From: Nicolin Chen Date: Tue, 1 Sep 2020 22:16:46 +0000 (-0700) Subject: dma-mapping: set default segment_boundary_mask to ULONG_MAX X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=135ba11a7a07b4ce9197d9fa4b196329a57f1e06;p=linux.git dma-mapping: set default segment_boundary_mask to ULONG_MAX The default segment_boundary_mask was set to DMA_BIT_MAKS(32) a decade ago by referencing SCSI/block subsystem, as a 32-bit mask was good enough for most of the devices. Now more and more drivers set dma_masks above DMA_BIT_MAKS(32) while only a handful of them call dma_set_seg_boundary(). This means that most drivers have a 4GB segmention boundary because DMA API returns a 32-bit default value, though they might not really have such a limit. The default segment_boundary_mask should mean "no limit" since the device doesn't explicitly set the mask. But a 32-bit mask certainly limits those devices capable of 32+ bits addressing. So this patch sets default segment_boundary_mask to ULONG_MAX. Signed-off-by: Nicolin Chen Acked-by: Niklas Schnelle Signed-off-by: Christoph Hellwig --- diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index faab0a8210b90..df0bff2ea750e 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -629,7 +629,7 @@ static inline unsigned long dma_get_seg_boundary(struct device *dev) { if (dev->dma_parms && dev->dma_parms->segment_boundary_mask) return dev->dma_parms->segment_boundary_mask; - return DMA_BIT_MASK(32); + return ULONG_MAX; } /**