linux-kernel - [PATCH v3 2/4] perf/bpf: Remove unneeded uses_default_overflow

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Message-Id: <20231211045543.31741-3-khuey@kylehuey.com>
Date:   Sun, 10 Dec 2023 20:55:41 -0800
From:   Kyle Huey <me@...ehuey.com>
To:     Kyle Huey <khuey@...ehuey.com>, linux-kernel@...r.kernel.org,
        Andrii Nakryiko <andrii.nakryiko@...il.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Marco Elver <elver@...gle.com>,
        Yonghong Song <yonghong.song@...ux.dev>
Cc:     Robert O'Callahan <robert@...llahan.org>,
        Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        linux-arm-kernel@...ts.infradead.org,
        linux-perf-users@...r.kernel.org, bpf@...r.kernel.org
Subject: [PATCH v3 2/4] perf/bpf: Remove unneeded uses_default_overflow_handler.

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@...ehuey.com>
---
 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 312b9f31442c..7fef6299151b 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1321,8 +1321,9 @@ 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))
@@ -1330,19 +1331,6 @@ __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