linux-kernel - Re: [PATCH 5/6] dma-mapping: Allow batched DMA sync operations if supported by the arch

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20251225054509.39917-1-21cnbao@gmail.com>
Date: Thu, 25 Dec 2025 18:45:09 +1300
From: Barry Song <21cnbao@...il.com>
To: leon@...nel.org
Cc: 21cnbao@...il.com,
	ada.coupriediaz@....com,
	anshuman.khandual@....com,
	ardb@...nel.org,
	catalin.marinas@....com,
	iommu@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	m.szyprowski@...sung.com,
	maz@...nel.org,
	robin.murphy@....com,
	ryan.roberts@....com,
	surenb@...gle.com,
	v-songbaohua@...o.com,
	will@...nel.org,
	zhengtangquan@...o.com
Subject: Re: [PATCH 5/6] dma-mapping: Allow batched DMA sync operations if supported by the arch

> > >
> >
> > OK. Could you take a look at [1] and see if any further
> > improvements are needed before I send v2?
>
> Everything looks ok, except these renames:
> -                       arch_sync_dma_for_cpu(paddr, sg->length, dir);
> +                       arch_sync_dma_for_cpu_batch_add(paddr, sg->length, dir);

Thanks!
I'm happy to drop the rename as outlined below-feedback welcome :-)

diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
index dd2c8586a725..487fb7c355ed 100644
--- a/arch/arm64/include/asm/cache.h
+++ b/arch/arm64/include/asm/cache.h
@@ -87,6 +87,12 @@ int cache_line_size(void);
 
 #define dma_get_cache_alignment	cache_line_size
 
+static inline void arch_sync_dma_flush(void)
+{
+	dsb(sy);
+}
+#define arch_sync_dma_flush arch_sync_dma_flush
+
 /* Compress a u64 MPIDR value into 32 bits. */
 static inline u64 arch_compact_of_hwid(u64 id)
 {
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index b2b5792b2caa..ae1ae0280eef 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -17,7 +17,7 @@ void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
 {
 	unsigned long start = (unsigned long)phys_to_virt(paddr);
 
-	dcache_clean_poc(start, start + size);
+	dcache_clean_poc_nosync(start, start + size);
 }
 
 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
@@ -28,7 +28,7 @@ void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 	if (dir == DMA_TO_DEVICE)
 		return;
 
-	dcache_inval_poc(start, start + size);
+	dcache_inval_poc_nosync(start, start + size);
 }
 
 void arch_dma_prep_coherent(struct page *page, size_t size)
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index 4809204c674c..e7dd8a63b40e 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -361,6 +361,12 @@ static inline void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
 }
 #endif /* ARCH_HAS_SYNC_DMA_FOR_CPU */
 
+#ifndef arch_sync_dma_flush
+static inline void arch_sync_dma_flush(void)
+{
+}
+#endif
+
 #ifdef CONFIG_ARCH_HAS_SYNC_DMA_FOR_CPU_ALL
 void arch_sync_dma_for_cpu_all(void);
 #else