[PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

[PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

[Zhenwen Xu]

fix warnings that caused the API change of trace_buffer_lock_reserve()
change files: kernel/trace/trace_hw_branch.c
	      kernel/trace/trace_branch.c

Signed-off-by: Zhenwen Xu <helight.xu@gmail.com>
---
 kernel/trace/trace_branch.c      |    2 +-
 kernel/trace/trace_hw_branches.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
index 7a7a9fd..216e2dd 100644
--- a/kernel/trace/trace_branch.c
+++ b/kernel/trace/trace_branch.c
@@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
 		goto out;
 
 	pc = preempt_count();
-	event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
+	event = trace_buffer_lock_reserve(tr->buffer, TRACE_BRANCH,
 					  sizeof(*entry), flags, pc);
 	if (!event)
 		goto out;
diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
index 23b6385..1cc17ca 100644
--- a/kernel/trace/trace_hw_branches.c
+++ b/kernel/trace/trace_hw_branches.c
@@ -180,7 +180,7 @@ void trace_hw_branch(u64 from, u64 to)
 	if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
 		goto out;
 
-	event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
+	event = trace_buffer_lock_reserve(tr->buffer, TRACE_HW_BRANCHES,
 					  sizeof(*entry), 0, 0);
 	if (!event)
 		goto out;
-- 
1.6.3.3

-- 
--------------------------------
http://zhwen.org - Open and Free

Re: [PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

[Li Zefan]

Zhenwen Xu wrote:
> fix warnings that caused the API change of trace_buffer_lock_reserve()
> change files: kernel/trace/trace_hw_branch.c
> 	      kernel/trace/trace_branch.c
> 

Hmm, did you really compile trace_hw_branch.c while testing
this patch?

This change is necessary too:

-	trace_buffer_unlock_commit(tr, event, 0, 0);
+	trace_buffer_unlock_commit(tr->buffer, event, 0, 0);

And use a varaible "buffer = tr->buffer" should be better.

> Signed-off-by: Zhenwen Xu <helight.xu@gmail.com>
> ---
>  kernel/trace/trace_branch.c      |    2 +-
>  kernel/trace/trace_hw_branches.c |    2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
> index 7a7a9fd..216e2dd 100644
> --- a/kernel/trace/trace_branch.c
> +++ b/kernel/trace/trace_branch.c
> @@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
>  		goto out;
>  
>  	pc = preempt_count();
> -	event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
> +	event = trace_buffer_lock_reserve(tr->buffer, TRACE_BRANCH,
>  					  sizeof(*entry), flags, pc);
>  	if (!event)
>  		goto out;
> diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
> index 23b6385..1cc17ca 100644
> --- a/kernel/trace/trace_hw_branches.c
> +++ b/kernel/trace/trace_hw_branches.c
> @@ -180,7 +180,7 @@ void trace_hw_branch(u64 from, u64 to)
>  	if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
>  		goto out;
>  
> -	event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
> +	event = trace_buffer_lock_reserve(tr->buffer, TRACE_HW_BRANCHES,
>  					  sizeof(*entry), 0, 0);
>  	if (!event)
>  		goto out;

Re: [PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

[Helight.Xu]

Li Zefan wrote:
> Zhenwen Xu wrote:
>   
>> fix warnings that caused the API change of trace_buffer_lock_reserve()
>> change files: kernel/trace/trace_hw_branch.c
>> 	      kernel/trace/trace_branch.c
>>
>>     
>
> Hmm, did you really compile trace_hw_branch.c while testing
> this patch?
>
> This change is necessary too:
>
> -	trace_buffer_unlock_commit(tr, event, 0, 0);
> +	trace_buffer_unlock_commit(tr->buffer, event, 0, 0);
>
> And use a varaible "buffer = tr->buffer" should be better.
>   
oh!   sorry for my careless!
>   
>> Signed-off-by: Zhenwen Xu <helight.xu@gmail.com>
>> ---
>>  kernel/trace/trace_branch.c      |    2 +-
>>  kernel/trace/trace_hw_branches.c |    2 +-
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
>> index 7a7a9fd..216e2dd 100644
>> --- a/kernel/trace/trace_branch.c
>> +++ b/kernel/trace/trace_branch.c
>> @@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
>>  		goto out;
>>  
>>  	pc = preempt_count();
>> -	event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
>> +	event = trace_buffer_lock_reserve(tr->buffer, TRACE_BRANCH,
>>  					  sizeof(*entry), flags, pc);
>>  	if (!event)
>>  		goto out;
>> diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
>> index 23b6385..1cc17ca 100644
>> --- a/kernel/trace/trace_hw_branches.c
>> +++ b/kernel/trace/trace_hw_branches.c
>> @@ -180,7 +180,7 @@ void trace_hw_branch(u64 from, u64 to)
>>  	if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
>>  		goto out;
>>  
>> -	event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
>> +	event = trace_buffer_lock_reserve(tr->buffer, TRACE_HW_BRANCHES,
>>  					  sizeof(*entry), 0, 0);
>>  	if (!event)
>>  		goto out;
>>     
>
>   


