Re: [PATCH V2 RESEND] firmware: simplify defining and handling FW_OPT_FALLBACK

[RafaÅ MiÅecki]

On 02/21/2017 06:10 PM, Luis R. Rodriguez wrote:
> On Wed, Feb 15, 2017 at 04:05:13PM +0100, RafaÅ MiÅecki wrote:
> > From: RafaÅ MiÅecki <rafal@xxxxxxxxxx>
> >
> > I found handling of FW_OPT_FALLBACK a bit complex. It was defined using
> > another option and their values were dependent on kernel config.
> >
> > It was also non-trivial to follow the code. Some callers were using
> > FW_OPT_FALLBACK which was confusing since the _request_firmware function
> > was always checking for FW_OPT_USERHELPER (the same bit in a relevant
> > configuration).
> >
> > With this patch FW_OPT_USERHELPER gets its own bit and is explicitly
> > checked in the _request_firmware which hopefully makes code easier to
> > understand.
> >
> > Signed-off-by: RafaÅ MiÅecki <rafal@xxxxxxxxxx>
> > ---
> > V2: s/config_enabled/IS_ENABLED/ to compile since c0a0aba8e47 ("kconfig.h: remove config_enabled() macro")
> >
> > RESEND: I was suggested to resend this patch (thanks Greg!)
> >
> > Ming/Luis/Greg: could someone accept this patch, please? I hope this trivial
> > cleanup isn't too big deal.
> > ---
> >  drivers/base/firmware_class.c | 12 ++++++------
> >  1 file changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c
> > index ac350c518e0c..d05be1732c8b 100644
> > --- a/drivers/base/firmware_class.c
> > +++ b/drivers/base/firmware_class.c
> > @@ -190,13 +190,9 @@ static int __fw_state_check(struct fw_state *fw_st, enum fw_status status)
> >  #else
> >  #define FW_OPT_USERHELPER	0
> >  #endif
> > -#ifdef CONFIG_FW_LOADER_USER_HELPER_FALLBACK
> > -#define FW_OPT_FALLBACK		FW_OPT_USERHELPER
> > -#else
> > -#define FW_OPT_FALLBACK		0
> > -#endif
> >  #define FW_OPT_NO_WARN	(1U << 3)
> >  #define FW_OPT_NOCACHE	(1U << 4)
> > +#define FW_OPT_FALLBACK	(1U << 5)
> >
> >  struct firmware_cache {
> >  	/* firmware_buf instance will be added into the below list */
> > @@ -1210,8 +1206,12 @@ _request_firmware(const struct firmware **firmware_p, const char *name,
> >  			dev_warn(device,
> >  				 "Direct firmware load for %s failed with error %d\n",
> >  				 name, ret);
> > -		if (opt_flags & FW_OPT_USERHELPER) {
> > +		if (IS_ENABLED(CONFIG_FW_LOADER_USER_HELPER_FALLBACK) &&
> > +		    opt_flags & FW_OPT_FALLBACK) {
> >  			dev_warn(device, "Falling back to user helper\n");
> > +			opt_flags |= FW_OPT_USERHELPER;
> > +		}
> > +		if (opt_flags & FW_OPT_USERHELPER) {
> >  			ret = fw_load_from_user_helper(fw, name, device,
> >  						       opt_flags, timeout);
>
> I've given this some thought and while at first glance it seems like an
> improvement but it deviates from the traditional way we fold out features in
> Linux. Instead let's just wrap properly the entire functionality into wrappers
> which will no-op for when the fallback mechanism is disabled. That dev_warn()
> for example can just be moved to the call fw_load_from_user_helper() and when
> we disable the feature it will be no-op. Ultimately I'd like to shove the
> entire fallback mechanism to its own file.

I don't understand this part: "dev_warn() for example can just be moved to the
call fw_load_from_user_helper()".

Did you mean moving dev_warn into fw_load_from_user_helper function? Should I
move (opt_flags & FW_OPT_USERHELPER) condition there as well?