>-----Original Message----- >From: Intel-gfx <intel-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of >Matthew Auld >Sent: Thursday, October 27, 2022 11:27 AM >To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx >Subject: [PATCH 1/2] drm/i915/dmabuf: fix sg_table handling in >map_dma_buf > >We need to iterate over the original entries here for the sg_table, >pulling out the struct page for each one, to be remapped. However >currently this incorrectly iterates over the final dma mapped entries, >which is likely just one gigantic sg entry if the iommu is enabled, >leading to us only mapping the first struct page (and any physically >contiguous pages following it), even if there is potentially lots more >data to follow. > >Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/7306 >Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx> >Cc: Lionel Landwerlin <lionel.g.landwerlin@xxxxxxxxx> >Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx> >Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> >--- > drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > >diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c >b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c >index 07eee1c09aaf..05ebbdfd3b3b 100644 >--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c >+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c >@@ -40,13 +40,13 @@ static struct sg_table *i915_gem_map_dma_buf(struct >dma_buf_attachment *attachme > goto err; > } > >- ret = sg_alloc_table(st, obj->mm.pages->nents, GFP_KERNEL); >+ ret = sg_alloc_table(st, obj->mm.pages->orig_nents, GFP_KERNEL); > if (ret) > goto err_free; > > src = obj->mm.pages->sgl; > dst = st->sgl; >- for (i = 0; i < obj->mm.pages->nents; i++) { >+ for (i = 0; i < obj->mm.pages->orig_nents; i++) { This really should use the for_each_sg() macro. I proposed a clean up patch a while back that looked like this: diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c index e2cdc2640c08..ccc5d46aa749 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c @@ -7,6 +7,7 @@ #include <linux/dma-buf.h> #include <linux/highmem.h> #include <linux/dma-resv.h> +#include <linux/scatterlist.h> #include "gem/i915_gem_dmabuf.h" #include "i915_drv.h" @@ -41,12 +42,10 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attach, if (ret) goto err_free; - src = obj->mm.pages->sgl; dst = sgt->sgl; - for (i = 0; i < obj->mm.pages->nents; i++) { + for_each_sg(obj->mm.pages->sgl, src, obj->mm.pages->nents, i) { sg_set_page(dst, sg_page(src), src->length, 0); dst = sg_next(dst); - src = sg_next(src); } If you are updating the for loop, this might be a reasonable update as well. Mike > sg_set_page(dst, sg_page(src), src->length, 0); > dst = sg_next(dst); > src = sg_next(src); >-- >2.37.3
