Messages in this thread Patch in this message | | | Subject | [PATCH v3 3/6] folio: Add a function to change the private data attached to a folio | From | David Howells <> | Date | Tue, 02 Nov 2021 08:30:07 +0000 |
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Add a function, folio_change_private(), that will change the private data attached to a folio, without the need to twiddle the private bit or the refcount. It assumes that folio_add_private() has already been called on the page.
Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Link: https://lore.kernel.org/r/162981149911.1901565.17776700811659843340.stgit@warthog.procyon.org.uk/ Link: https://lore.kernel.org/r/163005743485.2472992.5100702469503007023.stgit@warthog.procyon.org.uk/ # v2 ---
include/linux/pagemap.h | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 013cdc90f5fd..569302e4defe 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -229,6 +229,25 @@ static inline void folio_attach_private(struct folio *folio, void *data) folio_set_private(folio); } +/** + * folio_change_private - Change private data on a folio. + * @folio: Folio to change the data on. + * @data: Data to set on the folio. + * + * Change the private data attached to a folio and return the old + * data. The page must previously have had data attached and the data + * must be detached before the folio will be freed. + * + * Return: Data that was previously attached to the folio. + */ +static inline void *folio_change_private(struct folio *folio, void *data) +{ + void *old = folio_get_private(folio); + + folio->private = data; + return old; +} + /** * folio_detach_private - Detach private data from a folio. * @folio: Folio to detach data from.
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