[PATCH 5.11 13/31] driver core: add a min_align_mask field to struct device_dma_parameters

Greg Kroah-Hartman
2021-05-05T12:11:38Z

From: Jianxiong Gao <jxgao@google.com>

commit: 36950f2da1ea4cb683be174f6f581e25b2d33e71

Some devices rely on the address offset in a page to function
correctly (NVMe driver as an example). These devices may use
a different page size than the Linux kernel. The address offset
has to be preserved upon mapping, and in order to do so, we
need to record the page_offset_mask first.

Signed-off-by: Jianxiong Gao <jxgao@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/device.h | 1 +
include/linux/dma-mapping.h | 16 ++++++++++++++++
2 files changed, 17 insertions(+)

--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -291,6 +291,7 @@ struct device_dma_parameters {
* sg limitations.
*/
unsigned int max_segment_size;
+ unsigned int min_align_mask;
unsigned long segment_boundary_mask;
};

--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -500,6 +500,22 @@ static inline int dma_set_seg_boundary(s
return -EIO;
}

+static inline unsigned int dma_get_min_align_mask(struct device *dev)
+{
+ if (dev->dma_parms)
+ return dev->dma_parms->min_align_mask;
+ return 0;
+}
+
+static inline int dma_set_min_align_mask(struct device *dev,
+ unsigned int min_align_mask)
+{
+ if (WARN_ON_ONCE(!dev->dma_parms))
+ return -EIO;
+ dev->dma_parms->min_align_mask = min_align_mask;
+ return 0;
+}
+
static inline int dma_get_cache_alignment(void)
{
#ifdef ARCH_DMA_MINALIGN