[Cocci] [PATCH] compat/compat-drivers/linux-next: fb skip_vt_switch

Luis R. Rodriguez mcgrof at do-not-panic.com
Fri Mar 29 00:25:10 CET 2013

On Thu, Mar 28, 2013 at 3:29 PM, Julia Lawall <julia.lawall at lip6.fr> wrote:
> On Thu, 28 Mar 2013, Luis R. Rodriguez wrote:
>> On Thu, Mar 28, 2013 at 11:10 AM, Julia Lawall <julia.lawall at lip6.fr> wrote:
>> > On Thu, 28 Mar 2013, Luis R. Rodriguez wrote:
>> >>
>> >> Thanks Julia! I'll be sure to try to add this to compat-drivers if the
>> >> upstream fb patch is not accepted. If it is accepted we would not need
>> >> this at all!
>> >>
>> >> > Then I guess there would be a similar rule for the false case?
>> >>
>> >> Nope, see that's the proactive strategy taken by the static inline and
>> >> hence the patch. compat would have a static inline for both cases, and
>> >> for the false case it'd be a no-op. If accepted upstream though then
>> >> we would not need any changes for this collateral evolution. However
>> >> *spotting* these collateral evolutions and giving you SmPL for them as
>> >> a proactive strategy might be good given that if these type of patches
>> >> are indeed welcomed upstream we'd then be able to address these as
>> >> secondary steps. If they are not accepted then indeed we'd use them to
>> >> backport that collateral evolution through both compat (adds the
>> >> static inlines) and compat-drivers (the SmPL).
>> >
>> > Probably I am missing something, since I haven't looked at the code in
>> > detail, bu wouldn't it be nicer to have a function call for the false
>> > case, if there is a function call for the true case?
>> Yes, and indeed we have that, its the same function call, in the
>> negative case its a no-op, in the newer kernels it wraps to modifying
>> the element as in the original code.
>> > In looking at the
>> > code, one could wonder why things are not done in a parallel way.
>> Not sure I get this.
> I looked in today's linux-next, and there seems to be only one
> initialization of this field, to true, and one test of this field.  So
> perhaps the case for setting the field to false just isn't needed.

Oh sorry now I get what you mean! I thought about this -- and yes I
decided to not add a bool false setting for the structure field given
that the assumption is this would not be something dynamic, and data
structure would be kzalloc()'d so by default they are 0.


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