-- 
---------------------------------
Zhenwen Xu - Open and Free
Home Page:	http://zhwen.org

Re: [PATCH V2] fix a warning on kernel/trace/trace_branch.c and trace_hw_branches.c

[Steven Rostedt]

On Wed, 2009-10-07 at 19:40 +0800, Helight.Xu wrote:
> Li Zefan wrote:
> > Zhenwen Xu wrote:
> >   
> >> fix warnings that caused the API change of trace_buffer_lock_reserve()
> >> change files: kernel/trace/trace_hw_branch.c
> >> 	      kernel/trace/trace_branch.c
> >>
> >>     
> >
> > Hmm, did you really compile trace_hw_branch.c while testing
> > this patch?
> >
> > This change is necessary too:
> >
> > -	trace_buffer_unlock_commit(tr, event, 0, 0);
> > +	trace_buffer_unlock_commit(tr->buffer, event, 0, 0);
> >
> > And use a varaible "buffer = tr->buffer" should be better.
> >   
> oh!   sorry for my careless!
> >   
> >> Signed-off-by: Zhenwen Xu <helight.xu@gmail.com>
> >> ---
> >>  kernel/trace/trace_branch.c      |    2 +-
> >>  kernel/trace/trace_hw_branches.c |    2 +-
> >>  2 files changed, 2 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/kernel/trace/trace_branch.c b/kernel/trace/trace_branch.c
> >> index 7a7a9fd..216e2dd 100644
> >> --- a/kernel/trace/trace_branch.c
> >> +++ b/kernel/trace/trace_branch.c
> >> @@ -54,7 +54,7 @@ probe_likely_condition(struct ftrace_branch_data *f, int val, int expect)
> >>  		goto out;
> >>  
> >>  	pc = preempt_count();
> >> -	event = trace_buffer_lock_reserve(tr, TRACE_BRANCH,
> >> +	event = trace_buffer_lock_reserve(tr->buffer, TRACE_BRANCH,
> >>  					  sizeof(*entry), flags, pc);

Also, You should not pass in the buffer directly. This is because the
tr->buffer can change, and if it changes between the reserve and commit,
then you can corrupt the ring buffer.

What you want to do is:

	struct ring_buffer *buffer = tr->buffer;

	event = trace_buffer_lock_reserve(buffer, TRACE_BRANCH ...)

[...]

	ring_buffer_unlock_commit(buffer, ...)


-- Steve

> >>  	if (!event)
> >>  		goto out;
> >> diff --git a/kernel/trace/trace_hw_branches.c b/kernel/trace/trace_hw_branches.c
> >> index 23b6385..1cc17ca 100644
> >> --- a/kernel/trace/trace_hw_branches.c
> >> +++ b/kernel/trace/trace_hw_branches.c
> >> @@ -180,7 +180,7 @@ void trace_hw_branch(u64 from, u64 to)
> >>  	if (atomic_inc_return(&tr->data[cpu]->disabled) != 1)
> >>  		goto out;
> >>  
> >> -	event = trace_buffer_lock_reserve(tr, TRACE_HW_BRANCHES,
> >> +	event = trace_buffer_lock_reserve(tr->buffer, TRACE_HW_BRANCHES,
> >>  					  sizeof(*entry), 0, 0);
> >>  	if (!event)
> >>  		goto out;
> >>     
> >
> >   
> 
>