From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Leon Romanovsky <leonro@mellanox.com>
Cc: Zhu Yanjun <yanjun.zhu@oracle.com>,
saeedm@mellanox.com, matanb@mellanox.com, netdev@vger.kernel.org,
linux-rdma@vger.kernel.org, yuval.shaia@oracle.com
Subject: Re: [PATCH 1/2] mlx4: remove unnecessary pci_set_drvdata()
Date: Tue, 15 Aug 2017 11:21:49 -0600 [thread overview]
Message-ID: <20170815172149.GC15171@obsidianresearch.com> (raw)
In-Reply-To: <20170815071336.GL24282@mtr-leonro.local>
On Tue, Aug 15, 2017 at 10:13:36AM +0300, Leon Romanovsky wrote:
> On Tue, Aug 15, 2017 at 02:33:05AM -0400, Zhu Yanjun wrote:
> > The driver core clears the driver data to NULL after device_release
> > or on probe failure. Thus, it is not necessary to manually clear the
> > device driver data to NULL.
> >
>
> It makes sense and I'm pretty sure that you are right, but I'm failing
> to find the function in device core which sets it to NULL. Can you help
> me and present the actual call stack to that code place?
http://elixir.free-electrons.com/linux/v4.13-rc1/source/drivers/base/dd.c#L840
The call to the remove callback is on line 833.
This is done after dropping devres, so you could allocate the drv data
inside a devm object and everything would unwind correctly.
In this case, the kfree is explicit, so I would advocate for still putting
the null near the kfree to minimize the time where a free'd pointer is
present - eg incase a devm callback or some other bug accidently
touches it.
Jason
next prev parent reply other threads:[~2017-08-15 17:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-15 6:33 [PATCH 1/2] mlx4: remove unnecessary pci_set_drvdata() Zhu Yanjun
[not found] ` <1502778786-14738-1-git-send-email-yanjun.zhu-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2017-08-15 6:33 ` [PATCH 2/2] mlx5: " Zhu Yanjun
[not found] ` <1502778786-14738-2-git-send-email-yanjun.zhu-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
2017-08-15 23:47 ` David Miller
2017-08-15 23:46 ` [PATCH 1/2] mlx4: " David Miller
2017-08-15 7:13 ` Leon Romanovsky
2017-08-15 17:21 ` Jason Gunthorpe [this message]
[not found] ` <20170815172149.GC15171-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
2017-08-15 18:00 ` Leon Romanovsky
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