[PATCH v3 17/25] gup: Don't allow FOLL_LONGTERM pinning of FS DAX pages

Alistair Popple
2024-11-22T01:43:48Z

Longterm pinning of FS DAX pages should already be disallowed by
various pXX_devmap checks. However a future change will cause these
checks to be invalid for FS DAX pages so make
folio_is_longterm_pinnable() return false for FS DAX pages.

Signed-off-by: Alistair Popple <apopple@nvidia.com>
---
include/linux/mm.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 22c651b..4f9ae37 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2004,6 +2004,10 @@ static inline bool folio_is_longterm_pinnable(struct folio *folio)
if (folio_is_device_coherent(folio))
return false;

+ /* DAX must also always allow eviction. */
+ if (folio_is_fsdax(folio))
+ return false;
+
/* Otherwise, non-movable zone folios can be pinned. */
return !folio_is_zone_movable(folio);

--
git-series 0.9.1