linux-kernel - Re: [PATCH] lib: objagg: Use struct

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Date:   Wed, 5 Jun 2019 17:21:37 +0200
From:   Jiri Pirko <jiri@...nulli.us>
To:     "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Cc:     Jiri Pirko <jiri@...lanox.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] lib: objagg: Use struct_size() in kzalloc()

Wed, Jun 05, 2019 at 04:45:16PM CEST, gustavo@...eddedor.com 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 objagg_stats {
>	...
>        struct objagg_obj_stats_info stats_info[];
>};
>
>size = sizeof(*objagg_stats) + sizeof(objagg_stats->stats_info[0]) * count;
>instance = kzalloc(size, 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, stats_info, count), GFP_KERNEL);
>
>Notice that, in this case, variable alloc_size is not necessary, hence it
>is removed.
>
>This code was detected with the help of Coccinelle.
>
>Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>

Acked-by: Jiri Pirko <jiri@...lanox.com>