Re: [PATCH][next] bcache: Use struct_size() in kzalloc()

Coly Li
2020-06-18T05:38:59Z

On 2020/6/18 06:27, Gustavo A. R. Silva wrote:
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes.
>
> This code was detected with the help of Coccinelle and, audited and
> fixed manually.
>
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> ---
> drivers/md/bcache/writeback.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
> index 1cf1e5016cb9..c0db3c860179 100644
> --- a/drivers/md/bcache/writeback.c
> +++ b/drivers/md/bcache/writeback.c
> @@ -459,10 +459,8 @@ static void read_dirty(struct cached_dev *dc)
> for (i = 0; i < nk; i++) {
> w = keys[i];
>
> - io = kzalloc(sizeof(struct dirty_io) +
> - sizeof(struct bio_vec) *
> - DIV_ROUND_UP(KEY_SIZE(&w->key),
> - PAGE_SECTORS),
> + io = kzalloc(struct_size(io, bio.bi_inline_vecs,
^^^^^^^^^^^^^^^^^^
I like this :-)

> + DIV_ROUND_UP(KEY_SIZE(&w->key), PAGE_SECTORS)),

The above line seems too long for 80 characters limitation. Does
checkpatch.pl complain for this ?

Thanks.

Coly Li

> GFP_KERNEL);
> if (!io)
> goto err;
>