Re: [PATCH v2 7/7] dmaengine: idxd: Refactor remove call with idxd_cleanup() helper

[Shuai Xue <xueshuai@linux.alibaba.com>]

在 2025/2/19 21:28, Shuai Xue 写道:
> 
> 
> 在 2025/2/19 05:01, Fenghua Yu 写道:
>> Hi, Shuai,
>>
>> On 2/14/25 21:44, Shuai Xue wrote:
>>> The idxd_cleanup() helper clean up perfmon, interrupts, internals and so
>>
>> s/clean/cleans/
>>
>>
>>> on. Refactor remove call with idxd_cleanup() helper to avoid code
>> s/idxd_cleanup()/the idxd_cleanup()/
>>> duplication. Note, this also fixes the missing put_device() for idxd
>>> groups, enginces and wqs.
>>>
>>> Fixes: bfe1d56091c1 ("dmaengine: idxd: Init and probe for Intel data accelerators")
>>> Suggested-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
>>> Signed-off-by: Shuai Xue <xueshuai@linux.alibaba.com>
>>> ---
>>>   drivers/dma/idxd/init.c | 13 ++-----------
>>>   1 file changed, 2 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
>>> index f40f1c44a302..0fbfbe024c29 100644
>>> --- a/drivers/dma/idxd/init.c
>>> +++ b/drivers/dma/idxd/init.c
>>> @@ -1282,20 +1282,11 @@ static void idxd_remove(struct pci_dev *pdev)
>>>       get_device(idxd_confdev(idxd));
>> get_device() is called here.
>>>       device_unregister(idxd_confdev(idxd));
>>>       idxd_shutdown(pdev);
>>> -    if (device_pasid_enabled(idxd))
>>> -        idxd_disable_system_pasid(idxd);
>>>       idxd_device_remove_debugfs(idxd);
>>> -
>>> -    irq_entry = idxd_get_ie(idxd, 0);
>>> -    free_irq(irq_entry->vector, irq_entry);
>>> -    pci_free_irq_vectors(pdev);
>>> +    idxd_cleanup(idxd);
>>>       pci_iounmap(pdev, idxd->reg_base);
>>> -    if (device_user_pasid_enabled(idxd))
>>> -        idxd_disable_sva(pdev);
>>> -    pci_disable_device(pdev);
>>> -    destroy_workqueue(idxd->wq);
>>> -    perfmon_pmu_remove(idxd);
>>>       idxd_free(idxd);
>>
>> put_device() is called inside idxd_free(). Seems not easy to read code to match the pair.
> 
> IMHO, idxd_free() is paired with idxd_alloc() which grap a reference count by
> device_initialize(). So, we should match that right pair.
> 
>> * When ->release() is called for the idxd->conf_dev, it frees all the memory related
>> * to the idxd context.
> 
> I did not figure out why you explictly grab reference count of
> idxd_confdev(idxd).
> 
> idxd_unregister_devices() is paired with idxd_register_devices(), it only
> decrease reference through wqs, engines, and groups. So a refcnt of
> idxd->conf_dev is still hold by idxd_alloc().
> 
> Please correct me, if I missed anything.
> 
>>
>> Plus idxd_free() is called only in non FLR case.
>>
>> Maybe it's better to change this code to:
>>
>> 1. call put_device() outside idxd_free() so that it's easy to match the get_device() and put_deivce in the same level of function.
> 
> See my comments above.
>>
>> 2. idxd_free() called here is OK because this is not in FLR handler. But only call it in non FLR path in idxd_pci_probe_alloc()
>>
> 
> Exactly, so, shoud I add a protection in idxd_free() in a fact that non FLR case will not call it.
> 
> Thanks.
> Shuai

Hi, all，

Any feedback?

Thanks.
Shuai