diff mbox series

[next] qtnfmac: Use struct_size() in kzalloc()

Message ID 20190607191745.GA19120@embeddedor (mailing list archive)
State Accepted
Commit 9a1ace64ca3b713e1029fed83dc22d8740b20aba
Delegated to: Kalle Valo
Headers show
Series [next] qtnfmac: Use struct_size() in kzalloc() | expand

Commit Message

Gustavo A. R. Silva June 7, 2019, 7:17 p.m. UTC
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 ieee80211_regdomain {
	...
        struct ieee80211_reg_rule reg_rules[];
};

instance = kzalloc(sizeof(*mac->rd) +
                          sizeof(struct ieee80211_reg_rule) *
                          count, 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, reg_rules, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/net/wireless/quantenna/qtnfmac/commands.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Comments

Sergey Matyukevich June 10, 2019, 4:14 p.m. UTC | #1
> 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 ieee80211_regdomain {
>         ...
>         struct ieee80211_reg_rule reg_rules[];
> };
> 
> instance = kzalloc(sizeof(*mac->rd) +
>                           sizeof(struct ieee80211_reg_rule) *
>                           count, 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, reg_rules, count), GFP_KERNEL);
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
 
Hi Gustavo,
Thanks for the patch !

Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>

Regards,
Sergey
Kalle Valo June 25, 2019, 5:01 a.m. UTC | #2
"Gustavo A. R. Silva" <gustavo@embeddedor.com> wrote:

> 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 ieee80211_regdomain {
> 	...
>         struct ieee80211_reg_rule reg_rules[];
> };
> 
> instance = kzalloc(sizeof(*mac->rd) +
>                           sizeof(struct ieee80211_reg_rule) *
>                           count, 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, reg_rules, count), GFP_KERNEL);
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> Reviewed-by: Sergey Matyukevich <sergey.matyukevich.os@quantenna.com>

Patch applied to wireless-drivers-next.git, thanks.

9a1ace64ca3b qtnfmac: Use struct_size() in kzalloc()
diff mbox series

Patch

diff --git a/drivers/net/wireless/quantenna/qtnfmac/commands.c b/drivers/net/wireless/quantenna/qtnfmac/commands.c
index 459f6b81d2eb..dc0c7244b60e 100644
--- a/drivers/net/wireless/quantenna/qtnfmac/commands.c
+++ b/drivers/net/wireless/quantenna/qtnfmac/commands.c
@@ -1011,9 +1011,8 @@  qtnf_parse_variable_mac_info(struct qtnf_wmac *mac,
 	if (WARN_ON(resp->n_reg_rules > NL80211_MAX_SUPP_REG_RULES))
 		return -E2BIG;
 
-	mac->rd = kzalloc(sizeof(*mac->rd) +
-			  sizeof(struct ieee80211_reg_rule) *
-			  resp->n_reg_rules, GFP_KERNEL);
+	mac->rd = kzalloc(struct_size(mac->rd, reg_rules, resp->n_reg_rules),
+			  GFP_KERNEL);
 	if (!mac->rd)
 		return -ENOMEM;