eCryptfs: file->private_data is always valid

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=2000f5beabc9c6baf084de5f7879975408e3652c
Commit:     2000f5beabc9c6baf084de5f7879975408e3652c
Parent:     42a2d923cc349583ebf6fdd52a7d35e1c2f7e6bd
Author:     Tyler Hicks <tyhicks at canonical.com>
AuthorDate: Wed Nov 13 10:09:42 2013 -0800
Committer:  Tyler Hicks <tyhicks at canonical.com>
CommitDate: Thu Nov 14 12:12:15 2013 -0800

    eCryptfs: file->private_data is always valid
    
    When accessing the lower_file pointer located in private_data of
    eCryptfs files, there is no need to check to see if the private_data
    pointer has been initialized to a non-NULL value. The file->private_data
    and file->private_data->lower_file pointers are always initialized to
    non-NULL values in ecryptfs_open().
    
    This change quiets a Smatch warning:
    
      CHECK   /var/scm/kernel/linux/fs/ecryptfs/file.c
    fs/ecryptfs/file.c:321 ecryptfs_unlocked_ioctl() error: potential NULL dereference 'lower_file'.
    fs/ecryptfs/file.c:335 ecryptfs_compat_ioctl() error: potential NULL dereference 'lower_file'.
    
    Signed-off-by: Tyler Hicks <tyhicks at canonical.com>
    Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
    Reviewed-by: Geyslan G. Bem <geyslan at gmail.com>
    Cc: Al Viro <viro at zeniv.linux.org.uk>
---
 fs/ecryptfs/file.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c
index 2229a74..b1eaa7a 100644
--- a/fs/ecryptfs/file.c
+++ b/fs/ecryptfs/file.c
@@ -313,11 +313,9 @@ static int ecryptfs_fasync(int fd, struct file *file, int flag)
 static long
 ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
-	struct file *lower_file = NULL;
+	struct file *lower_file = ecryptfs_file_to_lower(file);
 	long rc = -ENOTTY;
 
-	if (ecryptfs_file_to_private(file))
-		lower_file = ecryptfs_file_to_lower(file);
 	if (lower_file->f_op->unlocked_ioctl)
 		rc = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
 	return rc;
@@ -327,11 +325,9 @@ ecryptfs_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 static long
 ecryptfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
-	struct file *lower_file = NULL;
+	struct file *lower_file = ecryptfs_file_to_lower(file);
 	long rc = -ENOIOCTLCMD;
 
-	if (ecryptfs_file_to_private(file))
-		lower_file = ecryptfs_file_to_lower(file);
 	if (lower_file->f_op && lower_file->f_op->compat_ioctl)
 		rc = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
 	return rc;