Re: [PATCH v2] dmaengine: idxd: force wq context cleanup on device disable path

[Fenghua Yu <fenghua.yu@intel.com>]

On Wed, Jun 15, 2022 at 04:42:19PM -0700, Fenghua Yu wrote:
> From: Dave Jiang <dave.jiang@intel.com>
> 
> Testing shown that when a wq mode is setup to be dedicated and then torn
> down and reconfigured to shared, the wq configured end up being dedicated
> anyays. The root cause is when idxd_device_wqs_clear_state() gets called
> during idxd_driver removal, idxd_wq_disable_cleanup() does not get called
> vs when the wq driver is removed first. The check of wq state being
> "enabled" causes the cleanup to be bypassed. However, idxd_driver->remove()
> releases all wq drivers. So the wqs goes to "disabled" state and will never
> be "enabled". By that point, the driver has no idea if the wq was
> previously configured or clean. So force call idxd_wq_disable_cleanup() on
> all wqs always to make sure everything gets cleaned up.
> 
> Reported-by: Tony Zhu <tony.zhu@intel.com>
> Tested-by: Tony Zhu <tony.zhu@intel.com>
> Fixes: 0dcfe41e9a4c ("dmanegine: idxd: cleanup all device related bits after disabling device")
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>

> ---
> Change Log:
> v2:
> - Re-based to 5.19-rc2 so that it can be applied cleanly. No functionality
>   change.
> 
> v1:
> https://patchwork.kernel.org/project/linux-dmaengine/patch/165090959239.1376825.18183942742142655091.stgit@djiang5-desk3.ch.intel.com/
> 
>  drivers/dma/idxd/device.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/drivers/dma/idxd/device.c b/drivers/dma/idxd/device.c
> index ff0ea60051f0..5a8cc52c1abf 100644
> --- a/drivers/dma/idxd/device.c
> +++ b/drivers/dma/idxd/device.c
> @@ -716,10 +716,7 @@ static void idxd_device_wqs_clear_state(struct idxd_device *idxd)
>  		struct idxd_wq *wq = idxd->wqs[i];
>  
>  		mutex_lock(&wq->wq_lock);
> -		if (wq->state == IDXD_WQ_ENABLED) {
> -			idxd_wq_disable_cleanup(wq);
> -			wq->state = IDXD_WQ_DISABLED;
> -		}
> +		idxd_wq_disable_cleanup(wq);
>  		idxd_wq_device_reset_cleanup(wq);
>  		mutex_unlock(&wq->wq_lock);
>  	}
> -- 
> 2.32.0
>