perf/core: add perf_get_event() to return perf_event given a struct file

A new extern function, perf_get_event(), is added to return a perf event
given a struct file. This function will be used in later patches.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index e71e99eb9a4e06602c9d421193a4e04661f667cd..eec302b61cfe2c3fca003d8ac5a7397ef5d11064 100644 (file)
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -868,6 +868,7 @@ 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 file *perf_event_get(unsigned int fd);
+extern const struct perf_event *perf_get_event(struct file *file);
 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);
@@ -1289,6 +1290,10 @@ 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 file *perf_event_get(unsigned int fd)     { return ERR_PTR(-EINVAL); }
+static inline const struct perf_event *perf_get_event(struct file *file)
+{
+       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/events/core.c b/kernel/events/core.c
index 67612ce359adc45efe1a721ced1d7c4a78aff75d..6eeab86d24babaedec4ecfce8b64e7c4b6284601 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11212,6 +11212,14 @@ struct file *perf_event_get(unsigned int fd)
        return file;
 }
 
+const struct perf_event *perf_get_event(struct file *file)
+{
+       if (file->f_op != &perf_fops)
+               return ERR_PTR(-EINVAL);
+
+       return file->private_data;
+}
+
 const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
 {
        if (!event)