linux-kernel - Re: [PATCH] LoongArch: Make compute_return

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Message-ID: <CAAhV-H5oaCnRyi0xpzzoUs-VemuQtSEStHHzerZFoAQmEabCdw@mail.gmail.com>
Date:   Thu, 23 Jun 2022 17:26:35 +0800
From:   Huacai Chen <chenhuacai@...nel.org>
To:     Tiezhu Yang <yangtiezhu@...ngson.cn>
Cc:     WANG Xuerui <kernel@...0n.name>,
        Xuefeng Li <lixuefeng@...ngson.cn>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] LoongArch: Make compute_return_era() return void

Hi, Tiezhu,

On Sat, Jun 18, 2022 at 4:39 PM Tiezhu Yang <yangtiezhu@...ngson.cn> wrote:
>
> compute_return_era() always returns 0, make it return void,
> and then no need to check its return value for its callers.
>
> Signed-off-by: Tiezhu Yang <yangtiezhu@...ngson.cn>
> ---
>  arch/loongarch/include/asm/branch.h | 3 +--
>  arch/loongarch/kernel/traps.c       | 3 +--
>  2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/arch/loongarch/include/asm/branch.h b/arch/loongarch/include/asm/branch.h
> index 3f33c89..9a133e4 100644
> --- a/arch/loongarch/include/asm/branch.h
> +++ b/arch/loongarch/include/asm/branch.h
> @@ -12,10 +12,9 @@ static inline unsigned long exception_era(struct pt_regs *regs)
>         return regs->csr_era;
>  }
>
> -static inline int compute_return_era(struct pt_regs *regs)
> +static inline void compute_return_era(struct pt_regs *regs)
>  {
>         regs->csr_era += 4;
> -       return 0;
>  }
>
>  #endif /* _ASM_BRANCH_H */
> diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c
> index e4060f8..1bf58c6 100644
> --- a/arch/loongarch/kernel/traps.c
> +++ b/arch/loongarch/kernel/traps.c
> @@ -475,8 +475,7 @@ asmlinkage void noinstr do_ri(struct pt_regs *regs)
>
>         die_if_kernel("Reserved instruction in kernel code", regs);
>
> -       if (unlikely(compute_return_era(regs) < 0))
> -               goto out;
> +       compute_return_era(regs);
Maybe it is better to simply remove the compute_return_era() function?

Huacai
>
>         if (unlikely(get_user(opcode, era) < 0)) {
>                 status = SIGSEGV;
> --
> 2.1.0
>