Re: [PATCH v4 3/3] p54: convert to sysdata API

From: Greg KH
Date: Fri Jan 27 2017 - 09:09:03 EST


On Fri, Jan 27, 2017 at 12:25:48PM +0100, RafaÅ MiÅecki wrote:
> On 27 January 2017 at 08:47, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> > On Thu, Jan 26, 2017 at 10:50:05PM +0100, Luis R. Rodriguez wrote:
> >> On Thu, Jan 19, 2017 at 05:27:51PM +0100, Luis R. Rodriguez wrote:
> >> > On Thu, Jan 19, 2017 at 12:38:57PM +0100, Greg KH wrote:
> >> > > On Thu, Jan 12, 2017 at 07:02:44AM -0800, Luis R. Rodriguez wrote:
> >> > > > ---
> >> > > > drivers/net/wireless/intersil/p54/eeprom.c | 2 +-
> >> > > > drivers/net/wireless/intersil/p54/fwio.c | 5 +-
> >> > > > drivers/net/wireless/intersil/p54/led.c | 2 +-
> >> > > > drivers/net/wireless/intersil/p54/main.c | 2 +-
> >> > > > drivers/net/wireless/intersil/p54/p54.h | 3 +-
> >> > > > drivers/net/wireless/intersil/p54/p54pci.c | 26 ++++++----
> >> > > > drivers/net/wireless/intersil/p54/p54pci.h | 4 +-
> >> > > > drivers/net/wireless/intersil/p54/p54spi.c | 80 +++++++++++++++++++-----------
> >> > > > drivers/net/wireless/intersil/p54/p54spi.h | 2 +-
> >> > > > drivers/net/wireless/intersil/p54/p54usb.c | 18 +++----
> >> > > > drivers/net/wireless/intersil/p54/p54usb.h | 4 +-
> >> > > > drivers/net/wireless/intersil/p54/txrx.c | 2 +-
> >> > > > 12 files changed, 89 insertions(+), 61 deletions(-)
> >> > >
> >> > > why does the "new" api require more lines?
> >> >
> >> > This is a bare bones flexible API with only a few new tiny features to start
> >> > with, one of them was to enable the API do the freeing of the driver data for
> >> > you. In the kernel we have devres to help with this but devres only helps if
> >> > you would use the API call on probe. We want to support the ability to let the
> >> > API free the driver data for you even if your call is outside of probe, for this
> >> > to work we need a callback. For async calls this is rather trivial given we
> >> > already have a callback, for sync calls this means a new routine is needed.
> >> > Freeing the data for you is an option, but I decided to keep the callback
> >> > requirement even if you didn't want the free'ing to be done for you. The
> >> > addition of a callback is what accounts for the slight increase on this driver.
> >> >
> >> > I could try avoiding the callback if no freeing is needed.
> >>
> >> OK I've added a respective helper call which would map 1-1 with the
> >> old sync mechanism to enable a 1-1 change, this will be called
> >> driver_data_request_simple(), but let me know if there is a preference
> >> for something else.
> >>
> >> With this the only visible delta now is from taking advantage of new
> >> features. In p54's case this would re-organize the mess in
> >> drivers/net/wireless/intersil/p54/p54spi.c, the diff stat is a bit
> >> larger for that file just because of this but I think in this case
> >> its very much worth the small additions. In this case two routines are
> >> added for handling the work through callbacks on a sync call.
> >>
> >> 1 file changed, 38 insertions(+), 30 deletions(-)
> >
> > I agree with Linus, as well as, look, it's still bigger, so you are
> > making driver developers do more work :(
> >
> >> /* FIXME: should driver use it's own struct device? */
> >> - ret = request_firmware(&priv->firmware, "3826.arm", &priv->spi->dev);
> >> -
> >> - if (ret < 0) {
> >> - dev_err(&priv->spi->dev, "request_firmware() failed: %d", ret);
> >> + ret = driver_data_request_simple("3826.arm", &priv->spi->dev,
> >> + &priv->firmware);
> >> + if (ret < 0)
> >> return ret;
> >> - }
> >
> > Hm, a FIXME that you aren't fixing :(
> >
> > I still fail to see why this new api is worth it at all, sorry.
>
> Maybe we could try cleaning up existing firmware API and see if we
> really hit something that can't be solved in any sane way? What do you
> think?
>
> I'd love to help with that, I started with a trivial cleaning patch:
> [PATCH V2] firmware: simplify defining and handling FW_OPT_FALLBACK
> https://patchwork.kernel.org/patch/9469875/
>
> It didn't receive any real negative comments but I also have no idea
> how could pick it up for me and send in some pull request. Any
> suggestions?

Does that patch really "simplify" anything? Anyway, resend it if the
maintainer of the subsystem ignores it (you did cc: the correct people,
right?)

And yes, I always like seeing things that simplify apis, and the
firmware interface could really use that, which I thought is what Luis
was trying to do here, which is why I keep pushing back on this
patchset as it doesn't seem to be happening.

thanks,

greg k-h