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Date:   Thu, 8 Oct 2020 03:34:16 +0000
From:   Wei Yang <richard.weiyang@gmail.com>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Wei Yang <richard.weiyang@linux.alibaba.com>, mingo@redhat.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/6] ftrace: define seq_file only for FMODE_READ
Message-ID: <20201008033416.anmamvegf2g2zfwv@master>
Reply-To: Wei Yang <richard.weiyang@gmail.com>
References: <20200831031104.23322-1-richard.weiyang@linux.alibaba.com>
 <20200831031104.23322-2-richard.weiyang@linux.alibaba.com>
 <20201006103638.153e39d3@gandalf.local.home>
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On Tue, Oct 06, 2020 at 10:36:38AM -0400, Steven Rostedt wrote:
>On Mon, 31 Aug 2020 11:10:59 +0800
>Wei Yang <richard.weiyang@linux.alibaba.com> wrote:
>
>> The purpose of the operation is to get ftrace_iterator, which is embedded
>> in file or seq_file for FMODE_WRITE/FMODE_READ respectively. Since we
>> don't have a seq_file for FMODE_WRITE case, it is meaningless to cast
>> file->private_data to seq_file.
>> 
>> Let's move the definition when there is a valid seq_file.
>
>I didn't pull in this patch because I find the original more expressive,
>and there's really no benefit in changing it.
>

Got it, thanks

>-- Steve
>
>
>> 
>> Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
>> ---
>>  kernel/trace/ftrace.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
>> index edc233122598..12cb535769bc 100644
>> --- a/kernel/trace/ftrace.c
>> +++ b/kernel/trace/ftrace.c
>> @@ -5558,7 +5558,6 @@ static void __init set_ftrace_early_filters(void)
>>  
>>  int ftrace_regex_release(struct inode *inode, struct file *file)
>>  {
>> -	struct seq_file *m = (struct seq_file *)file->private_data;
>>  	struct ftrace_iterator *iter;
>>  	struct ftrace_hash **orig_hash;
>>  	struct trace_parser *parser;
>> @@ -5566,6 +5565,7 @@ int ftrace_regex_release(struct inode *inode, struct file *file)
>>  	int ret;
>>  
>>  	if (file->f_mode & FMODE_READ) {
>> +		struct seq_file *m = file->private_data;
>>  		iter = m->private;
>>  		seq_release(inode, file);
>>  	} else

-- 
Wei Yang
Help you, Help me