* [PATCH] qxl: Use struct_size() in kzalloc()
@ 2019-01-08 16:21 Gustavo A. R. Silva
2019-01-09 8:32 ` Gerd Hoffmann
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-08 16:21 UTC (permalink / raw)
To: Dave Airlie, Gerd Hoffmann, David Airlie, Daniel Vetter
Cc: virtualization, dri-devel, linux-kernel, 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/gpu/drm/qxl/qxl_display.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
index ce0b9c40fc21..c8642712412e 100644
--- a/drivers/gpu/drm/qxl/qxl_display.c
+++ b/drivers/gpu/drm/qxl/qxl_display.c
@@ -48,8 +48,8 @@ static int qxl_alloc_client_monitors_config(struct qxl_device *qdev,
}
if (!qdev->client_monitors_config) {
qdev->client_monitors_config = kzalloc(
- sizeof(struct qxl_monitors_config) +
- sizeof(struct qxl_head) * count, GFP_KERNEL);
+ struct_size(qdev->client_monitors_config,
+ heads, count), GFP_KERNEL);
if (!qdev->client_monitors_config)
return -ENOMEM;
}
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] qxl: Use struct_size() in kzalloc()
2019-01-08 16:21 [PATCH] qxl: Use struct_size() in kzalloc() Gustavo A. R. Silva
@ 2019-01-09 8:32 ` Gerd Hoffmann
0 siblings, 0 replies; 2+ messages in thread
From: Gerd Hoffmann @ 2019-01-09 8:32 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Dave Airlie, David Airlie, Daniel Vetter, virtualization,
dri-devel, linux-kernel
On Tue, Jan 08, 2019 at 10:21:52AM -0600, 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.
Patch queued up.
thanks,
Gerd
^ permalink raw reply [flat|nested] 2+ messages in thread
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