use-BUG-instead-of-BUG_ON

   1 ext4: use BUG() instead of BUG_ON(1)
   2
   3 From: Arnd Bergmann <arnd@arndb.de>
   4
   5 BUG_ON(1) leads to bogus warnings from clang when
   6 CONFIG_PROFILE_ANNOTATED_BRANCHES is set:
   7
   8  fs/ext4/inode.c:544:4: error: variable 'retval' is used uninitialized whenever 'if' condition is false
   9       [-Werror,-Wsometimes-uninitialized]
  10                         BUG_ON(1);
  11                         ^~~~~~~~~
  12  include/asm-generic/bug.h:61:36: note: expanded from macro 'BUG_ON'
  13                                    ^~~~~~~~~~~~~~~~~~~
  14  include/linux/compiler.h:48:23: note: expanded from macro 'unlikely'
  15                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  16  fs/ext4/inode.c:591:6: note: uninitialized use occurs here
  17         if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
  18             ^~~~~~
  19  fs/ext4/inode.c:544:4: note: remove the 'if' if its condition is always true
  20                         BUG_ON(1);
  21                         ^
  22  include/asm-generic/bug.h:61:32: note: expanded from macro 'BUG_ON'
  23                                ^
  24  fs/ext4/inode.c:502:12: note: initialize the variable 'retval' to silence this warning
  25
  26 Change it to BUG() so clang can see that this code path can never
  27 continue.
  28
  29 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
  30 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
  31 Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
  32 Reviewed-by: Jan Kara <jack@suse.cz>
  33 ---
  34  fs/ext4/extents_status.c | 4 ++--
  35  fs/ext4/inode.c          | 4 ++--
  36  2 files changed, 4 insertions(+), 4 deletions(-)
  37
  38 diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
  39 index 2b439afafe13..023a3eb3afa3 100644
  40 --- a/fs/ext4/extents_status.c
  41 +++ b/fs/ext4/extents_status.c
  42 @@ -711,7 +711,7 @@ static void ext4_es_insert_extent_ind_check(struct inode *inode,
  43                          * We don't need to check unwritten extent because
  44                          * indirect-based file doesn't have it.
  45                          */
  46 -                       BUG_ON(1);
  47 +                       BUG();
  48                 }
  49         } else if (retval == 0) {
  50                 if (ext4_es_is_written(es)) {
  51 @@ -780,7 +780,7 @@ static int __es_insert_extent(struct inode *inode, struct extent_status *newes)
  52                         }
  53                         p = &(*p)->rb_right;
  54                 } else {
  55 -                       BUG_ON(1);
  56 +                       BUG();
  57                         return -EINVAL;
  58                 }
  59         }
  60 diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
  61 index b32a57bc5d5d..190f0478582a 100644
  62 --- a/fs/ext4/inode.c
  63 +++ b/fs/ext4/inode.c
  64 @@ -541,7 +541,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
  65                         map->m_len = retval;
  66                         retval = 0;
  67                 } else {
  68 -                       BUG_ON(1);
  69 +                       BUG();
  70                 }
  71  #ifdef ES_AGGRESSIVE_TEST
  72                 ext4_map_blocks_es_recheck(handle, inode, map,
  73 @@ -1876,7 +1876,7 @@ static int ext4_da_map_blocks(struct inode *inode, sector_t iblock,
  74                 else if (ext4_es_is_unwritten(&es))
  75                         map->m_flags |= EXT4_MAP_UNWRITTEN;
  76                 else
  77 -                       BUG_ON(1);
  78 +                       BUG();
  79
  80  #ifdef ES_AGGRESSIVE_TEST
  81                 ext4_map_blocks_es_recheck(NULL, inode, map, &orig_map, 0);
  82 --
  83 2.20.0
  84
  85