On 2023-05-31 16:48, Catalin Marinas wrote:
[...]
diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
index 2f06178996ba..69d87e312263 100644
--- a/include/linux/scatterlist.h
+++ b/include/linux/scatterlist.h
@@ -251,11 +251,13 @@ static inline void sg_unmark_end(struct scatterlist *sg)
/*
* One 64-bit architectures there is a 4-byte padding in struct scatterlist
* (assuming also CONFIG_NEED_SG_DMA_LENGTH is set). Use this padding for DMA
- * flags bits to indicate when a specific dma address is a bus address.
+ * flags bits to indicate when a specific dma address is a bus address or the
+ * buffer may have been bounced via SWIOTLB.
*/
#ifdef CONFIG_NEED_SG_DMA_FLAGS
-#define SG_DMA_BUS_ADDRESS (1 << 0)
+#define SG_DMA_BUS_ADDRESS (1 << 0)
+#define SG_DMA_SWIOTLB (1 << 1)
/**
* sg_dma_is_bus_address - Return whether a given segment was marked
@@ -298,6 +300,34 @@ static inline void sg_dma_unmark_bus_address(struct scatterlist *sg)
sg->dma_flags &= ~SG_DMA_BUS_ADDRESS;
}
+/**
+ * sg_dma_use_swiotlb - Return whether the scatterlist was marked for SWIOTLB
+ * bouncing
+ * @sg: SG entry
+ *
+ * Description:
+ * Returns true if the scatterlist was marked for SWIOTLB bouncing. Not all
+ * elements may have been bounced, so the caller would have to check
+ * individual SG entries with is_swiotlb_buffer().
+ */
+static inline bool sg_dma_use_swiotlb(struct scatterlist *sg)
Nit: since you tweaked the flag name again, we could happily go back to
the pattern with s/use/is/ for this one now too.
+{
+ return sg->dma_flags & SG_DMA_SWIOTLB;
+}
+
+/**
+ * sg_dma_use_swiotlb - Mark the scatterlist for SWIOTLB bouncing
Oops - s/use/mark/
Feel free to fix those up when applying if there's no other reason for a v7.
Thanks,
Robin.
+ * @sg: SG entry
+ *
+ * Description:
+ * Marks a a scatterlist for SWIOTLB bounce. Not all SG entries may be
+ * bounced.
+ */
+static inline void sg_dma_mark_swiotlb(struct scatterlist *sg)
+{
+ sg->dma_flags |= SG_DMA_SWIOTLB;
+}
+
#else
static inline bool sg_dma_is_bus_address(struct scatterlist *sg)
@@ -310,6 +340,13 @@ static inline void sg_dma_mark_bus_address(struct scatterlist *sg)
static inline void sg_dma_unmark_bus_address(struct scatterlist *sg)
{
}
+static inline bool sg_dma_use_swiotlb(struct scatterlist *sg)
+{
+ return false;
+}
+static inline void sg_dma_mark_swiotlb(struct scatterlist *sg)
+{
+}
#endif /* CONFIG_NEED_SG_DMA_FLAGS */
