The patch titled
Subject: mm: re-allow pinning of zero pfns
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-re-allow-pinning-of-zero-pfns.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-re-allow-pinning-of-zero-pfns.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Alex Williamson <alex.williamson@xxxxxxxxxx>
Subject: mm: re-allow pinning of zero pfns
Date: Fri, 10 Jun 2022 16:35:13 -0600
The commit referenced below subtly and inadvertently changed the logic to
disallow pinning of zero pfns. This breaks device assignment with vfio
and potentially various other users of gup. Exclude the zero page test
from the negation.
Link: https://lkml.kernel.org/r/165490039431.944052.12458624139225785964.stgit@omen
Fixes: 1c563432588d ("mm: fix is_pinnable_page against a cma page")
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: John Dias <joaodias@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Zhangfei Gao <zhangfei.gao@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/mm.h~mm-re-allow-pinning-of-zero-pfns
+++ a/include/linux/mm.h
@@ -1600,7 +1600,7 @@ static inline bool is_pinnable_page(stru
if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE)
return false;
#endif
- return !(is_zone_movable_page(page) || is_zero_pfn(page_to_pfn(page)));
+ return !is_zone_movable_page(page) || is_zero_pfn(page_to_pfn(page));
}
#else
static inline bool is_pinnable_page(struct page *page)
_
Patches currently in -mm which might be from alex.williamson@xxxxxxxxxx are
mm-re-allow-pinning-of-zero-pfns.patch
