Messages in this thread | | | From | "Bae, Chang Seok" <> | Subject | Re: [PATCH v10 04/28] x86/fpu/xstate: Modify address finders to handle both static and dynamic buffers | Date | Sun, 3 Oct 2021 22:35:41 +0000 |
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On Oct 1, 2021, at 06:15, Thomas Gleixner <tglx@linutronix.de> wrote: > On Wed, Aug 25 2021 at 08:53, Chang S. Bae wrote: > >> Have all the functions finding XSTATE address take a struct fpu * pointer >> in preparation for dynamic state buffer support. >> >> init_fpstate is a special case, which is indicated by a null pointer >> parameter to get_xsave_addr() and __raw_xsave_addr(). > > Same comment vs. subject. Prepare ...
How about: "Prepare address finders to handle dynamic features"
>> + if (fpu) >> + xsave = &fpu->state.xsave; >> + else >> + xsave = &init_fpstate.xsave; >> + >> + return xsave + xstate_comp_offsets[xfeature_nr]; > > So you have the same conditionals and the same comments vs. that NULL > pointer oddity how many times now all over the place? > > That can be completely avoided: > > Patch 1: > > -union fpregs_state init_fpstate __ro_after_init; > +static union fpregs_state init_fpstate __ro_after_init; > +struct fpu init_fpu = { .state = &init_fpstate } __ro_after_init; > > and make all users of init_fpstate access it through init_fpu. > > Patches 2..N which change arguments from fpregs_state to fpu: > > - fun(init_fpu->state); > + fun(&init_fpu); > > Patch M which adds state_mask: > > @fpu__init_system_xstate() > + init_fpu.state_mask = xfeatures_mask_all; > > Hmm?
Okay, a NULL pointer is odd and it as an argument should be avoided. Defining a separate struct fpu for the initial state can make every function expect a valid struct fpu pointer.
I think that the patch set will have such order (once [1] is dropped out) of, - patch1 (new): a cleanup patch for fpstate_init_xstate() in patch1 - patch2 (new): the above init_fpu goes into this, and - patch3-5: changes arguments to fpu, - patch6 (new): finally patch 6 to add ->state_mask and ->state_size. …
Thanks, Chang
[1] https://lore.kernel.org/lkml/20210825155413.19673-2-chang.seok.bae@intel.com/
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