From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Johannes Berg <johannes@sipsolutions.net>,
"David S. Miller" <davem@davemloft.net>
Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH][next] cfg80211: Use struct_size() in kzalloc()
Date: Wed, 3 Apr 2019 10:31:51 -0500 [thread overview]
Message-ID: <20190403153151.GA32496@embeddedor> (raw)
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 foo {
int stuff;
struct boo entry[];
};
size = sizeof(struct foo) + count * sizeof(struct boo);
instance = kzalloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL)
Notice that, in this case, variable size_of_regd is not necessary,
hence it is removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
net/wireless/reg.c | 23 +++++++----------------
1 file changed, 7 insertions(+), 16 deletions(-)
diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 0ba778f371cb..816425ffe05a 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -427,14 +427,10 @@ static const struct ieee80211_regdomain *
reg_copy_regd(const struct ieee80211_regdomain *src_regd)
{
struct ieee80211_regdomain *regd;
- int size_of_regd;
unsigned int i;
- size_of_regd =
- sizeof(struct ieee80211_regdomain) +
- src_regd->n_reg_rules * sizeof(struct ieee80211_reg_rule);
-
- regd = kzalloc(size_of_regd, GFP_KERNEL);
+ regd = kzalloc(struct_size(regd, reg_rules, src_regd->n_reg_rules),
+ GFP_KERNEL);
if (!regd)
return ERR_PTR(-ENOMEM);
@@ -948,12 +944,10 @@ static int regdb_query_country(const struct fwdb_header *db,
unsigned int ptr = be16_to_cpu(country->coll_ptr) << 2;
struct fwdb_collection *coll = (void *)((u8 *)db + ptr);
struct ieee80211_regdomain *regdom;
- unsigned int size_of_regd, i;
-
- size_of_regd = sizeof(struct ieee80211_regdomain) +
- coll->n_rules * sizeof(struct ieee80211_reg_rule);
+ unsigned int i;
- regdom = kzalloc(size_of_regd, GFP_KERNEL);
+ regdom = kzalloc(struct_size(regdom, reg_rules, coll->n_rules),
+ GFP_KERNEL);
if (!regdom)
return -ENOMEM;
@@ -1489,7 +1483,7 @@ static struct ieee80211_regdomain *
regdom_intersect(const struct ieee80211_regdomain *rd1,
const struct ieee80211_regdomain *rd2)
{
- int r, size_of_regd;
+ int r;
unsigned int x, y;
unsigned int num_rules = 0;
const struct ieee80211_reg_rule *rule1, *rule2;
@@ -1520,10 +1514,7 @@ regdom_intersect(const struct ieee80211_regdomain *rd1,
if (!num_rules)
return NULL;
- size_of_regd = sizeof(struct ieee80211_regdomain) +
- num_rules * sizeof(struct ieee80211_reg_rule);
-
- rd = kzalloc(size_of_regd, GFP_KERNEL);
+ rd = kzalloc(struct_size(rd, reg_rules, num_rules), GFP_KERNEL);
if (!rd)
return NULL;
--
2.21.0
reply other threads:[~2019-04-03 15:31 UTC|newest]
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