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authorSong Liu <songliubraving@fb.com>2020-06-30 09:28:43 +0300
committerAlexei Starovoitov <ast@kernel.org>2020-07-01 18:22:08 +0300
commitd141b8bc5773cbbaf5b8530f08f94fc10fff9e8c (patch)
treeb38dafc5c0d9bd82ed208d027c505ea034f764d8 /kernel
parentbba1dc0b55ac462d24ed1228ad49800c238cd6d7 (diff)
downloadlinux-d141b8bc5773cbbaf5b8530f08f94fc10fff9e8c.tar.xz
perf: Expose get/put_callchain_entry()
Sanitize and expose get/put_callchain_entry(). This would be used by bpf stack map. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200630062846.664389-2-songliubraving@fb.com
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/callchain.c13
1 files changed, 6 insertions, 7 deletions
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 334d48b16c36..c6ce894e4ce9 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -149,7 +149,7 @@ void put_callchain_buffers(void)
}
}
-static struct perf_callchain_entry *get_callchain_entry(int *rctx)
+struct perf_callchain_entry *get_callchain_entry(int *rctx)
{
int cpu;
struct callchain_cpus_entries *entries;
@@ -159,8 +159,10 @@ static struct perf_callchain_entry *get_callchain_entry(int *rctx)
return NULL;
entries = rcu_dereference(callchain_cpus_entries);
- if (!entries)
+ if (!entries) {
+ put_recursion_context(this_cpu_ptr(callchain_recursion), *rctx);
return NULL;
+ }
cpu = smp_processor_id();
@@ -168,7 +170,7 @@ static struct perf_callchain_entry *get_callchain_entry(int *rctx)
(*rctx * perf_callchain_entry__sizeof()));
}
-static void
+void
put_callchain_entry(int rctx)
{
put_recursion_context(this_cpu_ptr(callchain_recursion), rctx);
@@ -183,11 +185,8 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
int rctx;
entry = get_callchain_entry(&rctx);
- if (rctx == -1)
- return NULL;
-
if (!entry)
- goto exit_put;
+ return NULL;
ctx.entry = entry;
ctx.max_stack = max_stack;