From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: "Christian König" <ckoenig.leichtzumerken@gmail.com>
Cc: mojha@codeaurora.org, jkosina@suse.cz, cezary.rojewski@intel.com,
neilb@suse.com, b00073877@aus.edu, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] list: add more extensive double add check
Date: Mon, 1 Feb 2021 18:09:45 +0200 [thread overview]
Message-ID: <YBgnyWrp16WB1JGQ@smile.fi.intel.com> (raw)
In-Reply-To: <YBgnY8FXpHJdoDos@smile.fi.intel.com>
On Mon, Feb 01, 2021 at 06:08:03PM +0200, Andy Shevchenko wrote:
> On Mon, Feb 01, 2021 at 02:52:51PM +0100, Christian König wrote:
> > Adding the same element to a linked list multiple times
> > seems to be a rather common programming mistake. To debug
> > those I've more than once written some code to check a
> > linked list for duplicates.
> >
> > Since re-inventing the wheel over and over again is a bad
> > idea this patch tries to add some common code which allows
> > to check linked lists for duplicates while adding new
> > elements.
> >
> > When list debugging is enabled we currently already check
> > the previous and next element if they are identical to the
> > new one. This patch now adds a configuration option to
> > check N elements before and after the desired position.
> >
> > By default we still only test one item since testing more
> > means quite a large CPU overhead. This can be overwritten
> > on a per C file bases by defining DEBUG_LIST_DOUBLE_ADD
> > before including list.h.
>
> I'm not sure it is a good idea. Currently the implementation is *generic*.
> You are customizing it w/o letting caller know.
>
> Create a derivative implementation and name it exlist (exclusive list) and use
> whenever it makes sense.
And make depth is a runtime parameter available for user.
> And I think if you are still pushing to modify generic one the default must be
> 0 in order not altering current behaviour.
>
> > A new kunit test is also added to the existing list tests
> > which intentionally triggers the debug functionality.
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2021-02-01 16:11 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-01 13:52 [PATCH] list: add more extensive double add check Christian König
2021-02-01 16:08 ` Andy Shevchenko
2021-02-01 16:09 ` Andy Shevchenko [this message]
2021-02-01 22:16 ` NeilBrown
2021-02-02 12:59 ` Christian König
2021-02-04 7:25 ` [list] b9dc2e0952: WARNING:at_lib/list_debug.c:#__list_add_valid kernel test robot
2021-02-04 7:25 ` kernel test robot
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