On 27/05/2021 00:45, Frederic Barrat wrote:
This reverts commit 3c0468d4451eb6b4f6604370639f163f9637a479.
That commit was breaking alignment guarantees for the DMA address when
allocating coherent mappings, as described in
Documentation/core-api/dma-api-howto.rst
It was also noticed by Mellanox' driver:
[ 1515.763621] mlx5_core c002:01:00.0: mlx5_frag_buf_alloc_node:146:(pid 13402): unexpected map alignment: 0x0800000000c61000, page_shift=16
[ 1515.763635] mlx5_core c002:01:00.0: mlx5_cqwq_create:181:(pid
13402): mlx5_frag_buf_alloc_node() failed, -12
Signed-off-by: Frederic Barrat <redacted>
Should it be
Fixes: 3c0468d4451e ("powerpc/kernel/iommu: Align size for IOMMU_PAGE_SIZE() to save TCEs")
?
Anyway,
Reviewed-by: Alexey Kardashevskiy <redacted>
I should have known better in the first place, sorry :-/ Thanks,
quoted hunk ↗ jump to hunk
---
arch/powerpc/kernel/iommu.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 57d6b85e9b96..2af89a5e379f 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -898,7 +898,6 @@ void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl,
unsigned int order;
unsigned int nio_pages, io_order;
struct page *page;
- size_t size_io = size;
size = PAGE_ALIGN(size);
order = get_order(size);
@@ -925,9 +924,8 @@ void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl,
memset(ret, 0, size);
/* Set up tces to cover the allocated range */
- size_io = IOMMU_PAGE_ALIGN(size_io, tbl);
- nio_pages = size_io >> tbl->it_page_shift;
- io_order = get_iommu_order(size_io, tbl);
+ nio_pages = size >> tbl->it_page_shift;
+ io_order = get_iommu_order(size, tbl);
mapping = iommu_alloc(dev, tbl, ret, nio_pages, DMA_BIDIRECTIONAL,
mask >> tbl->it_page_shift, io_order, 0);
if (mapping == DMA_MAPPING_ERROR) {@@ -942,9 +940,10 @@ void iommu_free_coherent(struct iommu_table *tbl, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
if (tbl) {
- size_t size_io = IOMMU_PAGE_ALIGN(size, tbl);
- unsigned int nio_pages = size_io >> tbl->it_page_shift;
+ unsigned int nio_pages;
+ size = PAGE_ALIGN(size);
+ nio_pages = size >> tbl->it_page_shift;
iommu_free(tbl, dma_handle, nio_pages);
size = PAGE_ALIGN(size);
free_pages((unsigned long)vaddr, get_order(size));
--
Alexey