From f7470591f8db1a72ce9f7ab49cb13c2b21b92002 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Sat, 5 Oct 2024 21:01:12 +0100 Subject: mm: convert page_to_pgoff() to page_pgoff() Patch series "page->index removals in mm", v2. As part of shrinking struct page, we need to stop using page->index. This patchset gets rid of most of the remaining references to page->index in mm, as well as increasing the number of functions which take a const folio/page pointer. It shrinks the text segment of mm by a few hundred bytes in my test config, probably mostly from removing calls to compound_head() in page_to_pgoff(). This patch (of 7): Change the function signature to pass in the folio as all three callers have it. This removes a reference to page->index, which we're trying to get rid of. And add kernel-doc. Link: https://lkml.kernel.org/r/20241005200121.3231142-1-willy@infradead.org Link: https://lkml.kernel.org/r/20241005200121.3231142-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- include/linux/mm.h | 2 +- include/linux/pagemap.h | 31 +++++++++++++++++-------------- 2 files changed, 18 insertions(+), 15 deletions(-) (limited to 'include') diff --git a/include/linux/mm.h b/include/linux/mm.h index 08e487e5850a..78848fbefe94 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1895,7 +1895,7 @@ static inline unsigned long page_to_section(const struct page *page) * * Return: The Page Frame Number of the first page in the folio. */ -static inline unsigned long folio_pfn(struct folio *folio) +static inline unsigned long folio_pfn(const struct folio *folio) { return page_to_pfn(&folio->page); } diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 68a5f1ff3301..bcf0865a38ae 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -1011,22 +1011,25 @@ static inline struct folio *read_mapping_folio(struct address_space *mapping, return read_cache_folio(mapping, index, NULL, file); } -/* - * Get the offset in PAGE_SIZE (even for hugetlb pages). +/** + * page_pgoff - Calculate the logical page offset of this page. + * @folio: The folio containing this page. + * @page: The page which we need the offset of. + * + * For file pages, this is the offset from the beginning of the file + * in units of PAGE_SIZE. For anonymous pages, this is the offset from + * the beginning of the anon_vma in units of PAGE_SIZE. This will + * return nonsense for KSM pages. + * + * Context: Caller must have a reference on the folio or otherwise + * prevent it from being split or freed. + * + * Return: The offset in units of PAGE_SIZE. */ -static inline pgoff_t page_to_pgoff(struct page *page) +static inline pgoff_t page_pgoff(const struct folio *folio, + const struct page *page) { - struct page *head; - - if (likely(!PageTransTail(page))) - return page->index; - - head = compound_head(page); - /* - * We don't initialize ->index for tail pages: calculate based on - * head page - */ - return head->index + page - head; + return folio->index + folio_page_idx(folio, page); } /* -- cgit v1.2.3