From: Saravana Kannan <saravanak@google.com>
To: Michael Walle <michael@walle.cc>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Roy Zang <roy.zang@nxp.com>, PCI <linux-pci@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Minghuan Lian <minghuan.Lian@nxp.com>,
Mingkai Hu <mingkai.hu@nxp.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Bjorn Helgaas <bhelgaas@google.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] PCI: dwc: layerscape: convert to builtin_platform_driver()
Date: Mon, 25 Jan 2021 14:41:46 -0800 [thread overview]
Message-ID: <CAGETcx8FO+YSM0jwCnDdnvE3NCdjZ=1FSmAZpyaOEOvCgd4SXw@mail.gmail.com> (raw)
In-Reply-To: <a24391e62b107040435766fff52bdd31@walle.cc>
On Mon, Jan 25, 2021 at 11:49 AM Michael Walle <michael@walle.cc> wrote:
>
> Am 2021-01-21 12:01, schrieb Geert Uytterhoeven:
> > Hi Saravana,
> >
> > On Thu, Jan 21, 2021 at 1:05 AM Saravana Kannan <saravanak@google.com>
> > wrote:
> >> On Wed, Jan 20, 2021 at 3:53 PM Michael Walle <michael@walle.cc>
> >> wrote:
> >> > Am 2021-01-20 20:47, schrieb Saravana Kannan:
> >> > > On Wed, Jan 20, 2021 at 11:28 AM Michael Walle <michael@walle.cc>
> >> > > wrote:
> >> > >>
> >> > >> [RESEND, fat-fingered the buttons of my mail client and converted
> >> > >> all CCs to BCCs :(]
> >> > >>
> >> > >> Am 2021-01-20 20:02, schrieb Saravana Kannan:
> >> > >> > On Wed, Jan 20, 2021 at 6:24 AM Rob Herring <robh@kernel.org> wrote:
> >> > >> >>
> >> > >> >> On Wed, Jan 20, 2021 at 4:53 AM Michael Walle <michael@walle.cc>
> >> > >> >> wrote:
> >> > >> >> >
> >> > >> >> > fw_devlink will defer the probe until all suppliers are ready. We can't
> >> > >> >> > use builtin_platform_driver_probe() because it doesn't retry after probe
> >> > >> >> > deferral. Convert it to builtin_platform_driver().
> >> > >> >>
> >> > >> >> If builtin_platform_driver_probe() doesn't work with fw_devlink, then
> >> > >> >> shouldn't it be fixed or removed?
> >> > >> >
> >> > >> > I was actually thinking about this too. The problem with fixing
> >> > >> > builtin_platform_driver_probe() to behave like
> >> > >> > builtin_platform_driver() is that these probe functions could be
> >> > >> > marked with __init. But there are also only 20 instances of
> >> > >> > builtin_platform_driver_probe() in the kernel:
> >> > >> > $ git grep ^builtin_platform_driver_probe | wc -l
> >> > >> > 20
> >> > >> >
> >> > >> > So it might be easier to just fix them to not use
> >> > >> > builtin_platform_driver_probe().
> >> > >> >
> >> > >> > Michael,
> >> > >> >
> >> > >> > Any chance you'd be willing to help me by converting all these to
> >> > >> > builtin_platform_driver() and delete builtin_platform_driver_probe()?
> >> > >>
> >> > >> If it just moving the probe function to the _driver struct and
> >> > >> remove the __init annotations. I could look into that.
> >> > >
> >> > > Yup. That's pretty much it AFAICT.
> >> > >
> >> > > builtin_platform_driver_probe() also makes sure the driver doesn't ask
> >> > > for async probe, etc. But I doubt anyone is actually setting async
> >> > > flags and still using builtin_platform_driver_probe().
> >> >
> >> > Hasn't module_platform_driver_probe() the same problem? And there
> >> > are ~80 drivers which uses that.
> >>
> >> Yeah. The biggest problem with all of these is the __init markers.
> >> Maybe some familiar with coccinelle can help?
> >
> > And dropping them will increase memory usage.
>
> Although I do have the changes for the builtin_platform_driver_probe()
> ready, I don't think it makes much sense to send these unless we agree
> on the increased memory footprint. While there are just a few
> builtin_platform_driver_probe() and memory increase _might_ be
> negligible, there are many more module_platform_driver_probe().
While it's good to drop code that'll not be used past kernel init, the
module_platform_driver_probe() is going even more extreme. It doesn't
even allow deferred probe (well before kernel init is done). I don't
think that behavior is right and that's why we should delete it. Also,
I doubt if any of these probe functions even take up 4KB of memory.
-Saravana
next prev parent reply other threads:[~2021-01-25 22:44 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 10:52 [PATCH] PCI: dwc: layerscape: convert to builtin_platform_driver() Michael Walle
2021-01-20 14:23 ` Rob Herring
2021-01-20 14:34 ` Michael Walle
2021-01-20 15:50 ` Greg Kroah-Hartman
2021-01-20 19:02 ` Saravana Kannan
2021-01-20 19:25 ` Michael Walle
2021-01-20 19:28 ` Michael Walle
2021-01-20 19:47 ` Saravana Kannan
2021-01-20 19:47 ` Saravana Kannan
2021-01-20 23:53 ` Michael Walle
2021-01-20 23:58 ` Saravana Kannan
2021-01-21 11:01 ` Geert Uytterhoeven
2021-01-25 19:49 ` Michael Walle
2021-01-25 22:41 ` Saravana Kannan [this message]
2021-01-26 8:50 ` Geert Uytterhoeven
2021-01-27 0:44 ` Saravana Kannan
2021-01-27 7:43 ` Geert Uytterhoeven
2021-01-27 16:41 ` Saravana Kannan
2021-01-27 16:56 ` Geert Uytterhoeven
2021-01-27 17:10 ` Saravana Kannan
2021-01-28 9:25 ` Geert Uytterhoeven
2021-01-28 10:35 ` Tony Lindgren
2021-01-28 10:00 ` Tony Lindgren
2021-01-25 16:50 ` Lorenzo Pieralisi
2021-01-25 18:58 ` Saravana Kannan
2021-01-25 19:44 ` Michael Walle
2021-01-26 10:02 ` Lorenzo Pieralisi
2021-01-26 10:39 ` Michael Walle
2021-01-26 10:56 ` Geert Uytterhoeven
2021-01-26 10:55 ` Lorenzo Pieralisi
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