[PATCH 0/2] w1 fixes for broken subsystem

[PATCH 0/2] w1 fixes for broken subsystem

[Hans-Frieder Vogt]

In recent kernels the 1-wire kernel modules do not work any more. The module 
wire got broken in 3.11-rc1 and 3.12-rc1 introduced a further problem:

1: 3.11-rc1 introduced the automatic loading of slave modules. This blocks 
modprobe, because request_module is called with a locked mutex of the w1 
master.
Loading of the slave module calls  w1_register_family, which calls in turn
w1_reconnect_slaves and there mutex_lock(&dev->mutex) will wait forever....

2: 3.12-rc1 introduced w1_bus_notify which assumes that all slaves have fops 
defined. This is not the case for e.g. w1_smem and maybe also breaks custom 
written modules.

This very small patch set is split in 2 parts:

PATCH 1/2: w1 - fix fops in w1_bus_notify
fixes problem 2 above

PATCH 2/2: w1 - call request_module with w1 master mutex unlocked
fixes problem 1 above

Please include these patches in 3.12-rc4 and in 3.11 stable.

Best regards,

Hans-Frieder Vogt                       e-mail: hfvogt <at> gmx .dot. net

Re: [PATCH 0/2] w1 fixes for broken subsystem

[Evgeniy Polyakov]

Hi

06.10.2013, 23:13, "Hans-Frieder Vogt" <hfvogt@gmx.net>:
> In recent kernels the 1-wire kernel modules do not work any more. The module
> wire got broken in 3.11-rc1 and 3.12-rc1 introduced a further problem:

Looks like I somehow missed it and bugs got in

> 1: 3.11-rc1 introduced the automatic loading of slave modules. This blocks
> modprobe, because request_module is called with a locked mutex of the w1
> master.
> Loading of the slave module calls  w1_register_family, which calls in turn
> w1_reconnect_slaves and there mutex_lock(&dev->mutex) will wait forever....

That's correct

> 2: 3.12-rc1 introduced w1_bus_notify which assumes that all slaves have fops
> defined. This is not the case for e.g. w1_smem and maybe also breaks custom
> written modules.

Isn't fops are supposed to be in the slave device?
Although they look meaningless for most of devices, I would introduce them everywhere...

But anyway, your patches fix those problems, thanks a lot.
Greg, please queue them into appropriate trees.

Acked-by: Evgeniy Polyakov <zbr@ioremap.net>

Re: [PATCH 0/2] w1 fixes for broken subsystem

[gregkh]

On Mon, Oct 07, 2013 at 12:45:44AM +0400, Evgeniy Polyakov wrote:
> Hi
> 
> 06.10.2013, 23:13, "Hans-Frieder Vogt" <hfvogt@gmx.net>:
> > In recent kernels the 1-wire kernel modules do not work any more. The module
> > wire got broken in 3.11-rc1 and 3.12-rc1 introduced a further problem:
> 
> Looks like I somehow missed it and bugs got in
> 
> > 1: 3.11-rc1 introduced the automatic loading of slave modules. This blocks
> > modprobe, because request_module is called with a locked mutex of the w1
> > master.
> > Loading of the slave module calls  w1_register_family, which calls in turn
> > w1_reconnect_slaves and there mutex_lock(&dev->mutex) will wait forever....
> 
> That's correct
> 
> > 2: 3.12-rc1 introduced w1_bus_notify which assumes that all slaves have fops
> > defined. This is not the case for e.g. w1_smem and maybe also breaks custom
> > written modules.
> 
> Isn't fops are supposed to be in the slave device?
> Although they look meaningless for most of devices, I would introduce them everywhere...
> 
> But anyway, your patches fix those problems, thanks a lot.
> Greg, please queue them into appropriate trees.
> 
> Acked-by: Evgeniy Polyakov <zbr@ioremap.net>

Thanks for reviewing this, I'll queue them up in a bit.

greg k-h