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From:   Wei Yang <richard.weiyang@linux.alibaba.com>
To:     rostedt@goodmis.org, mingo@redhat.com
Cc:     linux-kernel@vger.kernel.org,
        Wei Yang <richard.weiyang@linux.alibaba.com>
Subject: [PATCH 1/6] ftrace: define seq_file only for FMODE_READ
Date:   Mon, 31 Aug 2020 11:10:59 +0800
Message-Id: <20200831031104.23322-2-richard.weiyang@linux.alibaba.com>
In-Reply-To: <20200831031104.23322-1-richard.weiyang@linux.alibaba.com>
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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.

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
-- 
2.20.1 (Apple Git-117)