[PATCH] dma-direct: Set SG_DMA_SWIOTLB flag for dma-direct

From: T.J. Mercier
Date: Fri May 03 2024 - 14:37:30 EST


As of commit 861370f49ce4 ("iommu/dma: force bouncing if the size is
not cacheline-aligned") sg_dma_mark_swiotlb is called when
dma_map_sgtable takes the IOMMU path and uses SWIOTLB for some portion
of a scatterlist. It is never set for the direct path, so drivers
cannot always rely on sg_dma_is_swiotlb to return correctly after
calling dma_map_sgtable. Fix this by calling sg_dma_mark_swiotlb in the
direct path like it is in the IOMMU path.

Signed-off-by: T.J. Mercier <tjmercier@xxxxxxxxxx>
---
kernel/dma/direct.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 4d543b1e9d57..52f0dcb25ca2 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -12,7 +12,7 @@
#include <linux/pfn.h>
#include <linux/vmalloc.h>
#include <linux/set_memory.h>
-#include <linux/slab.h>
+#include <linux/swiotlb.h>
#include "direct.h"

/*
@@ -497,6 +497,8 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
goto out_unmap;
}
sg_dma_len(sg) = sg->length;
+ if (is_swiotlb_buffer(dev, dma_to_phys(dev, sg->dma_address)))
+ sg_dma_mark_swiotlb(sg);
}

return nents;
--
2.45.0.rc1.225.g2a3ae87e7f-goog