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

  cd43e26f071524647e660706b784ebcbefbd2e44

  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>

diff --git a/drivers/block/aoe/aoe.h b/drivers/block/aoe/aoe.h
index 5e41e6dd657b9a7326ba1347346c8147c428f3c2..db195abad69889e4d499bde162ff5e818601f3b2 100644 (file)
--- a/drivers/block/aoe/aoe.h
+++ b/drivers/block/aoe/aoe.h
@@ -155,7 +155,7 @@ struct aoedev {
        u16 fw_ver;             /* version of blade's firmware */
        struct work_struct work;/* disk create work struct */
        struct gendisk *gd;
-       struct request_queue blkq;
+       struct request_queue *blkq;
        struct hd_geometry geo; 
        sector_t ssize;
        struct timer_list timer;

diff --git a/drivers/block/aoe/aoeblk.c b/drivers/block/aoe/aoeblk.c
index 2307a271bdc99e91b5c410083383a0595c4c08d0..1e15889c4b9819f837076c1b17df34fc8ef881c2 100644 (file)
--- a/drivers/block/aoe/aoeblk.c
+++ b/drivers/block/aoe/aoeblk.c
@@ -264,9 +264,12 @@ aoeblk_gdalloc(void *vp)
                goto err_disk;
        }
 
-       blk_queue_make_request(&d->blkq, aoeblk_make_request);
-       if (bdi_init(&d->blkq.backing_dev_info))
+       d->blkq = blk_alloc_queue(GFP_KERNEL);
+       if (!d->blkq)
                goto err_mempool;
+       blk_queue_make_request(d->blkq, aoeblk_make_request);
+       if (bdi_init(&d->blkq->backing_dev_info))
+               goto err_blkq;
        spin_lock_irqsave(&d->lock, flags);
        gd->major = AOE_MAJOR;
        gd->first_minor = d->sysminor * AOE_PARTITIONS;
@@ -276,7 +279,7 @@ aoeblk_gdalloc(void *vp)
        snprintf(gd->disk_name, sizeof gd->disk_name, "etherd/e%ld.%d",
                d->aoemajor, d->aoeminor);
 
-       gd->queue = &d->blkq;
+       gd->queue = d->blkq;
        d->gd = gd;
        d->flags &= ~DEVFL_GDALLOC;
        d->flags |= DEVFL_UP;
@@ -287,6 +290,9 @@ aoeblk_gdalloc(void *vp)
        aoedisk_add_sysfs(d);
        return;
 
+err_blkq:
+       blk_cleanup_queue(d->blkq);
+       d->blkq = NULL;
 err_mempool:
        mempool_destroy(d->bufpool);
 err_disk:

diff --git a/drivers/block/aoe/aoedev.c b/drivers/block/aoe/aoedev.c
index eeea477d96016596ccd729a6f75d37d5e3d30a0e..fa67027789aab80ca8c11deccad4e2d3ec225697 100644 (file)
--- a/drivers/block/aoe/aoedev.c
+++ b/drivers/block/aoe/aoedev.c
@@ -113,6 +113,7 @@ aoedev_freedev(struct aoedev *d)
        if (d->bufpool)
                mempool_destroy(d->bufpool);
        skbpoolfree(d);
+       blk_cleanup_queue(d->blkq);
        kfree(d);
 }