6.6-stable review patch. If anyone has any objections, please let me know.
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From: Huacai Chen chenhuacai@loongson.cn
commit 4103cfe9dcb88010ae4911d3ff417457d1b6a720 upstream.
ARCH_DMA_MINALIGN is 1 by default, but some LoongArch-specific devices (such as APBDMA) require 16 bytes alignment. When the data buffer length is too small, the hardware may make an error writing cacheline. Thus, it is dangerous to allocate a small memory buffer for DMA. It's always safe to define ARCH_DMA_MINALIGN as L1_CACHE_BYTES but unnecessary (kmalloc() need small memory objects). Therefore, just increase it to 16.
Cc: stable@vger.kernel.org Tested-by: Binbin Zhou zhoubinbin@loongson.cn Signed-off-by: Huacai Chen chenhuacai@loongson.cn Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/loongarch/include/asm/cache.h | 2 ++ 1 file changed, 2 insertions(+)
--- a/arch/loongarch/include/asm/cache.h +++ b/arch/loongarch/include/asm/cache.h @@ -8,6 +8,8 @@ #define L1_CACHE_SHIFT CONFIG_L1_CACHE_SHIFT #define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT)
+#define ARCH_DMA_MINALIGN (16) + #define __read_mostly __section(".data..read_mostly")
#endif /* _ASM_CACHE_H */