make-ext4_ext_drop_refs-allow-NULL-arguments

   1 ext4: allow a NULL argument to ext4_ext_drop_refs()
   2
   3 Teach ext4_ext_drop_refs() to accept a NULL argument, much like
   4 kfree().  This allows us to drop a lot of checks to make sure path is
   5 non-NULL before calling ext4_ext_drop_refs().
   6
   7 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
   8 ---
   9  fs/ext4/extents.c        | 48 ++++++++++++++++++------------------------------
  10  fs/ext4/extents_status.c |  6 ++----
  11  fs/ext4/migrate.c        |  6 ++----
  12  fs/ext4/move_extent.c    | 20 +++++++-------------
  13  4 files changed, 29 insertions(+), 51 deletions(-)
  14
  15 diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
  16 index 62aa508..17a1f6f 100644
  17 --- a/fs/ext4/extents.c
  18 +++ b/fs/ext4/extents.c
  19 @@ -701,9 +701,11 @@ static void ext4_ext_show_move(struct inode *inode, struct ext4_ext_path *path,
  20
  21  void ext4_ext_drop_refs(struct ext4_ext_path *path)
  22  {
  23 -       int depth = path->p_depth;
  24 -       int i;
  25 +       int depth, i;
  26
  27 +       if (!path)
  28 +               return;
  29 +       depth = path->p_depth;
  30         for (i = 0; i <= depth; i++, path++)
  31                 if (path->p_bh) {
  32                         brelse(path->p_bh);
  33 @@ -2117,10 +2119,8 @@ merge:
  34         err = ext4_ext_dirty(handle, inode, path + path->p_depth);
  35
  36  cleanup:
  37 -       if (npath) {
  38 -               ext4_ext_drop_refs(npath);
  39 -               kfree(npath);
  40 -       }
  41 +       ext4_ext_drop_refs(npath);
  42 +       kfree(npath);
  43         return err;
  44  }
  45
  46 @@ -2275,11 +2275,8 @@ static int ext4_fill_fiemap_extents(struct inode *inode,
  47                 block = es.es_lblk + es.es_len;
  48         }
  49
  50 -       if (path) {
  51 -               ext4_ext_drop_refs(path);
  52 -               kfree(path);
  53 -       }
  54 -
  55 +       ext4_ext_drop_refs(path);
  56 +       kfree(path);
  57         return err;
  58  }
  59
  60 @@ -3010,11 +3007,9 @@ again:
  61                 }
  62         }
  63  out:
  64 -       if (path) {
  65 -               ext4_ext_drop_refs(path);
  66 -               kfree(path);
  67 -               path = NULL;
  68 -       }
  69 +       ext4_ext_drop_refs(path);
  70 +       kfree(path);
  71 +       path = NULL;
  72         if (err == -EAGAIN)
  73                 goto again;
  74         ext4_journal_stop(handle);
  75 @@ -4617,10 +4612,8 @@ out:
  76         map->m_pblk = newblock;
  77         map->m_len = allocated;
  78  out2:
  79 -       if (path) {
  80 -               ext4_ext_drop_refs(path);
  81 -               kfree(path);
  82 -       }
  83 +       ext4_ext_drop_refs(path);
  84 +       kfree(path);
  85
  86         trace_ext4_ext_map_blocks_exit(inode, flags, map,
  87                                        err ? err : allocated);
  88 @@ -5692,16 +5685,11 @@ ext4_swap_extents(handle_t *handle, struct inode *inode1,
  89                 count -= len;
  90
  91         repeat:
  92 -               if (path1) {
  93 -                       ext4_ext_drop_refs(path1);
  94 -                       kfree(path1);
  95 -                       path1 = NULL;
  96 -               }
  97 -               if (path2) {
  98 -                       ext4_ext_drop_refs(path2);
  99 -                       kfree(path2);
 100 -                       path2 = NULL;
 101 -               }
 102 +               ext4_ext_drop_refs(path1);
 103 +               kfree(path1);
 104 +               ext4_ext_drop_refs(path2);
 105 +               kfree(path2);
 106 +               path1 = path2 = NULL;
 107         }
 108         return replaced_count;
 109  }
 110 diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
 111 index 0b7e28e..8ffff96 100644
 112 --- a/fs/ext4/extents_status.c
 113 +++ b/fs/ext4/extents_status.c
 114 @@ -499,10 +499,8 @@ static void ext4_es_insert_extent_ext_check(struct inode *inode,
 115                 }
 116         }
 117  out:
 118 -       if (path) {
 119 -               ext4_ext_drop_refs(path);
 120 -               kfree(path);
 121 -       }
 122 +       ext4_ext_drop_refs(path);
 123 +       kfree(path);
 124  }
 125
 126  static void ext4_es_insert_extent_ind_check(struct inode *inode,
 127 diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
 128 index aff7bdf..061c300 100644
 129 --- a/fs/ext4/migrate.c
 130 +++ b/fs/ext4/migrate.c
 131 @@ -84,10 +84,8 @@ static int finish_range(handle_t *handle, struct inode *inode,
 132         retval = ext4_ext_insert_extent(handle, inode, &path, &newext, 0);
 133  err_out:
 134         up_write((&EXT4_I(inode)->i_data_sem));
 135 -       if (path) {
 136 -               ext4_ext_drop_refs(path);
 137 -               kfree(path);
 138 -       }
 139 +       ext4_ext_drop_refs(path);
 140 +       kfree(path);
 141         lb->first_pblock = 0;
 142         return retval;
 143  }
 144 diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c
 145 index 5e2465a..a34c076 100644
 146 --- a/fs/ext4/move_extent.c
 147 +++ b/fs/ext4/move_extent.c
 148 @@ -113,10 +113,8 @@ mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
 149         }
 150         ret = 1;
 151  out:
 152 -       if (path) {
 153 -               ext4_ext_drop_refs(path);
 154 -               kfree(path);
 155 -       }
 156 +       ext4_ext_drop_refs(path);
 157 +       kfree(path);
 158         return ret;
 159  }
 160
 161 @@ -711,11 +709,9 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 orig_blk,
 162                 o_start += cur_len;
 163                 d_start += cur_len;
 164         repeat:
 165 -               if (path) {
 166 -                       ext4_ext_drop_refs(path);
 167 -                       kfree(path);
 168 -                       path = NULL;
 169 -               }
 170 +               ext4_ext_drop_refs(path);
 171 +               kfree(path);
 172 +               path = NULL;
 173         }
 174         *moved_len = o_start - orig_blk;
 175         if (*moved_len > len)
 176 @@ -727,10 +723,8 @@ out:
 177                 ext4_discard_preallocations(donor_inode);
 178         }
 179
 180 -       if (path) {
 181 -               ext4_ext_drop_refs(path);
 182 -               kfree(path);
 183 -       }
 184 +       ext4_ext_drop_refs(path);
 185 +       kfree(path);
 186         ext4_double_up_write_data_sem(orig_inode, donor_inode);
 187         ext4_inode_resume_unlocked_dio(orig_inode);
 188         ext4_inode_resume_unlocked_dio(donor_inode);