Commit c464c76e authored by Yan, Zheng's avatar Yan, Zheng Committed by Ingo Molnar
Browse files

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: default avatarYan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1395133004-23205-1-git-send-email-zheng.z.yan@intel.com


Cc: eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar's avatarIngo Molnar <mingo@kernel.org>
parent 1111b680
......@@ -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;
......
......@@ -39,6 +39,7 @@
#include <linux/hw_breakpoint.h>
#include <linux/mm_types.h>
#include <linux/cgroup.h>
#include <linux/module.h>
#include "internal.h"
......@@ -3229,6 +3230,9 @@ static void __free_event(struct perf_event *event)
if (event->ctx)
put_ctx(event->ctx);
if (event->pmu)
module_put(event->pmu->module);
call_rcu(&event->rcu_head, free_event_rcu);
}
static void free_event(struct perf_event *event)
......@@ -6551,6 +6555,7 @@ int perf_pmu_register(struct pmu *pmu, const char *name, int type)
free_percpu(pmu->pmu_disable_count);
goto unlock;
}
EXPORT_SYMBOL_GPL(perf_pmu_register);
void perf_pmu_unregister(struct pmu *pmu)
{
......@@ -6572,6 +6577,7 @@ void perf_pmu_unregister(struct pmu *pmu)
put_device(pmu->dev);
free_pmu_context(pmu);
}
EXPORT_SYMBOL_GPL(perf_pmu_unregister);
struct pmu *perf_init_event(struct perf_event *event)
{
......@@ -6585,6 +6591,10 @@ struct pmu *perf_init_event(struct perf_event *event)
pmu = idr_find(&pmu_idr, event->attr.type);
rcu_read_unlock();
if (pmu) {
if (!try_module_get(pmu->module)) {
pmu = ERR_PTR(-ENODEV);
goto unlock;
}
event->pmu = pmu;
ret = pmu->event_init(event);
if (ret)
......@@ -6593,6 +6603,10 @@ struct pmu *perf_init_event(struct perf_event *event)
}
list_for_each_entry_rcu(pmu, &pmus, entry) {
if (!try_module_get(pmu->module)) {
pmu = ERR_PTR(-ENODEV);
goto unlock;
}
event->pmu = pmu;
ret = pmu->event_init(event);
if (!ret)
......@@ -6771,6 +6785,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
err_pmu:
if (event->destroy)
event->destroy(event);
module_put(pmu->module);
err_ns:
if (event->ns)
put_pid_ns(event->ns);
......
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