Re: [PATCH v7 02/16] arm64: Use update{,_tsk}_thread_flag()

[Will Deacon <will.deacon@arm.com>]

Hi Dave,

On Wed, May 09, 2018 at 05:12:51PM +0100, Dave Martin wrote:
> This patch uses the new update_thread_flag() helpers to simplify a
> couple of if () set; else clear; constructs.
> 
> No functional change.
> 
> Signed-off-by: Dave Martin <Dave.Martin@arm.com>
> Acked-by: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> ---
>  arch/arm64/kernel/fpsimd.c | 19 +++++++------------
>  1 file changed, 7 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
> index 87a3536..0c4e7e0 100644
> --- a/arch/arm64/kernel/fpsimd.c
> +++ b/arch/arm64/kernel/fpsimd.c
> @@ -618,10 +618,8 @@ int sve_set_vector_length(struct task_struct *task,
>  	task->thread.sve_vl = vl;
>  
>  out:
> -	if (flags & PR_SVE_VL_INHERIT)
> -		set_tsk_thread_flag(task, TIF_SVE_VL_INHERIT);
> -	else
> -		clear_tsk_thread_flag(task, TIF_SVE_VL_INHERIT);
> +	update_tsk_thread_flag(task, TIF_SVE_VL_INHERIT,
> +			       flags & PR_SVE_VL_INHERIT);
>  
>  	return 0;
>  }
> @@ -902,7 +900,7 @@ void fpsimd_thread_switch(struct task_struct *next)
>  	if (current->mm)
>  		task_fpsimd_save();
>  
> -	if (next->mm) {
> +	if (next->mm)
>  		/*
>  		 * If we are switching to a task whose most recent userland
>  		 * FPSIMD state is already in the registers of *this* cpu,
> @@ -910,13 +908,10 @@ void fpsimd_thread_switch(struct task_struct *next)
>  		 * the TIF_FOREIGN_FPSTATE flag so the state will be loaded
>  		 * upon the next return to userland.
>  		 */
> -		if (__this_cpu_read(fpsimd_last_state.st) ==
> -			&next->thread.uw.fpsimd_state
> -		    && next->thread.fpsimd_cpu == smp_processor_id())
> -			clear_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE);
> -		else
> -			set_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE);
> -	}
> +		update_tsk_thread_flag(next, TIF_FOREIGN_FPSTATE,
> +			__this_cpu_read(fpsimd_last_state.st) !=
> +				&next->thread.uw.fpsimd_state ||
> +			next->thread.fpsimd_cpu != smp_processor_id());

Given the multi-line comment and this multi-line call, I'd be inclined to
leave the curlies in place and then use a local bool for the complex
condition.

With that:

Acked-by: Will Deacon <will.deacon@arm.com>

Will