mm: add find_lock_head (a8cf7f27) · Commits · 戴 / test

include/linux/pagemap.h

+26 −6

Original line number	Diff line number	Diff line
		@@ -279,6 +279,7 @@ pgoff_t page_cache_prev_miss(struct address_space *mapping,
		#define FGP_NOFS 0x00000010
		#define FGP_NOWAIT 0x00000020
		#define FGP_FOR_MMAP 0x00000040
		#define FGP_HEAD 0x00000080

		struct page pagecache_get_page(struct address_space mapping, pgoff_t offset,
		int fgp_flags, gfp_t cache_gfp_mask);
		@@ -310,18 +311,37 @@ static inline struct page find_get_page_flags(struct address_space mapping,
		* @mapping: the address_space to search
		* @offset: the page index
		*
		* Looks up the page cache slot at @mapping & @offset. If there is a
		* Looks up the page cache entry at @mapping & @offset. If there is a
		* page cache page, it is returned locked and with an increased
		* refcount.
		*
		* Otherwise, %NULL is returned.
		*
		* find_lock_page() may sleep.
		* Context: May sleep.
		* Return: A struct page or %NULL if there is no page in the cache for this
		* index.
		*/
		static inline struct page find_lock_page(struct address_space mapping,
		pgoff_t offset)
		pgoff_t index)
		{
		return pagecache_get_page(mapping, index, FGP_LOCK, 0);
		}

		/**
		* find_lock_head - Locate, pin and lock a pagecache page.
		* @mapping: The address_space to search.
		* @offset: The page index.
		*
		* Looks up the page cache entry at @mapping & @offset. If there is a
		* page cache page, its head page is returned locked and with an increased
		* refcount.
		*
		* Context: May sleep.
		* Return: A struct page which is !PageTail, or %NULL if there is no page
		* in the cache for this index.
		*/
		static inline struct page find_lock_head(struct address_space mapping,
		pgoff_t index)
		{
		return pagecache_get_page(mapping, offset, FGP_LOCK, 0);
		return pagecache_get_page(mapping, index, FGP_LOCK \| FGP_HEAD, 0);
		}

		/**

mm/filemap.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -1737,6 +1737,8 @@ repeat:
		*
		* * %FGP_ACCESSED - The page will be marked accessed.
		* * %FGP_LOCK - The page is returned locked.
		* * %FGP_HEAD - If the page is present and a THP, return the head page
		* rather than the exact page specified by the index.
		* * %FGP_CREAT - If no page is present then a new page is allocated using
		* @gfp_mask and added to the page cache and the VM's LRU list.
		* The page is returned locked and with an increased refcount.
		@@ -1765,7 +1767,6 @@ repeat:
		page = NULL;
		if (!page)
		goto no_page;
		page = find_subpage(page, index);

		if (fgp_flags & FGP_LOCK) {
		if (fgp_flags & FGP_NOWAIT) {
		@@ -1778,12 +1779,12 @@ repeat:
		}

		/* Has the page been truncated? */
		if (unlikely(compound_head(page)->mapping != mapping)) {
		if (unlikely(page->mapping != mapping)) {
		unlock_page(page);
		put_page(page);
		goto repeat;
		}
		VM_BUG_ON_PAGE(page->index != index, page);
		VM_BUG_ON_PAGE(!thp_contains(page, index), page);
		}

		if (fgp_flags & FGP_ACCESSED)
		@@ -1793,6 +1794,8 @@ repeat:
		if (page_is_idle(page))
		clear_page_idle(page);
		}
		if (!(fgp_flags & FGP_HEAD))
		page = find_subpage(page, index);

		no_page:
		if (!page && (fgp_flags & FGP_CREAT)) {

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