Hi,
On 27/08/2020 22:36, Logan Gunthorpe wrote:
On 2020-08-23 6:04 p.m., Tom Murphy wrote:
I have added a check for the sg_dma_len == 0 : """ } __sgt_iter(struct scatterlist *sgl, bool dma) { struct sgt_iter s = { .sgp = sgl };
if (sgl && sg_dma_len(sgl) == 0)s.sgp = NULL; if (s.sgp) { .....""" at location [1]. but it doens't fix the problem.
Based on my read of the code, it looks like we also need to change usage of sgl->length... Something like the rough patch below, maybe?
This thread was brought to my attention and I initially missed this reply. Essentially I came to the same conclusion about the need to use sg_dma_len. One small correction below:
Also, Tom, do you have an updated version of the patchset to convert the Intel IOMMU to dma-iommu available? The last one I've found doesn't apply cleanly (I'm assuming parts of it have been merged in slightly modified forms).
Thanks,
Logan
--
diff --git a/drivers/gpu/drm/i915/i915_scatterlist.h b/drivers/gpu/drm/i915/i915 index b7b59328cb76..9367ac801f0c 100644 --- a/drivers/gpu/drm/i915/i915_scatterlist.h +++ b/drivers/gpu/drm/i915/i915_scatterlist.h @@ -27,13 +27,19 @@ static __always_inline struct sgt_iter { } __sgt_iter(struct scatterlist *sgl, bool dma) { struct sgt_iter s = { .sgp = sgl };
if (sgl && !sg_dma_len(s.sgp))
I'd extend the condition to be, just to be safe:
if (dma && sgl && !sg_dma_len(s.sgp))
s.sgp = NULL;if (s.sgp) { s.max = s.curr = s.sgp->offset;
s.max += s.sgp->length;if (dma)
if (dma) {s.max += sg_dma_len(s.sgp); s.dma = sg_dma_address(s.sgp);
else
} else {s.max += s.sgp->length; s.pfn = page_to_pfn(sg_page(s.sgp));}
Otherwise has this been tested or alternatively how to test it? (How to repro the issue.)
Regards,
Tvrtko