perf: Allow building PMU drivers as modules

This patch adds support for building PMU driver as module. It exports
the functions perf_pmu_{register,unregister}() and adds reference tracking
for the PMU driver module.

When the PMU driver is built as a module, each active event of the PMU
holds a reference to the driver module.

Signed-off-by: Yan, Zheng <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Cc: [email protected]
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 3356abcfff18..af6dcf1d9e47 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -172,6 +172,7 @@ struct perf_event;
 struct pmu {
 	struct list_head		entry;
 
+	struct module			*module;
 	struct device			*dev;
 	const struct attribute_group	**attr_groups;
 	const char			*name;