Messages in this thread | | | Date | Thu, 29 May 2008 08:45:43 +0800 | From | "Dave Young" <> | Subject | Re: [PATCH][-mm] reclassify sg_sysfs_class for lockdep |
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On Wed, May 28, 2008 at 10:40 PM, James Bottomley <James.Bottomley@hansenpartnership.com> wrote: > On Tue, 2008-05-27 at 18:10 +0800, Dave Young wrote: >> As register sg_interface, the sg_add will be called, which then will >> add device to sg_sysfs_class. This will cause lockdep warning, >> please see following email >> >> In this case the locks are from diffrent classi, one is sdev_class, >> another is sg_sysfs_class >> >> Here reclassify the sg_sysfs_class for lockdep > > This isn't really a generic solution, is it? It only works because we > currently only have two users of the interface functions, so if we > reclassify one they look separate to lockdep. It will fall over again > if we ever get another one. > > Surely the correct fix is to initialise lockdep for the mutex the same > way we did for the semaphore in class_register() (which does exactly the > same locking without triggering lockdep)? That way we'll also fix the > problem for other conversions of semaphore->mutex.
Matthew & greg did the work already.
From my original idea I don't want to do this for all classes, and I would think it as a rare case.
Regards dave
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