On Mon, Mar 16, 2009 at 7:20 PM, Atsushi Nemoto <anemo@xxxxxxxxxxxxx> wrote:
> On Mon, 16 Mar 2009 14:50:46 -0700, Dan Williams <dan.j.williams@xxxxxxxxx> wrote:
>> > And above "continue" looks buggy anyway. Keeping incomplete channels
>> > in device->channels list looks very dangerous...
>>
>> Yes it does. Here is the proposed fix:
>> ----->
>> dmaengine: fail device registration if channel registration fails
>>
>> From: Dan Williams <dan.j.williams@xxxxxxxxx>
>>
>> Atsushi points out:
>> "If alloc_percpu or kzalloc failed, chan_id does not match with its
>> position in device->channels list.
>>
>> And above "continue" looks buggy anyway. Keeping incomplete channels
>> in device->channels list looks very dangerous..."
>>
>> Reported-by: Atsushi Nemoto <anemo@xxxxxxxxxxxxx>
>> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
>
> Thanks, but it seems a hole sill exists. If alloc_percpu or kzalloc
> for the first channel failed, when idr_ref will be freed ?
>
True, we need a check like the following:
/* if we never registered a channel just release the idr */
if (atomic_read(idr_ref) == 0) {
mutex_lock(&dma_list_mutex);
idr_remove(&dma_idr, device->dev_id);
mutex_unlock(&dma_list_mutex);
kfree(idr_ref);
return rc;
}
> Hmm.. why idr_ref is dynamically allocated? Just putting it in
> dma_device makes thing more simple, no?
>
The sysfs device has a longer lifetime than dma_device. See commit
41d5e59c [1].
--
Dan
[1] http://git.kernel.org/?p=linux/kernel/git/djbw/async_tx.git;a=commitdiff;h=41d5e59c
> ---
> Atsushi Nemoto
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