Re: [PATCH 1/3] wifi: ipw2x00: convert ipw_fw_error->elem to flexible array[]

[Johannes Berg <johannes@sipsolutions.net>]

On Tue, 2023-02-28 at 09:44 -0800, Jacob Keller wrote:
> 
> Previous to this change, error struct has two pointers to sections of
> memory allocated at the end of the buffer.
> 
> The code used to be:
> 
> -	error = kmalloc(sizeof(*error) +
> -			sizeof(*error->elem) * elem_len +
> -			sizeof(*error->log) * log_len, GFP_ATOMIC);
> 
> i.e. the elem_len is multiplying sizeof(*error->elem).
> 
> The code is essentially trying to get two flexible arrays in the same
> allocation, and its a bit messy to do that. I don't see how elem_len
> could be anything other than "number of elems" given this code I removed.

Yeah, you're right. I was thinking of more modern HW/FW too much I
guess, I see now even in the driver we have an array walk here (and it
trusts the elem_len from firmware... ahrg!)

> I posted these mainly because I was trying to resolve all of the hits
> that were found by the coccinelle patch I made, posted at [1]. I wanted
> to get it to run clean so that we had no more struct_size hits.
> 
> Dropping this would just make that patch have some hits until the driver
> is removed, eventually...
> 
> Not really a big deal to me, I just didn't want to post a coccinelle
> patch without also trying to fix the handful of problems it reported,
> since the total number of reports was small.
> 

Makes sense. I don't think we'll drop the driver at any point soon, but
I also don't see it being changed much :)

johannes