[PATCH 0/3] Fix some build warnings in perf/events subsystem.

[PATCH 0/3] Fix some build warnings in perf/events subsystem.

[Haocheng Xie]

I have got these warnings when building kernel with  'W=1' options:

kernel/events/core.c:6670:6: warning: no previous prototype for 'perf_pmu_snapshot_aux' [-Wmissing-prototypes]
kernel/events/core.c:143: warning: Function parameter or member 'cpu' not described in 'cpu_function_call'
kernel/events/core.c:11924: warning: Function parameter or member 'flags' not described in 'sys_perf_event_open'
kernel/events/core.c:12382: warning: Function parameter or member 'overflow_handler' not described in 'perf_event_create_kernel_counter'
kernel/events/core.c:12382: warning: Function parameter or member 'context' not described in 'perf_event_create_kernel_counter'
kernel/events/hw_breakpoint.c:461: warning: Function parameter or member 'context' not described in 'register_user_hw_breakpoint'
kernel/events/hw_breakpoint.c:560: warning: Function parameter or member 'context' not described in 'register_wide_hw_breakpoint'

The 3-patch series will fix these warnings.

Haocheng Xie (3):
  perf core:  Make local function perf_pmu_snapshot_aux() static
  perf core: Fix some kernel-doc warnings.
  perf/hw_breakpoint: Fix kernel-doc warnings in perf hw_breakpoint

 kernel/events/core.c          | 6 +++++-
 kernel/events/hw_breakpoint.c | 2 ++
 2 files changed, 7 insertions(+), 1 deletion(-)

-- 
2.9.5

[PATCH 1/3] perf core: Make local function perf_pmu_snapshot_aux() static

[Haocheng Xie]

Fixes the following W=1 kernel build warning:
  kernel/events/core.c:6670:6: warning: no previous prototype for 'perf_pmu_snapshot_aux' [-Wmissing-prototypes]

Signed-off-by: Haocheng Xie <xiehaocheng.cn@gmail.com>
---
 kernel/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 6fee4a7..0d98d6a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6667,7 +6667,7 @@ static unsigned long perf_prepare_sample_aux(struct perf_event *event,
 	return data->aux_size;
 }
 
-long perf_pmu_snapshot_aux(struct perf_buffer *rb,
+static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
 			   struct perf_event *event,
 			   struct perf_output_handle *handle,
 			   unsigned long size)
-- 
2.9.5

[PATCH 2/3] perf core: Fix some kernel-doc warnings.

[Haocheng Xie]

Fix the following W=1 kernel build warning(s):
kernel/events/core.c:143: warning: Function parameter or member 'cpu' not described in 'cpu_function_call'
kernel/events/core.c:11924: warning: Function parameter or member 'flags' not described in 'sys_perf_event_open'
kernel/events/core.c:12382: warning: Function parameter or member 'overflow_handler' not described in 'perf_event_create_kernel_counter'
kernel/events/core.c:12382: warning: Function parameter or member 'context' not described in 'perf_event_create_kernel_counter'

Signed-off-by: Haocheng Xie <xiehaocheng.cn@gmail.com>
---
 kernel/events/core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0d98d6a..7988e40 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -132,6 +132,7 @@ task_function_call(struct task_struct *p, remote_function_f func, void *info)
 
 /**
  * cpu_function_call - call a function on the cpu
+ * @cpu:	target cpu to queue this function
  * @func:	the function to be called
  * @info:	the function call argument
  *
@@ -11917,6 +11918,7 @@ __perf_event_ctx_lock_double(struct perf_event *group_leader,
  * @pid:		target pid
  * @cpu:		target cpu
  * @group_fd:		group leader event fd
+ * @flags:		perf event open flags
  */
 SYSCALL_DEFINE5(perf_event_open,
 		struct perf_event_attr __user *, attr_uptr,
@@ -12373,6 +12375,8 @@ SYSCALL_DEFINE5(perf_event_open,
  * @attr: attributes of the counter to create
  * @cpu: cpu in which the counter is bound
  * @task: task to profile (NULL for percpu)
+ * @overflow_handler: callback to trigger when we hit the event
+ * @context: context data could be used in overflow_handler callback
  */
 struct perf_event *
 perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
-- 
2.9.5

