From: Haavard Skinnemoen <hskinnemoen@atmel.com>
To: Shannon Nelson <shannon.nelson@intel.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
shannon.nelson@intel.com, greg@kroah.com,
dan.j.williams@intel.com
Subject: Re: [PATCH] DMAENGINE: too many kref_put calls
Date: Sat, 27 Oct 2007 15:28:16 +0200 [thread overview]
Message-ID: <20071027152816.2d447c70@siona> (raw)
In-Reply-To: <20071026235648.5737.45405.stgit@localhost.localdomain>
On Fri, 26 Oct 2007 16:56:48 -0700
Shannon Nelson <shannon.nelson@intel.com> wrote:
> @@ -134,8 +134,7 @@ static void dma_async_device_cleanup(struct kref
> *kref);
> static void dma_dev_release(struct device *dev)
> {
> - struct dma_chan *chan = to_dma_chan(dev);
> - kref_put(&chan->device->refcount, dma_async_device_cleanup);
> + return;
> }
Hmm...what prevents dma_chan_cleanup() from being called while someone
still holds a reference to the "class" device? This will allow the
module removal to proceed, the device to be freed, and things will blow
up...
I think my patch is better. By taking two references, the order in
which the cleanup functions are called doesn't matter -- both have to
complete before the module removal is allowed to proceed.
Håvard
prev parent reply other threads:[~2007-10-27 13:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-26 23:56 [PATCH] DMAENGINE: too many kref_put calls Shannon Nelson
2007-10-27 6:40 ` Al Viro
2007-10-27 13:28 ` Haavard Skinnemoen [this message]
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