[tip:perf/urgent] perf/bpf: Convert perf_event_array to use struct file
From: tip-bot for Alexei Starovoitov
Date: Fri Jan 29 2016 - 06:30:06 EST
Commit-ID: e03e7ee34fdd1c3ef494949a75cb8c61c7265fa9
Gitweb: http://git.kernel.org/tip/e03e7ee34fdd1c3ef494949a75cb8c61c7265fa9
Author: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>
AuthorDate: Mon, 25 Jan 2016 20:59:49 -0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 29 Jan 2016 08:35:25 +0100
perf/bpf: Convert perf_event_array to use struct file
Robustify refcounting.
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: vince@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20160126045947.GA40151@xxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/perf_event.h | 4 ++--
kernel/bpf/arraymap.c | 21 +++++++++++----------
kernel/events/core.c | 21 ++++++++++-----------
kernel/trace/bpf_trace.c | 14 ++++++++++----
4 files changed, 33 insertions(+), 27 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 6612732..4f90434 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -729,7 +729,7 @@ extern int perf_event_init_task(struct task_struct *child);
extern void perf_event_exit_task(struct task_struct *child);
extern void perf_event_free_task(struct task_struct *task);
extern void perf_event_delayed_put(struct task_struct *task);
-extern struct perf_event *perf_event_get(unsigned int fd);
+extern struct file *perf_event_get(unsigned int fd);
extern const struct perf_event_attr *perf_event_attrs(struct perf_event *event);
extern void perf_event_print_debug(void);
extern void perf_pmu_disable(struct pmu *pmu);
@@ -1070,7 +1070,7 @@ static inline int perf_event_init_task(struct task_struct *child) { return 0; }
static inline void perf_event_exit_task(struct task_struct *child) { }
static inline void perf_event_free_task(struct task_struct *task) { }
static inline void perf_event_delayed_put(struct task_struct *task) { }
-static inline struct perf_event *perf_event_get(unsigned int fd) { return ERR_PTR(-EINVAL); }
+static inline struct file *perf_event_get(unsigned int fd) { return ERR_PTR(-EINVAL); }
static inline const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
{
return ERR_PTR(-EINVAL);
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index b0799bc..89ebbc4 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -291,10 +291,13 @@ static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)
{
struct perf_event *event;
const struct perf_event_attr *attr;
+ struct file *file;
- event = perf_event_get(fd);
- if (IS_ERR(event))
- return event;
+ file = perf_event_get(fd);
+ if (IS_ERR(file))
+ return file;
+
+ event = file->private_data;
attr = perf_event_attrs(event);
if (IS_ERR(attr))
@@ -304,24 +307,22 @@ static void *perf_event_fd_array_get_ptr(struct bpf_map *map, int fd)
goto err;
if (attr->type == PERF_TYPE_RAW)
- return event;
+ return file;
if (attr->type == PERF_TYPE_HARDWARE)
- return event;
+ return file;
if (attr->type == PERF_TYPE_SOFTWARE &&
attr->config == PERF_COUNT_SW_BPF_OUTPUT)
- return event;
+ return file;
err:
- perf_event_release_kernel(event);
+ fput(file);
return ERR_PTR(-EINVAL);
}
static void perf_event_fd_array_put_ptr(void *ptr)
{
- struct perf_event *event = ptr;
-
- perf_event_release_kernel(event);
+ fput((struct file *)ptr);
}
static const struct bpf_map_ops perf_event_array_ops = {
diff --git a/kernel/events/core.c b/kernel/events/core.c
index fe97f95..eb44730 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8916,21 +8916,20 @@ void perf_event_delayed_put(struct task_struct *task)
WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
}
-struct perf_event *perf_event_get(unsigned int fd)
+struct file *perf_event_get(unsigned int fd)
{
- int err;
- struct fd f;
- struct perf_event *event;
+ struct file *file;
- err = perf_fget_light(fd, &f);
- if (err)
- return ERR_PTR(err);
+ file = fget_raw(fd);
+ if (!file)
+ return ERR_PTR(-EBADF);
- event = f.file->private_data;
- atomic_long_inc(&event->refcount);
- fdput(f);
+ if (file->f_op != &perf_fops) {
+ fput(file);
+ return ERR_PTR(-EBADF);
+ }
- return event;
+ return file;
}
const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 45dd798..326a75e 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -191,14 +191,17 @@ static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5)
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
struct bpf_array *array = container_of(map, struct bpf_array, map);
struct perf_event *event;
+ struct file *file;
if (unlikely(index >= array->map.max_entries))
return -E2BIG;
- event = (struct perf_event *)array->ptrs[index];
- if (!event)
+ file = (struct file *)array->ptrs[index];
+ if (unlikely(!file))
return -ENOENT;
+ event = file->private_data;
+
/* make sure event is local and doesn't have pmu::count */
if (event->oncpu != smp_processor_id() ||
event->pmu->count)
@@ -228,6 +231,7 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 index, u64 r4, u64 size)
void *data = (void *) (long) r4;
struct perf_sample_data sample_data;
struct perf_event *event;
+ struct file *file;
struct perf_raw_record raw = {
.size = size,
.data = data,
@@ -236,10 +240,12 @@ static u64 bpf_perf_event_output(u64 r1, u64 r2, u64 index, u64 r4, u64 size)
if (unlikely(index >= array->map.max_entries))
return -E2BIG;
- event = (struct perf_event *)array->ptrs[index];
- if (unlikely(!event))
+ file = (struct file *)array->ptrs[index];
+ if (unlikely(!file))
return -ENOENT;
+ event = file->private_data;
+
if (unlikely(event->attr.type != PERF_TYPE_SOFTWARE ||
event->attr.config != PERF_COUNT_SW_BPF_OUTPUT))
return -EINVAL;