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Message-ID: <20081113173127.GB30811@kroah.com>
Date: Thu, 13 Nov 2008 09:31:27 -0800
From: Greg KH <greg@...ah.com>
To: Michael Ellerman <michael@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, Andrew Morton <akpm@...l.org>,
viro@...iv.linux.org.uk
Subject: Re: [PATCH] Store the relevant miscdevice in file->private_data in
misc_open()
On Thu, Nov 13, 2008 at 03:49:50PM +1100, Michael Ellerman wrote:
> Currently it's not easy to share file_operations between multiple
> instances of a miscdevice. In order to do this, the device code needs to
> store a list of all it's miscdevice instances, and when fops->open() is
> called, search the list and find the right device based on the minor
> number.
>
> However the generic miscdevice code already has a list of miscdevices,
> and uses this to find the right device in misc_open(). If misc_open()
> would store the miscdevice it found in file->private_data, then the
> device code wouldn't need to worry about storing it's own separate list
> and searching that as well.
>
> The rest of the miscdevice code does not use file->private_data, so the
> device code is still free to use file->private_data for something else
> if it wants to.
>
> Signed-off-by: Michael Ellerman <michael@...erman.id.au>
Do you have a follow-on patch for some misc device using code that would
take advantage of this change?
thanks,
greg k-h
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