linux-kernel - Re: [PATCH RESEND v2 04/10] dmaengine: idxd: Flush kernel workqueues on Function Level Reset

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Message-ID: <87v7h16nql.fsf@intel.com>
Date: Fri, 16 Jan 2026 17:18:10 -0800
From: Vinicius Costa Gomes <vinicius.gomes@...el.com>
To: Dave Jiang <dave.jiang@...el.com>, Vinod Koul <vkoul@...nel.org>, Dan
 Williams <dan.j.williams@...el.com>
Cc: dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND v2 04/10] dmaengine: idxd: Flush kernel
 workqueues on Function Level Reset

Dave Jiang <dave.jiang@...el.com> writes:

> On 1/15/26 3:47 PM, Vinicius Costa Gomes wrote:
>> When a Function Level Reset (FLR) happens, terminate the pending
>> descriptors that were issued by in-kernel users and disable the
>> interrupts associated with those. They will be re-enabled after FLR
>> finishes.
>> 
>> idxd_wq_flush_desc() is declared on idxd.h because it's going to be
>> used in by the DMA backend in a future patch.
>> 
>> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@...el.com>
>> ---
>>  drivers/dma/idxd/device.c | 20 ++++++++++++++++++++
>>  drivers/dma/idxd/idxd.h   |  1 +
>>  drivers/dma/idxd/irq.c    | 16 ++++++++++++++++
>>  3 files changed, 37 insertions(+)
>> 
>> diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
>> index 5265925f3076..b8422dc7d2ca 100644
>> --- a/drivers/dma/idxd/device.c
>> +++ b/drivers/dma/idxd/device.c
>> @@ -1339,6 +1339,11 @@ void idxd_wq_free_irq(struct idxd_wq *wq)
>>  
>>  	free_irq(ie->vector, ie);
>>  	idxd_flush_pending_descs(ie);
>> +
>> +	/* The interrupt might have been already released by FLR */
>> +	if (ie->int_handle == INVALID_INT_HANDLE)
>> +		return;
>> +
>>  	if (idxd->request_int_handles)
>>  		idxd_device_release_int_handle(idxd, ie->int_handle, IDXD_IRQ_MSIX);
>>  	idxd_device_clear_perm_entry(idxd, ie);
>> @@ -1347,6 +1352,21 @@ void idxd_wq_free_irq(struct idxd_wq *wq)
>>  	ie->pasid = IOMMU_PASID_INVALID;
>>  }
>>  
>> +void idxd_wq_flush_descs(struct idxd_wq *wq)
>> +{
>> +	struct idxd_irq_entry *ie = &wq->ie;
>> +	struct idxd_device *idxd = wq->idxd;
>> +
> Should it take a wq lock for this function?
>

Good catch. Will take a another look and see if I am missing any locks
elsewhere.


Cheers,
-- 
Vinicius