In __iommu_dma_alloc_noncontiguous() the value returned by
iommu_map_sg_atomic() is checked for being smaller than size. Before
commit ad8f36e4b6b1 ("iommu: return full error code from
iommu_map_sg[_atomic]()") this simply checked if the requested size was
successfully mapped.
After that commit iommu_map_sg_atomic() may also return a negative
error value. In principle this too would be covered by the existing
check. There is one problem however, as size is of type size_t while the
return type of iommu_map_sg_atomic() is now of type ssize_t the latter gets
converted to size_t and negative error values end up as very large
positive values making the check succeed. Fix this by making the return
type visible with a local variable and add an explicit cast to ssize_t.
Fixes: ad8f36e4b6b1 ("iommu: return full error code from
iommu_map_sg[_atomic]()")
Cc: sta...@vger.kernel.org
Signed-off-by: Niklas Schnelle <schne...@linux.ibm.com>
---
drivers/iommu/dma-iommu.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 09f6e1c0f9c0..b4fcf1d92994 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -776,6 +776,7 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct
device *dev,
unsigned int count, min_size, alloc_sizes = domain->pgsize_bitmap;
struct page **pages;
dma_addr_t iova;
+ ssize_t mapped;
if (static_branch_unlikely(&iommu_deferred_attach_enabled) &&
iommu_deferred_attach(dev, domain))
@@ -813,8 +814,8 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct
device *dev,
arch_dma_prep_coherent(sg_page(sg), sg->length);
}
- if (iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt->orig_nents, ioprot)
- < size)
+ mapped = iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt->orig_nents,
ioprot);
+ if (mapped < (ssize_t)size)
goto out_free_sg;
sgt->sgl->dma_address = iova;
--
2.32.0
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