[PATCH] swiotlb: ensure that page-sized mappings are page-aligned

From: Nikita Yushchenko
Date: Tue Jan 03 2017 - 06:31:14 EST


Some drivers (e.g. nvme) do depend on page mappings to be page
aligned.

Swiotlb already enforces such alignment for mappings greater than page,
extend that to page-sized mappings as well.

Signed-off-by: Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>
---
lib/swiotlb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index cb1b54e..b0ee957 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -453,11 +453,11 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
: 1UL << (BITS_PER_LONG - IO_TLB_SHIFT);

/*
- * For mappings greater than a page, we limit the stride (and
- * hence alignment) to a page size.
+ * For mappings greater than or equal to a page, we limit the stride
+ * (and hence alignment) to a page size.
*/
nslots = ALIGN(size, 1 << IO_TLB_SHIFT) >> IO_TLB_SHIFT;
- if (size > PAGE_SIZE)
+ if (size >= PAGE_SIZE)
stride = (1 << (PAGE_SHIFT - IO_TLB_SHIFT));
else
stride = 1;
--
2.1.4