linux-kernel - Re: [PATCH 04/13] tracing: Rename kvfree_rcu() to kvfree_rcu

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Message-Id: <70A3066E-3B61-4B81-B36D-69BC27DAD5E9@joelfernandes.org>
Date:   Thu, 16 Mar 2023 14:01:30 -0400
From:   Joel Fernandes <joel@...lfernandes.org>
To:     Uladzislau Rezki <urezki@...il.com>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        LKML <linux-kernel@...r.kernel.org>, RCU <rcu@...r.kernel.org>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...y.com>,
        Jens Axboe <axboe@...nel.dk>,
        Philipp Reisner <philipp.reisner@...bit.com>,
        Bryan Tan <bryantan@...are.com>,
        Eric Dumazet <edumazet@...gle.com>,
        Bob Pearson <rpearsonhpe@...il.com>,
        Ariel Levkovich <lariel@...dia.com>,
        Theodore Ts'o <tytso@....edu>, Julian Anastasov <ja@....bg>,
        Joel Fernandes <joel@...lfernandes.org>
Subject: Re: [PATCH 04/13] tracing: Rename kvfree_rcu() to kvfree_rcu_mightsleep()



> On Mar 16, 2023, at 1:58 PM, Uladzislau Rezki <urezki@...il.com> wrote:
> 
> On Wed, Mar 15, 2023 at 06:36:48PM -0400, Steven Rostedt wrote:
>> On Thu, 9 Mar 2023 14:45:21 +0100
>> Uladzislau Rezki <urezki@...il.com> wrote:
>> 
>>>> The kvfree_rcu()'s single argument name is deprecated therefore
>>>> rename it to kvfree_rcu_mightsleep() variant. The goal is explicitly
>>>> underline that it is for sleepable contexts.
>>>> 
>>>> Cc: Steven Rostedt (VMware) <rostedt@...dmis.org>
>>>> Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
>>>> 
>>> Could you please add you reviwed-by or Acked-by tags so we can bring
>>> our series with renaming for the next merge window?
>> 
>> I don't know. Perhaps we should just apply this patch and not worry about
>> sleeping and whatnot.
>> 
>> -- Steve
>> 
>> diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
>> index 04f0fdae19a1..5de945a8f61d 100644
>> --- a/kernel/trace/trace_osnoise.c
>> +++ b/kernel/trace/trace_osnoise.c
>> @@ -76,6 +76,7 @@ static unsigned long osnoise_options    = OSN_DEFAULT_OPTIONS;
>> struct osnoise_instance {
>>    struct list_head    list;
>>    struct trace_array    *tr;
>> +    struct rcu_head        rcu;
>> };
>> 
>> static struct list_head osnoise_instances;
>> @@ -159,7 +160,7 @@ static void osnoise_unregister_instance(struct trace_array *tr)
>>    if (!found)
>>        return;
>> 
>> -    kvfree_rcu(inst);
>> +    kvfree_rcu(inst, rcu);
>> }
>> 
>> /*
>> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
>> index 20d0c4a97633..ef5fafb40c76 100644
>> --- a/kernel/trace/trace_probe.c
>> +++ b/kernel/trace/trace_probe.c
>> @@ -1172,7 +1172,7 @@ int trace_probe_remove_file(struct trace_probe *tp,
>>        return -ENOENT;
>> 
>>    list_del_rcu(&link->list);
>> -    kvfree_rcu(link);
>> +    kvfree_rcu(link, rcu);
>> 
>>    if (list_empty(&tp->event->files))
>>        trace_probe_clear_flag(tp, TP_FLAG_TRACE);
>> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
>> index ef8ed3b65d05..e6037752dcf0 100644
>> --- a/kernel/trace/trace_probe.h
>> +++ b/kernel/trace/trace_probe.h
>> @@ -256,6 +256,7 @@ struct trace_probe {
>> struct event_file_link {
>>    struct trace_event_file        *file;
>>    struct list_head        list;
>> +    struct rcu_head            rcu;
>> };
>> 
>> static inline bool trace_probe_test_flag(struct trace_probe *tp,
>> 
> Anyway i do not see any problems with it
> 
> Acked-by: Uladzislau Rezki (Sony) <urezki@...il.com>

Just to clarify, we are dropping the original patch and instead taking Steves version?

If so, Steve please send a patch when you are able to and with Vlads Ack,
we can take it via the RCU tree if that is Ok with you.

Thanks,

 - Joel


> 
> --
> Uladzislau Rezki