[PATCH 1/6] ftrace: define seq_file only for FMODE_READ

[Wei Yang]

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.weiy...@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)