[PATCH] mtd: lpddr: Use struct_size() in kzalloc()

[PATCH] mtd: lpddr: Use struct_size() in kzalloc()

[Gustavo A. R. Silva]

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;
    void *entry[];
};

instance = kzalloc(sizeof(struct foo) + sizeof(void *) * 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, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/mtd/lpddr/qinfo_probe.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/lpddr/qinfo_probe.c b/drivers/mtd/lpddr/qinfo_probe.c
index 69f2112340b1..175bdc3b72f4 100644
--- a/drivers/mtd/lpddr/qinfo_probe.c
+++ b/drivers/mtd/lpddr/qinfo_probe.c
@@ -181,8 +181,8 @@ static struct lpddr_private *lpddr_probe_chip(struct map_info *map)
 	lpddr.numchips = 1;
 
 	numvirtchips = lpddr.numchips * lpddr.qinfo->HWPartsNum;
-	retlpddr = kzalloc(sizeof(struct lpddr_private) +
-			numvirtchips * sizeof(struct flchip), GFP_KERNEL);
+	retlpddr = kzalloc(struct_size(retlpddr, chips, numvirtchips),
+			   GFP_KERNEL);
 	if (!retlpddr)
 		return NULL;
 
-- 
2.20.1

mtd: lpddr: Use struct_size() in kzalloc()

[Boris Brezillon]

From: Boris Brezillon <boris.brezillon@bootlin.com>

On Tue, 2019-01-08 at 21:09:46 UTC, "Gustavo A. R. Silva" 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 foo {
>     int stuff;
>     void *entry[];
> };
> 
> instance = kzalloc(sizeof(struct foo) + sizeof(void *) * 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, entry, count), GFP_KERNEL);
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Applied to http://git.infradead.org/linux-mtd.git mtd/next, thanks.

Boris