Re: [RESEND PATCH v5 2/4] perf/bpf: Remove unneeded uses_default_overflow_handler.

[Andrii Nakryiko]

On Wed, Feb 14, 2024 at 9:40 AM Kyle Huey <me@xxxxxxxxxxxx> wrote:
>
> Now that struct perf_event's orig_overflow_handler is gone, there's no need
> for the functions and macros to support looking past overflow_handler to
> orig_overflow_handler.
>
> This patch is solely a refactoring and results in no behavior change.
>
> Signed-off-by: Kyle Huey <khuey@xxxxxxxxxxxx>
> Acked-by: Will Deacon <will@xxxxxxxxxx>
> Acked-by: Song Liu <song@xxxxxxxxxx>
> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---

oh, never mind what I said in the first patch about this :)

Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>

>  arch/arm/kernel/hw_breakpoint.c   |  8 ++++----
>  arch/arm64/kernel/hw_breakpoint.c |  4 ++--
>  include/linux/perf_event.h        | 16 ++--------------
>  3 files changed, 8 insertions(+), 20 deletions(-)
>
> diff --git a/arch/arm/kernel/hw_breakpoint.c b/arch/arm/kernel/hw_breakpoint.c
> index dc0fb7a81371..054e9199f30d 100644
> --- a/arch/arm/kernel/hw_breakpoint.c
> +++ b/arch/arm/kernel/hw_breakpoint.c
> @@ -626,7 +626,7 @@ int hw_breakpoint_arch_parse(struct perf_event *bp,
>         hw->address &= ~alignment_mask;
>         hw->ctrl.len <<= offset;
>
> -       if (uses_default_overflow_handler(bp)) {
> +       if (is_default_overflow_handler(bp)) {
>                 /*
>                  * Mismatch breakpoints are required for single-stepping
>                  * breakpoints.
> @@ -798,7 +798,7 @@ static void watchpoint_handler(unsigned long addr, unsigned int fsr,
>                  * Otherwise, insert a temporary mismatch breakpoint so that
>                  * we can single-step over the watchpoint trigger.
>                  */
> -               if (!uses_default_overflow_handler(wp))
> +               if (!is_default_overflow_handler(wp))
>                         continue;
>  step:
>                 enable_single_step(wp, instruction_pointer(regs));
> @@ -811,7 +811,7 @@ static void watchpoint_handler(unsigned long addr, unsigned int fsr,
>                 info->trigger = addr;
>                 pr_debug("watchpoint fired: address = 0x%x\n", info->trigger);
>                 perf_bp_event(wp, regs);
> -               if (uses_default_overflow_handler(wp))
> +               if (is_default_overflow_handler(wp))
>                         enable_single_step(wp, instruction_pointer(regs));
>         }
>
> @@ -886,7 +886,7 @@ static void breakpoint_handler(unsigned long unknown, struct pt_regs *regs)
>                         info->trigger = addr;
>                         pr_debug("breakpoint fired: address = 0x%x\n", addr);
>                         perf_bp_event(bp, regs);
> -                       if (uses_default_overflow_handler(bp))
> +                       if (is_default_overflow_handler(bp))
>                                 enable_single_step(bp, addr);
>                         goto unlock;
>                 }
> diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
> index 35225632d70a..db2a1861bb97 100644
> --- a/arch/arm64/kernel/hw_breakpoint.c
> +++ b/arch/arm64/kernel/hw_breakpoint.c
> @@ -654,7 +654,7 @@ static int breakpoint_handler(unsigned long unused, unsigned long esr,
>                 perf_bp_event(bp, regs);
>
>                 /* Do we need to handle the stepping? */
> -               if (uses_default_overflow_handler(bp))
> +               if (is_default_overflow_handler(bp))
>                         step = 1;
>  unlock:
>                 rcu_read_unlock();
> @@ -733,7 +733,7 @@ static u64 get_distance_from_watchpoint(unsigned long addr, u64 val,
>  static int watchpoint_report(struct perf_event *wp, unsigned long addr,
>                              struct pt_regs *regs)
>  {
> -       int step = uses_default_overflow_handler(wp);
> +       int step = is_default_overflow_handler(wp);
>         struct arch_hw_breakpoint *info = counter_arch_bp(wp);
>
>         info->trigger = addr;
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index c7f54fd74d89..c8bd5bb6610c 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -1341,8 +1341,9 @@ extern int perf_event_output(struct perf_event *event,
>                              struct pt_regs *regs);
>
>  static inline bool
> -__is_default_overflow_handler(perf_overflow_handler_t overflow_handler)
> +is_default_overflow_handler(struct perf_event *event)
>  {
> +       perf_overflow_handler_t overflow_handler = event->overflow_handler;
>         if (likely(overflow_handler == perf_event_output_forward))
>                 return true;
>         if (unlikely(overflow_handler == perf_event_output_backward))
> @@ -1350,19 +1351,6 @@ __is_default_overflow_handler(perf_overflow_handler_t overflow_handler)
>         return false;
>  }
>
> -#define is_default_overflow_handler(event) \
> -       __is_default_overflow_handler((event)->overflow_handler)
> -
> -#ifdef CONFIG_BPF_SYSCALL
> -static inline bool uses_default_overflow_handler(struct perf_event *event)
> -{
> -       return is_default_overflow_handler(event);
> -}
> -#else
> -#define uses_default_overflow_handler(event) \
> -       is_default_overflow_handler(event)
> -#endif
> -
>  extern void
>  perf_event_header__init_id(struct perf_event_header *header,
>                            struct perf_sample_data *data,
> --
> 2.34.1
>