fs: Make unload_nls() NULL pointer safe

Most call sites of unload_nls() do:
	if (nls)
		unload_nls(nls);

Check the pointer inside unload_nls() like we do in kfree() and
simplify the call sites.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Steve French <sfrench@us.ibm.com>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Petr Vandrovec <vandrove@vc.cvut.cz>
Cc: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

12 files changed, 27 insertions, 69 deletions

diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
index dd376c124e71..33baf27fac78 100644
--- a/fs/befs/linuxvfs.c
+++ b/fs/befs/linuxvfs.c
@@ -737,12 +737,7 @@ befs_put_super(struct super_block *sb)
 {
         kfree(BEFS_SB(sb)->mount_opts.iocharset);
         BEFS_SB(sb)->mount_opts.iocharset = NULL;
-
-        if (BEFS_SB(sb)->nls) {
-                unload_nls(BEFS_SB(sb)->nls);
-                BEFS_SB(sb)->nls = NULL;
-        }
-
+        unload_nls(BEFS_SB(sb)->nls);
         kfree(sb->s_fs_info);
         sb->s_fs_info = NULL;
 }
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index d79ce2e95c23..90c5b39f0313 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -185,8 +185,7 @@ out_mount_failed:
                         cifs_sb->mountdata = NULL;
                 }
 #endif
-                if (cifs_sb->local_nls)
-                        unload_nls(cifs_sb->local_nls);
+                unload_nls(cifs_sb->local_nls);
                 kfree(cifs_sb);
         }
         return rc;
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 8970d8c49bb0..04629d1302fc 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -470,19 +470,11 @@ static void fat_put_super(struct super_block *sb)
 
         iput(sbi->fat_inode);
 
-        if (sbi->nls_disk) {
-                unload_nls(sbi->nls_disk);
-                sbi->nls_disk = NULL;
-                sbi->options.codepage = fat_default_codepage;
-        }
-        if (sbi->nls_io) {
-                unload_nls(sbi->nls_io);
-                sbi->nls_io = NULL;
-        }
-        if (sbi->options.iocharset != fat_default_iocharset) {
+        unload_nls(sbi->nls_disk);
+        unload_nls(sbi->nls_io);
+
+        if (sbi->options.iocharset != fat_default_iocharset)
                 kfree(sbi->options.iocharset);
-                sbi->options.iocharset = fat_default_iocharset;
-        }
 
         sb->s_fs_info = NULL;
         kfree(sbi);
diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c
index 7b6165f25fbe..8bbe03c3f6d5 100644
--- a/fs/hfs/mdb.c
+++ b/fs/hfs/mdb.c
@@ -344,10 +344,8 @@ void hfs_mdb_put(struct super_block *sb)
         brelse(HFS_SB(sb)->mdb_bh);
         brelse(HFS_SB(sb)->alt_mdb_bh);
 
-        if (HFS_SB(sb)->nls_io)
-                unload_nls(HFS_SB(sb)->nls_io);
-        if (HFS_SB(sb)->nls_disk)
-                unload_nls(HFS_SB(sb)->nls_disk);
+        unload_nls(HFS_SB(sb)->nls_io);
+        unload_nls(HFS_SB(sb)->nls_disk);
 
         free_pages((unsigned long)HFS_SB(sb)->bitmap, PAGE_SIZE < 8192 ? 1 : 0);
         kfree(HFS_SB(sb));
diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index c0759fe0855b..43022f3d5148 100644
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -229,8 +229,7 @@ static void hfsplus_put_super(struct super_block *sb)
         iput(HFSPLUS_SB(sb).alloc_file);
         iput(HFSPLUS_SB(sb).hidden_dir);
         brelse(HFSPLUS_SB(sb).s_vhbh);
-        if (HFSPLUS_SB(sb).nls)
-                unload_nls(HFSPLUS_SB(sb).nls);
+        unload_nls(HFSPLUS_SB(sb).nls);
         kfree(sb->s_fs_info);
         sb->s_fs_info = NULL;
 
@@ -464,8 +463,7 @@ out:
 
 cleanup:
         hfsplus_put_super(sb);
-        if (nls)
-                unload_nls(nls);
+        unload_nls(nls);
         return err;
 }
 
diff --git a/fs/isofs/inode.c b/fs/isofs/inode.c
index 85f96bc651c7..6b4dcd4f2943 100644
--- a/fs/isofs/inode.c
+++ b/fs/isofs/inode.c
@@ -46,10 +46,7 @@ static void isofs_put_super(struct super_block *sb)
 #ifdef CONFIG_JOLIET
         lock_kernel();
 
