[SRU][PATCH 01/13] driver core: add a min_align_mask field to struct device_dma_parameters

Khalid Elmously khalid.elmously at canonical.com
Thu Oct 7 18:06:32 UTC 2021


From: Jianxiong Gao <jxgao at google.com>

BugLink: https://bugs.launchpad.net/bugs/1943902

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 at google.com>
Signed-off-by: Christoph Hellwig <hch at lst.de>
Acked-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com>
(cherry picked from commit 36950f2da1ea4cb683be174f6f581e25b2d33e71)
Signed-off-by: Khalid Elmously <khalid.elmously at canonical.com>
---
 include/linux/device.h      |  1 +
 include/linux/dma-mapping.h | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/linux/device.h b/include/linux/device.h
index 227d58c4da07d..415da4a591e5d 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -993,6 +993,7 @@ struct device_dma_parameters {
 	 * sg limitations.
 	 */
 	unsigned int max_segment_size;
+	unsigned int min_align_mask;
 	unsigned long segment_boundary_mask;
 };
 
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index a4930310d0c7b..6cbf977b3e034 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -748,6 +748,22 @@ static inline int dma_set_seg_boundary(struct device *dev, unsigned long mask)
 	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
-- 
2.17.1




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