Re: [PATCH] firmware: avoiding multiple replication for same firmware file

[David Woodhouse <dwmw2@infradead.org>]

On Fri, 2008-08-01 at 11:30 +0530, Jaswinder Singh wrote:
> Now when request_firmware will be called it will check whether firmware
> is already allocated or not. If already allocated then it provide handle
> of old firmware handle and increase count of firmware.
> 
> release_firmware will decrease count of firmware, if count is one only then
> firmware will be release.

I like this. It means that when you have multiple similar devices, you
only need one copy of the firmware in memory for _all_ of them. Because
we've now made fw->data constant, we know it's safe to share them now.

I wonder if we should change the implementation of 'built-in firmware'
to use your new implementation -- just set the use count on the built-in
firmware to 1 when we start up, and then it should never go away.

Unless we're _really_ clever with linker tricks it would mean we'd have
an init function which takes the built-in stuff and builds it into the
linked list, but I think that might be worth the runtime simplification.

-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse@intel.com                              Intel Corporation