Re: [PATCH] iommu/dma: fix incorrect error return on iommu deferred attach

[John Garry]

On 27/10/2021 18:47, Logan Gunthorpe wrote:
> scsi_dma_map() was reporting a failure during boot on an AMD machine
> with the IOMMU enabled.
>
>    scsi_dma_map failed: request for 36 bytes!
>
> The issue was tracked down to a mistake in logic: should not return
> an error if iommu_deferred_attach() returns zero.
>
> Reported-by: Marshall Midden<marshallmidden@xxxxxxxxx>
> Fixes: dabb16f67215 ("iommu/dma: return error code from iommu_dma_map_sg()")
> Link:https://lore.kernel.org/all/CAD2CkAWjS8=kKwEEN4cgVNjyFORUibzEiCUA-X+SMtbo0JoMmA@xxxxxxxxxxxxxx
> Signed-off-by: Logan Gunthorpe<logang@xxxxxxxxxxxx>
> Cc: Joerg Roedel<joro@xxxxxxxxxx>
> Cc: Will Deacon<will@xxxxxxxxxx>

Seems reasonable, FWIW:
Reviewed-by: John Garry <john.garry@xxxxxxxxxx>