swiotlb: ensure that page-sized mappings are page-aligned

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>

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 975b8fc4f1e1143dcdd295731cf1fc18cf0561fe..a8d74a733a38b54a912f5e292f0a15a2cfff4a95 100644 (file)
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -483,11 +483,11 @@ 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;