2020-09-22 20:59:33

by Logan Gunthorpe

Subject: [PATCH] dmaengine: ioat: Allocate correct size for descriptor chunk

dma_alloc_coherent() is called with a fixed SZ_2M size, but frees happen
with IOAT_CHUNK_SIZE. Recently, IOAT_CHUNK_SIZE was reduced to 512M but
the allocation did not change. To fix, change to using the
IOAT_CHUNK_SIZE define.

This was caught with the upcoming patchset for converting Intel platforms to the
dma-iommu implementation. It has a warning when the unmapped size differs from
the mapped size.

Fixes: a02254f8a676 ("dmaengine: ioat: Decreasing allocation chunk size 2M->512K")
Link: https://lore.kernel.org/intel-gfx/[email protected]/
Suggested-by: Robin Murphy <[email protected]>
Signed-off-by: Logan Gunthorpe <[email protected]>
Cc: Vinod Koul <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: Dan Williams <[email protected]>
---
drivers/dma/ioat/dma.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index a814b200299b..07296171e2bb 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -389,7 +389,7 @@ ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags)
struct ioat_descs *descs = &ioat_chan->descs[i];

descs->virt = dma_alloc_coherent(to_dev(ioat_chan),
- SZ_2M, &descs->hw, flags);
+ IOAT_CHUNK_SIZE, &descs->hw, flags);
if (!descs->virt) {
int idx;


base-commit: ba4f184e126b751d1bffad5897f263108befc780
--
2.20.1

2020-10-05 04:50:25

by Vinod Koul

Subject: Re: [PATCH] dmaengine: ioat: Allocate correct size for descriptor chunk

On 22-09-20, 14:08, Logan Gunthorpe wrote:
> dma_alloc_coherent() is called with a fixed SZ_2M size, but frees happen
> with IOAT_CHUNK_SIZE. Recently, IOAT_CHUNK_SIZE was reduced to 512M but
> the allocation did not change. To fix, change to using the
> IOAT_CHUNK_SIZE define.
>
> This was caught with the upcoming patchset for converting Intel platforms to the
> dma-iommu implementation. It has a warning when the unmapped size differs from
> the mapped size.

Applied, thanks

--
~Vinod