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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: akpm@linux-foundation.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
	Jeff Layton <jlayton@kernel.org>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	William Kucharski <william.kucharski@oracle.com>
Subject: [PATCH v11 13/33] mm/filemap: Add folio_index(), folio_file_page() and folio_contains()
Date: Mon, 14 Jun 2021 21:14:15 +0100	[thread overview]
Message-ID: <20210614201435.1379188-14-willy@infradead.org> (raw)
In-Reply-To: <20210614201435.1379188-1-willy@infradead.org>

folio_index() is the equivalent of page_index() for folios.
folio_file_page() is the equivalent of find_subpage().
folio_contains() is the equivalent of thp_contains().

No changes to generated code.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jeff Layton <jlayton@kernel.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
---
 include/linux/pagemap.h | 56 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 91aaf3207ad0..37a4b583abad 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -386,6 +386,62 @@ static inline bool thp_contains(struct page *head, pgoff_t index)
 	return page_index(head) == (index & ~(thp_nr_pages(head) - 1UL));
 }
 
+#define swapcache_index(folio)	__page_file_index(&(folio)->page)
+
+/**
+ * folio_index - File index of a folio.
+ * @folio: The folio.
+ *
+ * For a folio which is either in the page cache or the swap cache,
+ * return its index within the address_space it belongs to.  If you know
+ * the page is definitely in the page cache, you can look at the folio's
+ * index directly.
+ *
+ * Return: The index (offset in units of pages) of a folio in its file.
+ */
+static inline pgoff_t folio_index(struct folio *folio)
+{
+        if (unlikely(folio_swapcache(folio)))
+                return swapcache_index(folio);
+        return folio->index;
+}
+
+/**
+ * folio_file_page - The page for a particular index.
+ * @folio: The folio which contains this index.
+ * @index: The index we want to look up.
+ *
+ * Sometimes after looking up a folio in the page cache, we need to
+ * obtain the specific page for an index (eg a page fault).
+ *
+ * Return: The page containing the file data for this index.
+ */
+static inline struct page *folio_file_page(struct folio *folio, pgoff_t index)
+{
+	/* HugeTLBfs indexes the page cache in units of hpage_size */
+	if (folio_hugetlb(folio))
+		return &folio->page;
+	return folio_page(folio, index & (folio_nr_pages(folio) - 1));
+}
+
+/**
+ * folio_contains - Does this folio contain this index?
+ * @folio: The folio.
+ * @index: The page index within the file.
+ *
+ * Context: The caller should have the page locked in order to prevent
+ * (eg) shmem from moving the page between the page cache and swap cache
+ * and changing its index in the middle of the operation.
+ * Return: true or false.
+ */
+static inline bool folio_contains(struct folio *folio, pgoff_t index)
+{
+	/* HugeTLBfs indexes the page cache in units of hpage_size */
+	if (folio_hugetlb(folio))
+		return folio->index == index;
+	return index - folio_index(folio) < folio_nr_pages(folio);
+}
+
 /*
  * Given the page we found in the page cache, return the page corresponding
  * to this index in the file
-- 
2.30.2