[PATCH 3/3] perf/hw_breakpoint: Fix kernel-doc warnings in perf hw_breakpoint

[Haocheng Xie]

Fix the following W=1 kernel build warning(s):

  kernel/events/hw_breakpoint.c:461: warning: Function parameter or member 'context' not described in 'register_user_hw_breakpoint'
  kernel/events/hw_breakpoint.c:560: warning: Function parameter or member 'context' not described in 'register_wide_hw_breakpoint'

Signed-off-by: Haocheng Xie <xiehaocheng.cn@gmail.com>
---
 kernel/events/hw_breakpoint.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c
index b48d703..8359734 100644
--- a/kernel/events/hw_breakpoint.c
+++ b/kernel/events/hw_breakpoint.c
@@ -451,6 +451,7 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
  * register_user_hw_breakpoint - register a hardware breakpoint for user space
  * @attr: breakpoint attributes
  * @triggered: callback to trigger when we hit the breakpoint
+ * @context: context data could be used in the triggered callback
  * @tsk: pointer to 'task_struct' of the process to which the address belongs
  */
 struct perf_event *
@@ -550,6 +551,7 @@ EXPORT_SYMBOL_GPL(unregister_hw_breakpoint);
  * register_wide_hw_breakpoint - register a wide breakpoint in the kernel
  * @attr: breakpoint attributes
  * @triggered: callback to trigger when we hit the breakpoint
+ * @context: context data could be used in the triggered callback
  *
  * @return a set of per_cpu pointers to perf events
  */
-- 
2.9.5

Re: [PATCH 1/3] perf core: Make local function perf_pmu_snapshot_aux() static

[Peter Zijlstra]

On Wed, May 26, 2021 at 07:52:18PM +0800, Haocheng Xie wrote:
> Fixes the following W=1 kernel build warning:
>   kernel/events/core.c:6670:6: warning: no previous prototype for 'perf_pmu_snapshot_aux' [-Wmissing-prototypes]
> 
> Signed-off-by: Haocheng Xie <xiehaocheng.cn@gmail.com>
> ---
>  kernel/events/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 6fee4a7..0d98d6a 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -6667,7 +6667,7 @@ static unsigned long perf_prepare_sample_aux(struct perf_event *event,
>  	return data->aux_size;
>  }
>  
> -long perf_pmu_snapshot_aux(struct perf_buffer *rb,
> +static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
>  			   struct perf_event *event,
>  			   struct perf_output_handle *handle,
>  			   unsigned long size)

Your $subject is broken (superfluous whitespace) and you've wrecked
alignment of the arguments in the core.

Re: [PATCH 1/3] perf core: Make local function perf_pmu_snapshot_aux() static

[Haocheng Xie]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=y, Size: 1342 bytes --]

* Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Wed, May 26, 2021 at 07:52:18PM +0800, Haocheng Xie wrote:
> > Fixes the following W=1 kernel build warning:
> >   kernel/events/core.c:6670:6: warning: no previous prototype for 'perf_pmu_snapshot_aux' [-Wmissing-prototypes]
> >
> > Signed-off-by: Haocheng Xie <xiehaocheng.cn@gmail.com>
> > ---
> >  kernel/events/core.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/events/core.c b/kernel/events/core.c
> > index 6fee4a7..0d98d6a 100644
> > --- a/kernel/events/core.c
> > +++ b/kernel/events/core.c
> > @@ -6667,7 +6667,7 @@ static unsigned long perf_prepare_sample_aux(struct perf_event *event,
> >       return data->aux_size;
> >  }
> >
> > -long perf_pmu_snapshot_aux(struct perf_buffer *rb,
> > +static long perf_pmu_snapshot_aux(struct perf_buffer *rb,
> >                          struct perf_event *event,
> >                          struct perf_output_handle *handle,
> >                          unsigned long size)
>
> Your $subject is broken (superfluous whitespace) and you've wrecked
> alignment of the arguments in the core.

Hi, Peter:
  Sorry for bothering you for these simple mistakes.
  I will optimize my patch series and send a "v2" version after that.

Thanks,

Haocheng Xie