From: Ben Hutchings <ben@decadent.org.uk>
Date: Mon, 24 Feb 2025 01:02:26 +0000 (+0100)
Subject: Revert "xen/swiotlb: add alignment check for dma buffers"
X-Git-Tag: archive/raspbian/5.10.237-1+rpi1^2~27
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=68de87a3aae2f5df4bf3b1fa87991a26e8135de0;p=linux.git

Revert "xen/swiotlb: add alignment check for dma buffers"

Bug-Debian: https://bugs.debian.org/1087807
Bug-Debian: https://bugs.debian.org/1088159
Bug-Debian: https://bugs.debian.org/1093371

This reverts commit a0a8b7bebe1b1f9017b09e1e045f16725e871f9c, which
was commit 9f40ec84a7976d95c34e7cc070939deb103652b0 upstream.  This
caused regressions for a number of drivers under Xen.

Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name revert-xen-swiotlb-add-alignment-check-for-dma-buffe.patch
---

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index 000d02ea4f7..ad3ee4857e1 100644
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -91,15 +91,9 @@ static inline int range_straddles_page_boundary(phys_addr_t p, size_t size)
 {
 	unsigned long next_bfn, xen_pfn = XEN_PFN_DOWN(p);
 	unsigned int i, nr_pages = XEN_PFN_UP(xen_offset_in_page(p) + size);
-	phys_addr_t algn = 1ULL << (get_order(size) + PAGE_SHIFT);
 
 	next_bfn = pfn_to_bfn(xen_pfn);
 
-	/* If buffer is physically aligned, ensure DMA alignment. */
-	if (IS_ALIGNED(p, algn) &&
-	    !IS_ALIGNED((phys_addr_t)next_bfn << XEN_PAGE_SHIFT, algn))
-		return 1;
-
 	for (i = 1; i < nr_pages; i++)
 		if (pfn_to_bfn(++xen_pfn) != ++next_bfn)
 			return 1;