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authorAlex Williamson <alex.williamson@redhat.com>2022-08-10 10:53:59 -0600
committerAndrew Morton <akpm@linux-foundation.org>2022-08-28 14:02:44 -0700
commitfcab34b433e2c13e333b2f53c4a8409eadc432c7 (patch)
treef41557fa60c6d91fbd04fa4a057e1498476264e9 /include/linux/mm.h
parentvmcoreinfo: add kallsyms_num_syms symbol (diff)
downloadlinux-dev-fcab34b433e2c13e333b2f53c4a8409eadc432c7.tar.xz
linux-dev-fcab34b433e2c13e333b2f53c4a8409eadc432c7.zip
mm: re-allow pinning of zero pfns (again)
The below referenced commit makes the same error as 1c563432588d ("mm: fix is_pinnable_page against a cma page"), re-interpreting the logic to exclude pinning of the zero page, which breaks device assignment with vfio. To avoid further subtle mistakes, split the logic into discrete tests. [akpm@linux-foundation.org: simplify comment, per John] Link: https://lkml.kernel.org/r/166015037385.760108.16881097713975517242.stgit@omen Link: https://lore.kernel.org/all/165490039431.944052.12458624139225785964.stgit@omen Fixes: f25cbb7a95a2 ("mm: add zone device coherent type memory support") Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Suggested-by: Matthew Wilcox <willy@infradead.org> Suggested-by: Felix Kuehling <felix.kuehling@amd.com> Tested-by: Slawomir Laba <slawomirx.laba@intel.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Cc: Alex Sierra <alex.sierra@amd.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Alistair Popple <apopple@nvidia.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to '')
-rw-r--r--include/linux/mm.h13
1 files changed, 10 insertions, 3 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 982f2607180b..21f8b27bd9fd 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1544,9 +1544,16 @@ static inline bool is_longterm_pinnable_page(struct page *page)
if (mt == MIGRATE_CMA || mt == MIGRATE_ISOLATE)
return false;
#endif
- return !(is_device_coherent_page(page) ||
- is_zone_movable_page(page) ||
- is_zero_pfn(page_to_pfn(page)));
+ /* The zero page may always be pinned */
+ if (is_zero_pfn(page_to_pfn(page)))
+ return true;
+
+ /* Coherent device memory must always allow eviction. */
+ if (is_device_coherent_page(page))
+ return false;
+
+ /* Otherwise, non-movable zone pages can be pinned. */
+ return !is_zone_movable_page(page);
}
#else
static inline bool is_longterm_pinnable_page(struct page *page)