  parent reply	other threads:[~2021-06-14 20:24 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-14 20:14 [PATCH v11 00/33] Memory folios Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 01/33] mm: Convert get_page_unless_zero() to return bool Matthew Wilcox (Oracle)
2021-06-15  6:24   ` Christoph Hellwig
2021-06-14 20:14 ` [PATCH v11 02/33] mm: Introduce struct folio Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 03/33] mm: Add folio_pgdat(), folio_zone() and folio_zonenum() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 04/33] mm/vmstat: Add functions to account folio statistics Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 05/33] mm/debug: Add VM_BUG_ON_FOLIO() and VM_WARN_ON_ONCE_FOLIO() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 06/33] mm: Add folio reference count functions Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 07/33] mm: Add folio_put() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 08/33] mm: Add folio_get() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 09/33] mm: Add folio_try_get_rcu() Matthew Wilcox (Oracle)
2021-06-15  6:25   ` Christoph Hellwig
2021-06-14 20:14 ` [PATCH v11 10/33] mm: Add folio flag manipulation functions Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 11/33] mm/lru: Add folio LRU functions Matthew Wilcox (Oracle)
2021-06-15  6:27   ` Christoph Hellwig
2021-06-14 20:14 ` [PATCH v11 12/33] mm: Handle per-folio private data Matthew Wilcox (Oracle)
2021-06-14 20:14 ` Matthew Wilcox (Oracle) [this message]
2021-06-14 20:14 ` [PATCH v11 14/33] mm/filemap: Add folio_next_index() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 15/33] mm/filemap: Add folio_offset() and folio_file_offset() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 16/33] mm/util: Add folio_mapping() and folio_file_mapping() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 17/33] mm/memcg: Add folio wrappers for various functions Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 18/33] mm/filemap: Add folio_unlock() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 19/33] mm/filemap: Add folio_lock() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 20/33] mm/filemap: Add folio_lock_killable() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 21/33] mm/filemap: Add __folio_lock_async() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 22/33] mm/filemap: Add folio_wait_locked() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 23/33] mm/filemap: Add __folio_lock_or_retry() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 24/33] mm/swap: Add folio_rotate_reclaimable() Matthew Wilcox (Oracle)
2021-06-15  6:29   ` Christoph Hellwig
2021-06-14 20:14 ` [PATCH v11 25/33] mm/filemap: Add folio_end_writeback() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 26/33] mm/writeback: Add folio_wait_writeback() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 27/33] mm/writeback: Add folio_wait_stable() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 28/33] mm/filemap: Add folio_wait_bit() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 29/33] mm/filemap: Add folio_wake_bit() Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 30/33] mm/filemap: Convert page wait queues to be folios Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 31/33] mm/filemap: Add folio private_2 functions Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 32/33] fs/netfs: Add folio fscache functions Matthew Wilcox (Oracle)
2021-06-14 20:14 ` [PATCH v11 33/33] mm: Add folio_mapped() Matthew Wilcox (Oracle)
2021-06-15  6:31   ` Christoph Hellwig
2021-06-16  9:16 ` [PATCH v11 32/33] fs/netfs: Add folio fscache functions David Howells
2021-06-16  9:19 ` [PATCH v11 01/33] mm: Convert get_page_unless_zero() to return bool David Howells
2021-06-16  9:31 ` [PATCH v11 02/33] mm: Introduce struct folio David Howells
2021-06-16  9:36 ` [PATCH v11 04/33] mm/vmstat: Add functions to account folio statistics David Howells
2021-06-16  9:54 ` [PATCH v11 05/33] mm/debug: Add VM_BUG_ON_FOLIO() and VM_WARN_ON_ONCE_FOLIO() David Howells
2021-06-16  9:55 ` [PATCH v11 06/33] mm: Add folio reference count functions David Howells
2021-06-16  9:55 ` [PATCH v11 07/33] mm: Add folio_put() David Howells
2021-06-16  9:56 ` [PATCH v11 08/33] mm: Add folio_get() David Howells
2021-06-16  9:58 ` [PATCH v11 10/33] mm: Add folio flag manipulation functions David Howells
2021-06-16 10:00 ` [PATCH v11 11/33] mm/lru: Add folio LRU functions David Howells
2021-06-16 10:03 ` [PATCH v11 13/33] mm/filemap: Add folio_index(), folio_file_page() and folio_contains() David Howells
2021-06-16 11:38   ` Matthew Wilcox
2021-06-16 10:04 ` [PATCH v11 14/33] mm/filemap: Add folio_next_index() David Howells
2021-06-16 10:05 ` [PATCH v11 15/33] mm/filemap: Add folio_offset() and folio_file_offset() David Howells
2021-06-16 10:10 ` [PATCH v11 16/33] mm/util: Add folio_mapping() and folio_file_mapping() David Howells
2021-06-16 10:13 ` [PATCH v11 18/33] mm/filemap: Add folio_unlock() David Howells
2021-06-16 10:17 ` [PATCH v11 19/33] mm/filemap: Add folio_lock() David Howells
2021-06-16 10:22 ` [PATCH v11 21/33] mm/filemap: Add __folio_lock_async() David Howells
2021-06-16 10:23 ` [PATCH v11 22/33] mm/filemap: Add folio_wait_locked() David Howells
2021-06-16 10:27 ` [PATCH v11 24/33] mm/swap: Add folio_rotate_reclaimable() David Howells
2021-06-16 11:46   ` Matthew Wilcox
2021-06-16 10:30 ` [PATCH v11 26/33] mm/writeback: Add folio_wait_writeback() David Howells
2021-06-16 11:55   ` Matthew Wilcox
2021-06-16 10:32 ` [PATCH v11 27/33] mm/writeback: Add folio_wait_stable() David Howells
2021-06-16 10:33 ` [PATCH v11 28/33] mm/filemap: Add folio_wait_bit() David Howells
2021-06-16 10:35 ` [PATCH v11 30/33] mm/filemap: Convert page wait queues to be folios David Howells
2021-06-16 10:37 ` [PATCH v11 33/33] mm: Add folio_mapped() David Howells
2021-06-16 10:41 ` [PATCH v11 02/33] mm: Introduce struct folio David Howells
2021-06-16 10:54 ` [PATCH v11 00/33] Memory folios David Howells

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