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Subject: Re: Cannot rmmod after call to add_mtd_blktrans_dev
From: Maxim Levitsky <maximlevitsky@gmail.com>
To: Jarkko Lavinen <jarkko.lavinen@nokia.com>
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References: <20100908122039.GA25005@angel.research.nokia.com>
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Date: Sun, 19 Sep 2010 01:17:42 +0200
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Cc: linux-mtd@lists.infradead.org, David Woodhouse <david.woodhouse@intel.com>
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On Wed, 2010-09-08 at 17:43 +0300, Maxim Levitsky wrote: 
> On Wed, 2010-09-08 at 15:20 +0300, Jarkko Lavinen wrote: 
> > I am working with mtdswap driver which uses
> > add_mtd_blktrans_dev().  Once I call add_mtd_blktrans_dev() the
> > driver module reference count is 1 and I cannot remove the
> > module.
> > 
> > Before commit 048d871 (mtd: blktrans: Hotplug fixes) the module
> > ref count was 0 after loading. Ref count was increased only when
> > thedevice was opened and it was possible to remove the module if
> > none was using it.
> > 
> > After the 048d871 it doesn't seem to be possible to remove
> > drivers which use add_mtd_blktrans_dev().  Many drivers similar
> > to ftl have ftl_remove_dev() which calls del_mtd_blktrans_dev()
> > that would put the module but cannot be called unless the ref
> > count is already 0.
> > 
> > Jarkko Lavinen
> 
> My fault, I take a good look at how to fix that differently.
> Best regards,
> Maxim Levitsky

Please test the patch I have just posted on linux-mtd.

Best regards,
Maxim Levitsky