mm/gup: don't allow FOLL_LONGTERM pinning of FS DAX pages

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/250a31876704b79f7c65b159f3c835e547f052df.1740713401.git-series.apopple@nvidia.com
Signed-off-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Alison Schofield <alison.schofield@intel.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Asahi Lina <lina@asahilina.net>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linmiaohe <linmiaohe@huawei.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Michael "Camp Drill Sergeant" Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 0256a4218dc341967b71575ef4635192edfef99f..4aa151914eabbce589e8f62184d1b72631731525 100644 (file)
--- 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_fsdax_page(const struct page *page)
+{
+       return is_zone_device_page(page) &&
+               page_pgmap(page)->type == MEMORY_DEVICE_FS_DAX;
+}
+
+static inline bool folio_is_fsdax(const struct folio *folio)
+{
+       return is_fsdax_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 c6fb9300f6c052954fa801b8ab1dab186309093a..009484a070744a8a2b19dc9612206579cc263088 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2115,6 +2115,13 @@ static inline bool folio_is_longterm_pinnable(struct folio *folio)
        if (folio_is_device_coherent(folio))
                return false;
 
+       /*
+        * Filesystems can only tolerate transient delays to truncate and
+        * hole-punch operations
+        */
+       if (folio_is_fsdax(folio))
+               return false;
+
        /* Otherwise, non-movable zone folios can be pinned. */
        return !folio_is_zone_movable(folio);