[PATCH 4.4 076/101] swiotlb: ensure that page-sized mappings are page-aligned

Greg Kroah-Hartman
2017-07-03T14:58:31Z

From: Nikita Yushchenko <nikita.yoush@cogentembedded.com>

[ Upstream commit 602d9858f07c72eab64f5f00e2fae55f9902cfbe ]

Some drivers 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.

Without this fix, nvme hits BUG() in nvme_setup_prps(), because that routine
assumes page-aligned mappings.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Konrad Rzeszutek Wilk <konrad@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
lib/swiotlb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -452,11 +452,11 @@ phys_addr_t swiotlb_tbl_map_single(struc
: 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;