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From: Vinod Koul <vkoul@kernel.org>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
	dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] dmaengine: bcm-sba-raid: Replace zero-length array with flexible-array member
Date: Thu, 13 Feb 2020 20:16:48 +0530	[thread overview]
Message-ID: <20200213144648.GM2618@vkoul-mobl> (raw)
In-Reply-To: <20200213003703.GA4177@embeddedor.com>

On 12-02-20, 18:37, Gustavo A. R. Silva wrote:
> The current codebase makes use of the zero-length array language
> extension to the C90 standard, but the preferred mechanism to declare
> variable-length types such as these ones is a flexible array member[1][2],
> introduced in C99:
> 
> struct foo {
>         int stuff;
>         struct boo array[];
> };
> 
> By making use of the mechanism above, we will get a compiler warning
> in case the flexible array does not occur last in the structure, which
> will help us prevent some kind of undefined behavior bugs from being
> inadvertently introduced[3] to the codebase from now on.
> 
> Also, notice that, dynamic memory allocations won't be affected by
> this change:
> 
> "Flexible array members have incomplete type, and so the sizeof operator
> may not be applied. As a quirk of the original implementation of
> zero-length arrays, sizeof evaluates to zero."[1]
> 
> This issue was found with the help of Coccinelle.

Applied, thanks

-- 
~Vinod

      reply	other threads:[~2020-02-13 14:46 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-13  0:37 [PATCH] dmaengine: bcm-sba-raid: Replace zero-length array with flexible-array member Gustavo A. R. Silva
2020-02-13 14:46 ` Vinod Koul [this message]

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