diff options
| author |   Song Liu <songliubraving@fb.com> | 2020-06-29 23:28:43 -0700 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2020-07-01 08:22:08 -0700 |
| commit | d141b8bc5773cbbaf5b8530f08f94fc10fff9e8c (patch) | |
| tree | b38dafc5c0d9bd82ed208d027c505ea034f764d8 | |
| parent | bpf: Remove redundant synchronize_rcu. (diff) | |
| download | linux-dev-d141b8bc5773cbbaf5b8530f08f94fc10fff9e8c.tar.xz linux-dev-d141b8bc5773cbbaf5b8530f08f94fc10fff9e8c.zip | |
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
| -rw-r--r-- | include/linux/perf_event.h | 2 | ||||
| -rw-r--r-- | kernel/events/callchain.c | 13 |
2 files changed, 8 insertions, 7 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index b4bb32082342..00ab5efa3833 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1244,6 +1244,8 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user, extern struct perf_callchain_entry *perf_callchain(struct perf_event *event, struct pt_regs *regs); extern int get_callchain_buffers(int max_stack); extern void put_callchain_buffers(void); +extern struct perf_callchain_entry *get_callchain_entry(int *rctx); +extern void put_callchain_entry(int rctx); extern int sysctl_perf_event_max_stack; extern int sysctl_perf_event_max_contexts_per_stack; 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; |