linux-kernel - Re: [PATCH 1/4] container_of: add container_of_const() that preserves const-ness of the pointer

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Date:   Thu, 1 Dec 2022 23:21:50 +0000
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, Jason Gunthorpe <jgg@...pe.ca>,
        Matthew Wilcox <willy@...radead.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH 1/4] container_of: add container_of_const() that
 preserves const-ness of the pointer

Hi Greg,

On Thu, Dec 01, 2022 at 08:30:54PM +0100, Greg Kroah-Hartman wrote:
> container_of does not preserve the const-ness of a pointer that is
> passed into it, which can cause C code that passes in a const pointer to
> get a pointer back that is not const and then scribble all over the data
> in it.  To prevent this, container_of_const() will preserve the const
> status of the pointer passed into it using the newly available _Generic()
> method.

"_const" in the name suggests that the macro would always take a const
argument. Could this be called e.g. container_of_safe() (for type-safe, but
full type_safe would be a bit long)?

-- 
Kind regards,

Sakari Ailus