[PATCH 08/12] gup: Don't allow FOLL_LONGTERM pinning of FS DAX pages
From: Alistair Popple <apopple@nvidia.com>
Date: 2024-09-10 04:15:38
Also in:
linux-arm-kernel, linux-cxl, linux-doc, linux-ext4, linux-fsdevel, linux-mm, linux-xfs, lkml, nvdimm
Subsystem:
memory hot(un)plug, memory management - core, the rest · Maintainers:
David Hildenbrand, Oscar Salvador, Andrew Morton, Linus Torvalds
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/memremap.h | 11 +++++++++++ include/linux/mm.h | 4 ++++ 2 files changed, 15 insertions(+)
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 14273e6..6a1406a 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h@@ -187,6 +187,17 @@ static inline bool folio_is_device_coherent(const struct folio *folio) return is_device_coherent_page(&folio->page); } +static inline bool is_device_dax_page(const struct page *page) +{ + return is_zone_device_page(page) && + page_dev_pagemap(page)->type == MEMORY_DEVICE_FS_DAX; +} + +static inline bool folio_is_device_dax(const struct folio *folio) +{ + return is_device_dax_page(&folio->page); +} + #ifdef CONFIG_ZONE_DEVICE void zone_device_page_init(struct page *page); void *memremap_pages(struct dev_pagemap *pgmap, int nid);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ae6d713..935e493 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -1989,6 +1989,10 @@ 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_device_dax(folio)) + return false; + /* Otherwise, non-movable zone folios can be pinned. */ return !folio_is_zone_movable(folio);
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git-series 0.9.1