Subject: Re: linux-next: manual merge of the dmaengine tree with Linus' tree

From: Dave Jiang <[email-masked]>
Date: Wed, 18 May 2022 10:20:59 -0700

On 5/18/2022 4:46 AM, Vinod Koul wrote:
> On 17-05-22, 15:34, Stephen Rothwell wrote:
>> Hi all,
>>
>> Today's linux-next merge of the dmaengine tree got a conflict in:
>>
>>    drivers/dma/idxd/device.c
>>
>> between commit:
>>
>>    1cd8e751d96c ("dmaengine: idxd: skip clearing device context when device is read-only")
>>
>> from Linus' tree and commit:
>>
>>    cf4ac3fef338 ("dmaengine: idxd: fix lockdep warning on device driver removal")
> Thank you Stephen, the merge looks right to me. Dave pls verify and test
> -next
>
>> from the dmaengine tree.
>>
>> I fixed it up (see below) and can carry the fix as necessary. This
>> is now fixed as far as linux-next is concerned, but any non trivial
>> conflicts should be mentioned to your upstream maintainer when your tree
>> is submitted for merging.  You may also want to consider cooperating
>> with the maintainer of the conflicting tree to minimise any particularly
>> complex conflicts.
>>
>> -- 
>> Cheers,
>> Stephen Rothwell
>>
>> diff --cc drivers/dma/idxd/device.c
>> index f652da6ab47d,1143886f4a80..000000000000
>> --- a/drivers/dma/idxd/device.c
>> +++ b/drivers/dma/idxd/device.c
>> @@@ -699,21 -716,23 +716,26 @@@ static void idxd_device_wqs_clear_state
>>    		struct idxd_wq *wq = idxd->wqs[i];
>>    
>>    		if (wq->state == IDXD_WQ_ENABLED) {
>> + 			mutex_lock(&wq->wq_lock);
>>    			idxd_wq_disable_cleanup(wq);
>>   -			idxd_wq_device_reset_cleanup(wq);
>>    			wq->state = IDXD_WQ_DISABLED;
>> + 			mutex_unlock(&wq->wq_lock);
>>    		}
>>   +		idxd_wq_device_reset_cleanup(wq);

The lock needs to go around both functions, we can move it outside the 
if().

  + 		mutex_lock(&wq->wq_lock);
   		if (wq->state == IDXD_WQ_ENABLED) {
   			idxd_wq_disable_cleanup(wq);
  -			idxd_wq_device_reset_cleanup(wq);
   			wq->state = IDXD_WQ_DISABLED;
   		}
  +		idxd_wq_device_reset_cleanup(wq);
  + 		mutex_unlock(&wq->wq_lock);

>>    	}
>>    }
>>    
>>    void idxd_device_clear_state(struct idxd_device *idxd)
>>    {
>>   +	if (!test_bit(IDXD_FLAG_CONFIGURABLE, &idxd->flags))
>>   +		return;
>>   +
>> + 	idxd_device_wqs_clear_state(idxd);
>> + 	spin_lock(&idxd->dev_lock);
>>    	idxd_groups_clear_state(idxd);
>>    	idxd_engines_clear_state(idxd);
>> - 	idxd_device_wqs_clear_state(idxd);
>> + 	idxd->state = IDXD_DEV_DISABLED;
>> + 	spin_unlock(&idxd->dev_lock);
>>    }
>>    
>>    static void idxd_group_config_write(struct idxd_group *group)
>
>