RE: [PATCH v9 07/10] iommu/vt-d: Allow qi_submit_sync() to return the QI faults

[Tian, Kevin]

> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Thursday, December 28, 2023 11:06 PM
> 
> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> 
> This allows qi_submit_sync() to return back faults to callers.

this might be useful to add a note that the retry logic itself is being discussed
in a separate thread [1]. Here we keep it intact and just make sure no retry for
the newly added user domain cache invalidation.

[1] https://lore.kernel.org/all/20231228001646.587653-6-haifeng.zhao@xxxxxxxxxxxxxxx/

> 
> -		if (qi->desc_status[wait_index] == QI_ABORT)
> +		if (qi->desc_status[wait_index] == QI_ABORT) {
> +			/*
> +			 * If the caller is interested in the error, no need
> +			 * to retry, just return the time out error to the
> +			 * caller.
> +			 */
> +			if (fsts)
> +				return -ETIMEDOUT;
> +		}
>  			return -EAGAIN;

indent should be adjusted and it changes the original logic which returns
-EAGAIN only if QI_ABORT is set for the wait_index.

the simpler form is:

		/* No need to retry if the caller is interested in the timeout error */
		if (qi->desc_status[wait_index] == QI_ABORT)
			return fsts ? -ETIMEDOUT : -EAGAIN;

otherwise,

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>