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ocfs2/dlm: use struct_size() helper
authorGustavo A. R. Silva <gustavo@embeddedor.com>
Fri, 12 Jul 2019 03:52:58 +0000 (20:52 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 12 Jul 2019 18:05:41 +0000 (11:05 -0700)
commit0e71666b8b9e21e4cb5d805219eb5ed7c5617ca3
treec791bc0d2604fe47185af1228fe762ffe1928d6d
parente926d8a1e8675422e53104855a7bedec82fb570f
ocfs2/dlm: use struct_size() helper

One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array.  For example:

  struct dlm_migratable_lockres
  {
          ...
          struct dlm_migratable_lock ml[0];  // 16 bytes each, begins at byte 112
  };

Make use of the struct_size() helper instead of an open-coded version in
order to avoid any potential type mistakes.

So, replace the following form:

   sizeof(struct dlm_migratable_lockres) + (mres->num_locks * sizeof(struct dlm_migratable_lock))

with:

   struct_size(mres, ml, mres->num_locks)

Notice that, in this case, variable sz is not necessary, hence it is
removed.

This code was detected with the help of Coccinelle.

Link: http://lkml.kernel.org/r/20190605204926.GA24467@embeddedor
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/ocfs2/dlm/dlmrecovery.c