From: "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx>
Subject: 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
{
i ...
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@xxxxxxxxxxxxxx>
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Changwei Ge <gechangwei@xxxxxxx>
Cc: Gang He <ghe@xxxxxxxx>
Cc: Jun Piao <piaojun@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/dlm/dlmrecovery.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
--- a/fs/ocfs2/dlm/dlmrecovery.c~ocfs2-dlm-use-struct_size-helper
+++ a/fs/ocfs2/dlm/dlmrecovery.c
@@ -1109,7 +1109,7 @@ static int dlm_send_mig_lockres_msg(stru
{
u64 mig_cookie = be64_to_cpu(mres->mig_cookie);
int mres_total_locks = be32_to_cpu(mres->total_locks);
- int sz, ret = 0, status = 0;
+ int ret = 0, status = 0;
u8 orig_flags = mres->flags,
orig_master = mres->master;
@@ -1117,9 +1117,6 @@ static int dlm_send_mig_lockres_msg(stru
if (!mres->num_locks)
return 0;
- sz = sizeof(struct dlm_migratable_lockres) +
- (mres->num_locks * sizeof(struct dlm_migratable_lock));
-
/* add an all-done flag if we reached the last lock */
orig_flags = mres->flags;
BUG_ON(total_locks > mres_total_locks);
@@ -1133,7 +1130,8 @@ static int dlm_send_mig_lockres_msg(stru
/* send it */
ret = o2net_send_message(DLM_MIG_LOCKRES_MSG, dlm->key, mres,
- sz, send_to, &status);
+ struct_size(mres, ml, mres->num_locks),
+ send_to, &status);
if (ret < 0) {
/* XXX: negative status is not handled.
* this will end up killing this node. */
_
