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Commit e03e7ee3 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by Ingo Molnar
Browse files

perf/bpf: Convert perf_event_array to use struct file 



Robustify refcounting.

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/20160126045947.GA40151@ast-mbp.thefacebook.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 828b6f0e

include/linux/perf_event.h

+2 −2
Original line number Diff line number Diff line
@@ -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);

kernel/bpf/arraymap.c

+11 −10
Original line number Diff line number Diff line
@@ -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 = {

kernel/events/core.c

+10 −11
Original line number Diff line number Diff line
@@ -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)

kernel/trace/bpf_trace.c

+10 −4
Original line number Diff line number Diff line
@@ -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;