[PATCH 04/16] perf, mmap: Factor out perf_get_fd()

Jean Pihet
2014-04-07T15:10:08Z

From: Robert Richter <robert.richter@linaro.org>

This new function creates a new fd for an event. We need this later to
get a fd from a persistent event.

Signed-off-by: Robert Richter <robert.richter@linaro.org>
Signed-off-by: Robert Richter <rric@kernel.org>
Signed-off-by: Jean Pihet <jean.pihet@linaro.org>
---
kernel/events/core.c | 14 ++++++++------
kernel/events/internal.h | 1 +
2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 22ec8f0..9857475 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4206,6 +4206,11 @@ static const struct file_operations perf_fops = {
.fasync = perf_fasync,
};

+int perf_get_fd(struct perf_event *event, int f_flags)
+{
+ return anon_inode_getfd("[perf_event]", &perf_fops, event, f_flags);
+}
+
/*
* Perf event wakeup
*
@@ -7028,7 +7033,6 @@ SYSCALL_DEFINE5(perf_event_open,
struct perf_event *event, *sibling;
struct perf_event_attr attr;
struct perf_event_context *ctx;
- struct file *event_file = NULL;
struct fd group = {NULL, 0};
struct task_struct *task = NULL;
struct pmu *pmu;
@@ -7189,10 +7193,9 @@ SYSCALL_DEFINE5(perf_event_open,
goto err_context;
}

- event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
- f_flags);
- if (IS_ERR(event_file)) {
- err = PTR_ERR(event_file);
+ event_fd = perf_get_fd(event, f_flags);
+ if (event_fd < 0) {
+ err = event_fd;
goto err_context;
}

@@ -7257,7 +7260,6 @@ SYSCALL_DEFINE5(perf_event_open,
* perf_group_detach().
*/
fdput(group);
- fd_install(event_fd, event_file);
return event_fd;

err_context:
diff --git a/kernel/events/internal.h b/kernel/events/internal.h
index e9007ff..5f1f92d 100644
--- a/kernel/events/internal.h
+++ b/kernel/events/internal.h
@@ -209,5 +209,6 @@ static inline void put_event(struct perf_event *event)

extern int perf_alloc_rb(struct perf_event *event, int nr_pages, int flags);
extern void perf_free_rb(struct perf_event *event);
+extern int perf_get_fd(struct perf_event *event, int f_flags);

#endif /* _KERNEL_EVENTS_INTERNAL_H */
--
1.7.11.7