Re: [PATCH][next] mwifiex: usb: Replace one-element array with flexible-array member

[Brian Norris]

On Mon, Aug 9, 2021 at 2:08 PM Gustavo A. R. Silva
<gustavoars@xxxxxxxxxx> wrote:
>
> There is a regular need in the kernel to provide a way to declare having
> a dynamically sized set of trailing elements in a structure. Kernel code
> should always use “flexible array members”[1] for these cases. The older
> style of one-element or zero-length arrays should no longer be used[2].
>
> This helps with the ongoing efforts to globally enable -Warray-bounds
> and get us closer to being able to tighten the FORTIFY_SOURCE routines
> on memcpy().
>
> This issue was found with the help of Coccinelle and audited and fixed,
> manually.
>
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays
>
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/109
> Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>

An important part of your patch rationale should include determining
that the 1-length wasn't actually important anywhere. I double checked
for you, and nobody seemed to be relying on 'sizeof struct fw_data' at
all, so this should be OK:

Reviewed-by: Brian Norris <briannorris@xxxxxxxxxxxx>