6.9-stable review patch. If anyone has any objections, please let me know.
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From: Xu Yang xu.yang_2@nxp.com
commit 79c137454815ba5554caa8eeb4ad5c94e96e45ce upstream.
Add mapping_max_folio_size() to get the maximum folio size for this pagecache mapping.
Fixes: 5d8edfb900d5 ("iomap: Copy larger chunks from userspace") Cc: stable@vger.kernel.org Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Xu Yang xu.yang_2@nxp.com Link: https://lore.kernel.org/r/20240521114939.2541461-1-xu.yang_2@nxp.com Reviewed-by: Ritesh Harjani (IBM) ritesh.list@gmail.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Matthew Wilcox (Oracle) willy@infradead.org Signed-off-by: Christian Brauner brauner@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/linux/pagemap.h | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-)
--- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -344,6 +344,19 @@ static inline void mapping_set_gfp_mask( m->gfp_mask = mask; }
+/* + * There are some parts of the kernel which assume that PMD entries + * are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then, + * limit the maximum allocation order to PMD size. I'm not aware of any + * assumptions about maximum order if THP are disabled, but 8 seems like + * a good order (that's 1MB if you're using 4kB pages) + */ +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER +#else +#define MAX_PAGECACHE_ORDER 8 +#endif + /** * mapping_set_large_folios() - Indicate the file supports large folios. * @mapping: The file. @@ -370,6 +383,14 @@ static inline bool mapping_large_folio_s test_bit(AS_LARGE_FOLIO_SUPPORT, &mapping->flags); }
+/* Return the maximum folio size for this pagecache mapping, in bytes. */ +static inline size_t mapping_max_folio_size(struct address_space *mapping) +{ + if (mapping_large_folio_support(mapping)) + return PAGE_SIZE << MAX_PAGECACHE_ORDER; + return PAGE_SIZE; +} + static inline int filemap_nr_thps(struct address_space *mapping) { #ifdef CONFIG_READ_ONLY_THP_FOR_FS @@ -528,19 +549,6 @@ static inline void *detach_page_private( return folio_detach_private(page_folio(page)); }
-/* - * There are some parts of the kernel which assume that PMD entries - * are exactly HPAGE_PMD_ORDER. Those should be fixed, but until then, - * limit the maximum allocation order to PMD size. I'm not aware of any - * assumptions about maximum order if THP are disabled, but 8 seems like - * a good order (that's 1MB if you're using 4kB pages) - */ -#ifdef CONFIG_TRANSPARENT_HUGEPAGE -#define MAX_PAGECACHE_ORDER HPAGE_PMD_ORDER -#else -#define MAX_PAGECACHE_ORDER 8 -#endif - #ifdef CONFIG_NUMA struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order); #else