On 2018-09-25 12:31 p.m., Bart Van Assche wrote:
> On Tue, 2018-09-25 at 12:15 -0600, Logan Gunthorpe wrote:
>> On 2018-09-25 11:29 a.m., Bart Van Assche wrote:
>>> On Tue, 2018-09-25 at 10:22 -0600, Logan Gunthorpe wrote:
>>>> @@ -83,9 +132,14 @@ static int pci_p2pdma_setup(struct pci_dev *pdev)
>>>>
>>>> pdev->p2pdma = p2p;
>>>>
>>>> + error = sysfs_create_group(&pdev->dev.kobj, &p2pmem_group);
>>>> + if (error)
>>>> + goto out_pool_destroy;
>>>> +
>>>> return 0;
>>>>
>>>> out_pool_destroy:
>>>> + pdev->p2pdma = NULL;
>>>> gen_pool_destroy(p2p->pool);
>>>> out:
>>>> devm_kfree(&pdev->dev, p2p);
>>>
>>> This doesn't look right to me. Shouldn't devm_remove_action() be called
>>> instead
>>> of devm_kfree() if sysfs_create_group() fails?
>>
>> That makes no sense to me. We are reversing a devm_kzalloc() not a
>> custom action....
>
> In case what I wrote was not clear: both devm_kzalloc() and
> devm_add_action_or_reset() have to be reversed if sysfs_create_group() fails.
> devm_add_action_or_reset() calls devres_add(). The latter function adds an
> element to the dev->devres_head list. So I think that only calling
> devm_kfree()
> if sysfs_create_group() fails will lead to corruption of the dev->devres_head
> list.
I don't see how it would corrupt the list. devres_remove() uses
list_del_init() which doesn't require that you only remove the tail from
the list... The way I read the code, you can remove any devm action at
any time.
Logan
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