From 6cdef2ddce2b7de8faca69061a6780080cfecc10 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Sat, 8 Feb 2025 15:52:56 +0000 Subject: fb_defio: do not use deprecated page->mapping, index fields MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With the introduction of mapping_wrprotect_range() there is no need to use folio_mkclean() in order to write-protect mappings of frame buffer pages, and therefore no need to inappropriately set kernel-allocated page->index, mapping fields to permit this operation. Instead, store the pointer to the page cache object for the mapped driver in the fb_deferred_io object, and use the already stored page offset from the pageref object to look up mappings in order to write-protect them. This is justified, as for the page objects to store a mapping pointer at the point of assignment of pages, they must all reference the same underlying address_space object. Since the life time of the pagerefs is also the lifetime of the fb_deferred_io object, storing the pointer here makes sense. This eliminates the need for all of the logic around setting and maintaining page->index,mapping which we remove. This eliminates the use of folio_mkclean() entirely but otherwise should have no functional change. [lorenzo.stoakes@oracle.com: fixup unused variable warnings] Link: https://lkml.kernel.org/r/d4018405-2762-4385-a816-e54cc23839ac@lucifer.local Link: https://lkml.kernel.org/r/81171ab16c14e3df28f6de9d14982cee528d8519.1739029358.git.lorenzo.stoakes@oracle.com Signed-off-by: Lorenzo Stoakes Tested-by: Kajtar Zsolt Acked-by: Thomas Zimmermann Cc: David Hildenbrand Cc: Helge Deller Cc: Jaya Kumar Cc: Maíra Canal Cc: Matthew Wilcox Cc: Simona Vetter Signed-off-by: Andrew Morton --- include/linux/fb.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/fb.h b/include/linux/fb.h index 5ba187e08cf7..cd653862ab99 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -225,6 +225,7 @@ struct fb_deferred_io { int open_count; /* number of opened files; protected by fb_info lock */ struct mutex lock; /* mutex that protects the pageref list */ struct list_head pagereflist; /* list of pagerefs for touched pages */ + struct address_space *mapping; /* page cache object for fb device */ /* callback */ struct page *(*get_page)(struct fb_info *info, unsigned long offset); void (*deferred_io)(struct fb_info *info, struct list_head *pagelist); -- cgit v1.2.3