Re: [PATCH] block: bio: Use struct_size() in kmalloc()

From: Jens Axboe
Date: Sat Jun 15 2019 - 03:50:39 EST


On 6/10/19 9:04 AM, 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 bio_map_data {
> ...
> struct iovec iov[];
> };
>
> instance = kmalloc(sizeof(sizeof(struct bio_map_data) + sizeof(struct iovec) *
> count, GFP_KERNEL);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = kmalloc(struct_size(instance, iov, count), GFP_KERNEL);
>
> This code was detected with the help of Coccinelle.

Applied, thanks.

--
Jens Axboe