[PATCH 4/4] mm: Update DMA zones description

Nicolas Saenz Julienne
2020-10-01T16:18:06Z

The default behavior for arm64 changed, so reflect that.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
include/linux/mmzone.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index fb3bf696c05e..d28ce77ccc2a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -363,8 +363,9 @@ enum zone_type {
* - arm only uses ZONE_DMA, the size, up to 4G, may vary depending on
* the specific device.
*
- * - arm64 has a fixed 1G ZONE_DMA and ZONE_DMA32 for the rest of the
- * lower 4G.
+ * - arm64 uses a single 4GB ZONE_DMA, except on the Raspberry Pi 4,
+ * in which ZONE_DMA covers the first GB and ZONE_DMA32 the rest of
+ * the lower 4GB.
*
* - powerpc only uses ZONE_DMA, the size, up to 2G, may vary
* depending on the specific device.
--
2.28.0