+ mm-gup-dont-allow-foll_longterm-pinning-of-fs-dax-pages.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/gup: don't allow FOLL_LONGTERM pinning of FS DAX pages
has been added to the -mm mm-unstable branch.  Its filename is
     mm-gup-dont-allow-foll_longterm-pinning-of-fs-dax-pages.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-gup-dont-allow-foll_longterm-pinning-of-fs-dax-pages.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Alistair Popple <apopple@nvidia.com>
Subject: mm/gup: don't allow FOLL_LONGTERM pinning of FS DAX pages
Date: Tue, 7 Jan 2025 14:42:34 +1100

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.

Link: https://lkml.kernel.org/r/8bd0a8c0f62e2d2d8ece6f445580d20b73e3decd.1736221254.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/mm.h |    4 ++++
 1 file changed, 4 insertions(+)

--- a/include/linux/mm.h~mm-gup-dont-allow-foll_longterm-pinning-of-fs-dax-pages
+++ a/include/linux/mm.h
@@ -2099,6 +2099,10 @@ static inline bool folio_is_longterm_pin
 	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);
 
_

Patches currently in -mm which might be from apopple@nvidia.com are

fuse-fix-dax-truncate-punch_hole-fault-path.patch
fs-dax-return-unmapped-busy-pages-from-dax_layout_busy_page_range.patch
fs-dax-dont-skip-locked-entries-when-scanning-entries.patch
fs-dax-refactor-wait-for-dax-idle-page.patch
fs-dax-create-a-common-implementation-to-break-dax-layouts.patch
fs-dax-always-remove-dax-page-cache-entries-when-breaking-layouts.patch
fs-dax-ensure-all-pages-are-idle-prior-to-filesystem-unmount.patch
fs-dax-remove-page_mapping_dax_shared-mapping-flag.patch
mm-gup-remove-redundant-check-for-pci-p2pdma-page.patch
mm-mm_init-move-p2pdma-page-refcount-initialisation-to-p2pdma.patch
mm-allow-compound-zone-device-pages.patch
mm-memory-enhance-insert_page_into_pte_locked-to-create-writable-mappings.patch
mm-memory-add-vmf_insert_page_mkwrite.patch
rmap-add-support-for-pud-sized-mappings-to-rmap.patch
huge_memory-add-vmf_insert_folio_pud.patch
huge_memory-add-vmf_insert_folio_pmd.patch
memremap-add-is_devdax_page-and-is_fsdax_page-helpers.patch
mm-gup-dont-allow-foll_longterm-pinning-of-fs-dax-pages.patch
proc-task_mmu-mark-devdax-and-fsdax-pages-as-always-unpinned.patch
mm-mlock-skip-zone_device-pmds-during-mlock.patch
fs-dax-properly-refcount-fs-dax-pages.patch
device-dax-properly-refcount-device-dax-pages-when-mapping.patch
mm-remove-pxx_devmap-callers.patch
mm-remove-devmap-related-functions-and-page-table-bits.patch
revert-riscv-mm-add-support-for-zone_device.patch