Merge tag 'dma-mapping-4.20-3' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fixes from Christoph Hellwig:
"Two dma-direct / swiotlb regressions fixes:
- zero is a valid physical address on some arm boards, we can't use
it as the error value
- don't try to cache flush the error return value (no matter what it
is)"
* tag 'dma-mapping-4.20-3' of git://git.infradead.org/users/hch/dma-mapping:
swiotlb: Skip cache maintenance on map error
dma-direct: Make DIRECT_MAPPING_ERROR viable for SWIOTLB
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index bd73e7a..9e66bfe 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -5,7 +5,7 @@
#include <linux/dma-mapping.h>
#include <linux/mem_encrypt.h>
-#define DIRECT_MAPPING_ERROR 0
+#define DIRECT_MAPPING_ERROR (~(dma_addr_t)0)
#ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
#include <asm/dma-direct.h>
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 5731daa..045930e 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -679,7 +679,8 @@
}
if (!dev_is_dma_coherent(dev) &&
- (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0)
+ (attrs & DMA_ATTR_SKIP_CPU_SYNC) == 0 &&
+ dev_addr != DIRECT_MAPPING_ERROR)
arch_sync_dma_for_device(dev, phys, size, dir);
return dev_addr;
