linux-kernel - Re: [PATCH] firmware: remove request_firmware_into

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Message-ID: <20170627173711.GJ18666@tuxbook>
Date:   Tue, 27 Jun 2017 10:37:11 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     "Luis R. Rodriguez" <mcgrof@...nel.org>,
        Daniel Wagner <wagi@...om.org>,
        David Woodhouse <dwmw2@...radead.org>, rafal@...ecki.pl,
        Arend van Spriel <arend.vanspriel@...adcom.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>, yi1.li@...ux.intel.com,
        atull@...nsource.altera.com,
        Moritz Fischer <moritz.fischer@...us.com>, pmladek@...e.com,
        Johannes Berg <johannes.berg@...el.com>,
        emmanuel.grumbach@...el.com, luciano.coelho@...el.com,
        Kalle Valo <kvalo@...eaurora.org>, luto@...nel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Kees Cook <keescook@...omium.org>,
        "AKASHI, Takahiro" <takahiro.akashi@...aro.org>,
        David Howells <dhowells@...hat.com>, pjones@...hat.com,
        Hans de Goede <hdegoede@...hat.com>, alan@...ux.intel.com,
        tytso@....edu, lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] firmware: remove request_firmware_into_buf()

On Mon 26 Jun 23:52 PDT 2017, Greg Kroah-Hartman wrote:

> On Mon, Jun 26, 2017 at 01:22:41PM -0700, Bjorn Andersson wrote:
> > On Fri, Jun 23, 2017 at 9:03 AM, Greg Kroah-Hartman
> > <gregkh@...uxfoundation.org> wrote:
> > > As Luis pointed out, there are no in-kernel users of
> > > request_firmware_into_buf(), so remove it, and the now unused internal
> > > flag, which simplifies the logic around buffer handling a bit.
> > >
> > 
> > This API was implemented to reduce the memory pressure during firmware
> > load in the Qualcomm remoteprocs, but it wasn't available when I
> > upstreamed that code and I apparently forgot to send out the patch
> > moving us over to use this API...
> > 
> > Especially when loading the Qualcomm modem we have a couple of files
> > that we request_firmware() that are 10-15MB in size, so this
> > functionality is definitely wanted.
> > 
> > 
> > As we are calling release_firmware() immediately following the
> > request_firmware() I did attempt to just call
> > kernel_read_file_from_path() directly, but as I don't have access to
> > the fw_path[] this becomes inconsistent, so I would like to keep
> > request_firmware_into_buf().
> 
> Why would we keep it if there is no in-tree user for it?  If you want it
> sometime in the future, great, we can revert the deletion then, but
> keeping it around for nothing isn't ok, you know that :)
> 

Of course I know that :)

I did put a patch in the tubes for this yesterday [1], it's late for
v4.13, but I would be happy to see the API stay and we would have a user
in v4.14 (and tick this off Qualcomm's "required" list).

[1] https://lkml.org/lkml/2017/6/26/693

Regards,
Bjorn