
{
ulong flags;
struct aoedev *d, **dd;
struct aoedev *rmd = NULL;
char buf[16];
int all = 0;
if (cnt >= 3) {
if (cnt > sizeof buf)
cnt = sizeof buf;
if (copy_from_user(buf, str, cnt))
return -EFAULT;
all = !strncmp(buf, "all", 3);
}
flush_scheduled_work();
spin_lock_irqsave(&devlist_lock, flags);
dd = &devlist;
while ((d = *dd)) {
spin_lock(&d->lock);
if ((!all && (d->flags & DEVFL_UP))
|| (d->flags & (DEVFL_GDALLOC|DEVFL_NEWSIZE))
|| d->nopen) {
spin_unlock(&d->lock);
dd = &d->next;
continue;
}
*dd = d->next;
aoedev_downdev(d);
d->flags |= DEVFL_TKILL;
spin_unlock(&d->lock);
d->next = rmd;
rmd = d;
}
spin_unlock_irqrestore(&devlist_lock, flags);
while ((d = rmd)) {
rmd = d->next;
del_timer_sync(&d->timer);
aoedev_freedev(d); /* must be able to sleep */
}
return 0;
}
/* I'm not really sure that this is a realistic problem, but if the
network driver goes gonzo let's just leak memory after complaining. */
static void
skbfree(struct sk_buff *skb)
{
enum { Sms = 100, Tms = 3*1000};
int i = Tms / Sms;
if (skb == NULL)
return;
while (atomic_read(&skb_shinfo(skb)->dataref) != 1 && i-- > 0)
msleep(Sms);
if (i < 0) {
printk(KERN_ERR
"aoe: %s holds ref: %s\n",
skb->dev ? skb->dev->name : "netif",
"cannot free skb -- memory leaked.");
return;
}
skb_shinfo(skb)->nr_frags = skb->data_len = 0;
skb_trim(skb, 0);
dev_kfree_skb(skb);
}
static void
skbpoolfree(struct aoedev *d)
{
struct sk_buff *skb, *tmp;
skb_queue_walk_safe(&d->skbpool, skb, tmp)
skbfree(skb);
__skb_queue_head_init(&d->skbpool);
}
/* find it or malloc it */
struct aoedev *
aoedev_by_sysminor_m(ulong sysminor)
{
struct aoedev *d;
ulong flags;
spin_lock_irqsave(&devlist_lock, flags);
for (d=devlist; d; d=d->next)
if (d->sysminor == sysminor)
break;
if (d)
goto out;
d = kcalloc(1, sizeof *d, GFP_ATOMIC);
if (!d)
goto out;
INIT_WORK(&d->work, aoecmd_sleepwork);
spin_lock_init(&d->lock);
skb_queue_head_init(&d->sendq);
skb_queue_head_init(&d->skbpool);
init_timer(&d->timer);
d->timer.data = (ulong) d;
d->timer.function = dummy_timer;
d->timer.expires = jiffies + HZ;
add_timer(&d->timer);
d->bufpool = NULL; /* defer to aoeblk_gdalloc */
d->tgt = d->targets;
INIT_LIST_HEAD(&d->bufq);
d->sysminor = sysminor;
d->aoemajor = AOEMAJOR(sysminor);
d->aoeminor = AOEMINOR(sysminor);
d->mintimer = MINTIMER;
d->next = devlist;
devlist = d;
out:
spin_unlock_irqrestore(&devlist_lock, flags);
return d;
}
static void
freetgt(struct aoedev *d, struct aoetgt *t)
{
struct frame *f, *e;
f = t->frames;
e = f + t->nframes;
for (; f < e; f++)
skbfree(f->skb);
kfree(t->frames);
kfree(t);
}
void
aoedev_exit(void)
{
struct aoedev *d;
ulong flags;
flush_scheduled_work();
while ((d = devlist)) {
devlist = d->next;
spin_lock_irqsave(&d->lock, flags);
aoedev_downdev(d);
d->flags |= DEVFL_TKILL;
spin_unlock_irqrestore(&d->lock, flags);
del_timer_sync(&d->timer);
aoedev_freedev(d);
}
}
int __init
aoedev_init(void)
{
return 0;
}