Commit e649bcda authored by Josh Poimboeuf's avatar Josh Poimboeuf Committed by Peter Zijlstra
Browse files

perf: Remove get_perf_callchain() init_nr argument 



The 'init_nr' argument has double duty: it's used to initialize both the
number of contexts and the number of stack entries.  That's confusing
and the callers always pass zero anyway.  Hard code the zero.

Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarNamhyung Kim <Namhyung@kernel.org>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/r/20250820180428.259565081@kernel.org
parent f49e1be1

include/linux/perf_event.h

+1 −1
Original line number Diff line number Diff line
@@ -1719,7 +1719,7 @@ DECLARE_PER_CPU(struct perf_callchain_entry, perf_callchain_entry); 
extern void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs);

extern void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs);

extern struct perf_callchain_entry *

get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,

get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,

		   u32 max_stack, bool crosstask, bool add_mark);

extern int get_callchain_buffers(int max_stack);

extern void put_callchain_buffers(void);

kernel/bpf/stackmap.c

+2 −2
Original line number Diff line number Diff line
@@ -314,7 +314,7 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, 
	if (max_depth > sysctl_perf_event_max_stack)

		max_depth = sysctl_perf_event_max_stack;



	trace = get_perf_callchain(regs, 0, kernel, user, max_depth,

	trace = get_perf_callchain(regs, kernel, user, max_depth,

				   false, false);



	if (unlikely(!trace))
@@ -451,7 +451,7 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, 
	else if (kernel && task)

		trace = get_callchain_entry_for_task(task, max_depth);

	else

		trace = get_perf_callchain(regs, 0, kernel, user, max_depth,

		trace = get_perf_callchain(regs, kernel, user, max_depth,

					   crosstask, false);



	if (unlikely(!trace) || trace->nr < skip) {

kernel/events/callchain.c

+6 −6
Original line number Diff line number Diff line
@@ -217,7 +217,7 @@ static void fixup_uretprobe_trampoline_entries(struct perf_callchain_entry *entr 
}



struct perf_callchain_entry *

get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,

get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,

		   u32 max_stack, bool crosstask, bool add_mark)

{

	struct perf_callchain_entry *entry;
@@ -230,7 +230,7 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, 


	ctx.entry		= entry;

	ctx.max_stack		= max_stack;

	ctx.nr	      = entry->nr = init_nr;

	ctx.nr			= entry->nr = 0;

	ctx.contexts		= 0;

	ctx.contexts_maxed	= false;

kernel/events/core.c

+1 −1
Original line number Diff line number Diff line
@@ -8210,7 +8210,7 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs) 
	if (!kernel && !user)

		return &__empty_callchain;



	callchain = get_perf_callchain(regs, 0, kernel, user,

	callchain = get_perf_callchain(regs, kernel, user,

				       max_stack, crosstask, true);

	return callchain ?: &__empty_callchain;

}