-        if (sbi->s_nls_iocharset) {
-                unload_nls(sbi->s_nls_iocharset);
-                sbi->s_nls_iocharset = NULL;
-        }
+        unload_nls(sbi->s_nls_iocharset);
 
         unlock_kernel();
 #endif
@@ -912,8 +909,7 @@ out_no_root:
                 printk(KERN_WARNING "%s: get root inode failed\n", __func__);
 out_no_inode:
 #ifdef CONFIG_JOLIET
-        if (sbi->s_nls_iocharset)
-                unload_nls(sbi->s_nls_iocharset);
+        unload_nls(sbi->s_nls_iocharset);
 #endif
         goto out_freesbi;
 out_no_read:
diff --git a/fs/jfs/super.c b/fs/jfs/super.c
index 37e6dcda8fc8..2234c73fc577 100644
--- a/fs/jfs/super.c
+++ b/fs/jfs/super.c
@@ -178,13 +178,11 @@ static void jfs_put_super(struct super_block *sb)
         rc = jfs_umount(sb);
         if (rc)
                 jfs_err("jfs_umount failed with return code %d", rc);
-        if (sbi->nls_tab)
-                unload_nls(sbi->nls_tab);
-        sbi->nls_tab = NULL;
+
+        unload_nls(sbi->nls_tab);
 
         truncate_inode_pages(sbi->direct_inode->i_mapping, 0);
         iput(sbi->direct_inode);
-        sbi->direct_inode = NULL;
 
         kfree(sbi);
 
@@ -347,8 +345,7 @@ static int parse_options(char *options, struct super_block *sb, s64 *newLVSize,
 
         if (nls_map != (void *) -1) {
                 /* Discard old (if remount) */
-                if (sbi->nls_tab)
-                        unload_nls(sbi->nls_tab);
+                unload_nls(sbi->nls_tab);
                 sbi->nls_tab = nls_map;
         }
         return 1;
diff --git a/fs/ncpfs/inode.c b/fs/ncpfs/inode.c
index b99ce205b1bd..cf98da1be23e 100644
--- a/fs/ncpfs/inode.c
+++ b/fs/ncpfs/inode.c
@@ -746,16 +746,8 @@ static void ncp_put_super(struct super_block *sb)
 
 #ifdef CONFIG_NCPFS_NLS
         /* unload the NLS charsets */
-        if (server->nls_vol)
-        {
-                unload_nls(server->nls_vol);
-                server->nls_vol = NULL;
-        }
-        if (server->nls_io)
-        {
-                unload_nls(server->nls_io);
-                server->nls_io = NULL;
-        }
+        unload_nls(server->nls_vol);
+        unload_nls(server->nls_io);
 #endif /* CONFIG_NCPFS_NLS */
 
         if (server->info_filp)
diff --git a/fs/ncpfs/ioctl.c b/fs/ncpfs/ioctl.c
index 53a7ed7eb9c6..0d58caf4a6e1 100644
--- a/fs/ncpfs/ioctl.c
+++ b/fs/ncpfs/ioctl.c
@@ -223,10 +223,8 @@ ncp_set_charsets(struct ncp_server* server, struct ncp_nls_ioctl __user *arg)
         oldset_io = server->nls_io;
         server->nls_io = iocharset;
 
-        if (oldset_cp)
-                unload_nls(oldset_cp);
-        if (oldset_io)
-                unload_nls(oldset_io);
+        unload_nls(oldset_cp);
+        unload_nls(oldset_io);
 
         return 0;
 }
diff --git a/fs/nls/nls_base.c b/fs/nls/nls_base.c
index 477d37d83b31..2224b4d07bf0 100644
--- a/fs/nls/nls_base.c
+++ b/fs/nls/nls_base.c
@@ -270,7 +270,8 @@ struct nls_table *load_nls(char *charset)
 
 void unload_nls(struct nls_table *nls)
 {
-        module_put(nls->owner);
+        if (nls)
+                module_put(nls->owner);
 }
 
 static const wchar_t charset2uni[256] = {
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index abaaa1cbf8de..80b04770e8e9 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -201,8 +201,7 @@ use_utf8:
                                                 v, old_nls->charset);
                                 nls_map = old_nls;
                         } else /* nls_map */ {
-                                if (old_nls)
-                                        unload_nls(old_nls);
+                                unload_nls(old_nls);
                         }
                 } else if (!strcmp(p, "utf8")) {
                         bool val = false;
@@ -2427,10 +2426,9 @@ static void ntfs_put_super(struct super_block *sb)
                 ntfs_free(vol->upcase);
                 vol->upcase = NULL;
         }
-        if (vol->nls_map) {
-                unload_nls(vol->nls_map);
-                vol->nls_map = NULL;
-        }
+
+        unload_nls(vol->nls_map);
+
         sb->s_fs_info = NULL;
         kfree(vol);
 
diff --git a/fs/smbfs/inode.c b/fs/smbfs/inode.c
index 1402d2d54f52..1c4c8f089970 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -459,14 +459,8 @@ smb_show_options(struct seq_file *s, struct vfsmount *m)
 static void
 smb_unload_nls(struct smb_sb_info *server)
 {
-        if (server->remote_nls) {
-                unload_nls(server->remote_nls);
-                server->remote_nls = NULL;
-        }
-        if (server->local_nls) {
-                unload_nls(server->local_nls);
-                server->local_nls = NULL;
-        }
+        unload_nls(server->remote_nls);
+        unload_nls(server->local_nls);
 }
 
 static void