From: Jianxiong Gao <jxgao@google.com>
Date: Mon, 1 Feb 2021 10:30:15 -0800
Subject: driver core: add a min_align_mask field to struct
 device_dma_parameters
Git-commit: 36950f2da1ea4cb683be174f6f581e25b2d33e71
Patch-mainline: v5.12-rc1
References: bsc#1191851

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>
Acked-by: Joerg Roedel <jroedel@suse.de>
---
 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
@@ -876,6 +876,7 @@ 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
@@ -756,6 +756,22 @@ 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