[RFC PATCH 3/3] riscv: use VA+PA variant of CMO macros for DMA page preparation

[Icenowy Zheng]

When doing DMA page preparation, both the VA and the PA are easily
accessible from struct page.

Use the alternative macro variant that takes both VA and PA as
parameters, thus in case the ISA extension used support PA directly, the
overhead for re-converting VA to PA can be omitted.

Suggested-by: Guo Ren <guoren at kernel.org>
Signed-off-by: Icenowy Zheng <uwu at icenowy.me>
---
 arch/riscv/mm/dma-noncoherent.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
index a751f4aece62..0ad0614d1ad4 100644
--- a/arch/riscv/mm/dma-noncoherent.c
+++ b/arch/riscv/mm/dma-noncoherent.c
@@ -52,8 +52,9 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 void arch_dma_prep_coherent(struct page *page, size_t size)
 {
 	void *flush_addr = page_address(page);
+	phys_addr_t paddr = PFN_PHYS(page_to_pfn(page));
 
-	ALT_CMO_OP(flush, flush_addr, size, riscv_cbom_block_size);
+	ALT_CMO_OP_VPA(flush, flush_addr, paddr, size, riscv_cbom_block_size);
 }
 
 void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
-- 
2.38.1