Messages in this thread Patch in this message | | | From | Bartlomiej Zolnierkiewicz <> | Subject | Re: [regression] Re: 2.6.26-rc6: pcmcia stopped working | Date | Sat, 5 Jul 2008 14:48:40 +0200 |
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Hi,
On Thursday 26 June 2008, Pavel Machek wrote: > Hi! > > > > Hmm, hitting sysrq-w produces no blocked task until I eject pcmcia > > > card. Backtrace there is: > > > > > > Greg, I believe some traces lead to sysfs, can you help here? > > > > ide_unregister() does not complete :-(. > > > > device_unregister(&hwif->gendev); > > + printk("ide_unregister: waiting for rel_comp\n"); > > wait_for_completion(&hwif->gendev_rel_comp); > > > > ...that wait_for_completion never returns.
[...]
Thanks for narrowing it down to wait_for_completion() call, it was an useful hint.
From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Subject: [PATCH] ide: fix hwif->gendev refcounting
class->dev_release is called by device_release() iff dev->release is not present so ide_port_class_release() is never called and the last hwif->gendev reference is not dropped.
Fix it by removing ide_port_class_release() and get_device() call from ide_register_port() (device_create_drvdata() takes a hwif->gendev reference anyway).
This patch fixes hang on wait_for_completion(&hwif->gendev_rel_comp) in ide_unregister() reported by Pavel Machek.
Cc: Pavel Machek <pavel@suse.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Greg KH <greg@kroah.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> --- drivers/ide/ide-probe.c | 2 -- drivers/ide/ide.c | 8 -------- 2 files changed, 10 deletions(-)
Index: b/drivers/ide/ide-probe.c =================================================================== --- a/drivers/ide/ide-probe.c +++ b/drivers/ide/ide-probe.c @@ -646,8 +646,6 @@ static int ide_register_port(ide_hwif_t goto out; } - get_device(&hwif->gendev); - hwif->portdev = device_create_drvdata(ide_port_class, &hwif->gendev, MKDEV(0, 0), hwif, hwif->name); if (IS_ERR(hwif->portdev)) { Index: b/drivers/ide/ide.c =================================================================== --- a/drivers/ide/ide.c +++ b/drivers/ide/ide.c @@ -1094,13 +1094,6 @@ struct bus_type ide_bus_type = { EXPORT_SYMBOL_GPL(ide_bus_type); -static void ide_port_class_release(struct device *portdev) -{ - ide_hwif_t *hwif = dev_get_drvdata(portdev); - - put_device(&hwif->gendev); -} - int ide_vlb_clk; EXPORT_SYMBOL_GPL(ide_vlb_clk); @@ -1305,7 +1298,6 @@ static int __init ide_init(void) ret = PTR_ERR(ide_port_class); goto out_port_class; } - ide_port_class->dev_release = ide_port_class_release; init_ide_data();
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