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Message-Id: <20170601093245.29238-31-jack@suse.cz> Date: Thu, 1 Jun 2017 11:32:40 +0200 From: Jan Kara <jack@...e.cz> To: <linux-mm@...ck.org> Cc: Hugh Dickins <hughd@...gle.com>, David Howells <dhowells@...hat.com>, linux-afs@...ts.infradead.org, Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>, linux-nilfs@...r.kernel.org, Bob Peterson <rpeterso@...hat.com>, cluster-devel@...hat.com, Jaegeuk Kim <jaegeuk@...nel.org>, linux-f2fs-devel@...ts.sourceforge.net, tytso@....edu, linux-ext4@...r.kernel.org, Ilya Dryomov <idryomov@...il.com>, "Yan, Zheng" <zyan@...hat.com>, ceph-devel@...r.kernel.org, linux-btrfs@...r.kernel.org, David Sterba <dsterba@...e.com>, "Darrick J . Wong" <darrick.wong@...cle.com>, linux-xfs@...r.kernel.org, Nadia Yvette Chambers <nyc@...omorphy.com>, Jan Kara <jack@...e.cz> Subject: [PATCH 30/35] mm: Implement find_get_entries_range() Implement a variant of find_get_entries() that stops iterating at given index. Some callers want this, so let's provide the interface. Also it makes the interface consistent with find_get_pages(). Signed-off-by: Jan Kara <jack@...e.cz> --- include/linux/pagemap.h | 13 ++++++++++--- include/linux/pagevec.h | 12 ++++++++++-- mm/filemap.c | 32 ++++++++++++++++++++++++-------- mm/swap.c | 11 ++++++----- 4 files changed, 50 insertions(+), 18 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 283d191c18be..df128a56f44b 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -333,9 +333,16 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping, struct page *find_get_entry(struct address_space *mapping, pgoff_t offset); struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset); -unsigned find_get_entries(struct address_space *mapping, pgoff_t *start, - unsigned int nr_entries, struct page **entries, - pgoff_t *indices); +unsigned find_get_entries_range(struct address_space *mapping, pgoff_t *start, + pgoff_t end, unsigned int nr_entries, + struct page **entries, pgoff_t *indices); +static inline unsigned find_get_entries(struct address_space *mapping, + pgoff_t *start, unsigned int nr_entries, + struct page **entries, pgoff_t *indices) +{ + return find_get_entries_range(mapping, start, (pgoff_t)-1, nr_entries, + entries, indices); +} unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start, pgoff_t end, unsigned int nr_pages, struct page **pages); diff --git a/include/linux/pagevec.h b/include/linux/pagevec.h index 3798c142338d..93308689d6a7 100644 --- a/include/linux/pagevec.h +++ b/include/linux/pagevec.h @@ -22,10 +22,18 @@ struct pagevec { void __pagevec_release(struct pagevec *pvec); void __pagevec_lru_add(struct pagevec *pvec); -unsigned pagevec_lookup_entries(struct pagevec *pvec, +unsigned pagevec_lookup_entries_range(struct pagevec *pvec, + struct address_space *mapping, + pgoff_t *start, pgoff_t end, + unsigned nr_entries, pgoff_t *indices); +static inline unsigned pagevec_lookup_entries(struct pagevec *pvec, struct address_space *mapping, pgoff_t *start, unsigned nr_entries, - pgoff_t *indices); + pgoff_t *indices) +{ + return pagevec_lookup_entries_range(pvec, mapping, start, (pgoff_t)-1, + nr_entries, indices); +} void pagevec_remove_exceptionals(struct pagevec *pvec); unsigned pagevec_lookup_range(struct pagevec *pvec, struct address_space *mapping, diff --git a/mm/filemap.c b/mm/filemap.c index de12b7355821..e55100459710 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1354,9 +1354,10 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset, EXPORT_SYMBOL(pagecache_get_page); /** - * find_get_entries - gang pagecache lookup + * find_get_entries_range - gang pagecache lookup * @mapping: The address_space to search * @start: The starting page cache index + * @end: The final page cache index (inclusive) * @nr_entries: The maximum number of entries * @entries: Where the resulting entries are placed * @indices: The cache indices corresponding to the entries in @entries @@ -1376,9 +1377,9 @@ EXPORT_SYMBOL(pagecache_get_page); * find_get_entries() returns the number of pages and shadow entries which were * found. It also updates @start to index the next page for the traversal. */ -unsigned find_get_entries(struct address_space *mapping, - pgoff_t *start, unsigned int nr_entries, - struct page **entries, pgoff_t *indices) +unsigned find_get_entries_range(struct address_space *mapping, + pgoff_t *start, pgoff_t end, unsigned int nr_entries, + struct page **entries, pgoff_t *indices) { void **slot; unsigned int ret = 0; @@ -1390,6 +1391,9 @@ unsigned find_get_entries(struct address_space *mapping, rcu_read_lock(); radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, *start) { struct page *head, *page; + + if (iter.index > end) + break; repeat: page = radix_tree_deref_slot(slot); if (unlikely(!page)) @@ -1425,13 +1429,25 @@ unsigned find_get_entries(struct address_space *mapping, export: indices[ret] = iter.index; entries[ret] = page; - if (++ret == nr_entries) - break; + if (++ret == nr_entries) { + *start = indices[ret - 1] + 1; + goto out; + } } + + /* + * We come here when there is no page beyond @end. We take care to not + * overflow the index @start as it confuses some of the callers. This + * breaks the iteration when there is page at index -1 but that is + * already broken anyway. + */ + if (end == (pgoff_t)-1) + *start = (pgoff_t)-1; + else + *start = end + 1; +out: rcu_read_unlock(); - if (ret) - *start = indices[ret - 1] + 1; return ret; } diff --git a/mm/swap.c b/mm/swap.c index 6ba3dab6e905..88c7eb4e97db 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -889,10 +889,11 @@ void __pagevec_lru_add(struct pagevec *pvec) EXPORT_SYMBOL(__pagevec_lru_add); /** - * pagevec_lookup_entries - gang pagecache lookup + * pagevec_lookup_entries_range - gang pagecache lookup * @pvec: Where the resulting entries are placed * @mapping: The address_space to search * @start: The starting entry index + * @end: The final entry index (inclusive) * @nr_entries: The maximum number of entries * @indices: The cache indices corresponding to the entries in @pvec * @@ -908,13 +909,13 @@ EXPORT_SYMBOL(__pagevec_lru_add); * pagevec_lookup_entries() returns the number of entries which were * found. It also updates @start to index the next page for the traversal. */ -unsigned pagevec_lookup_entries(struct pagevec *pvec, +unsigned pagevec_lookup_entries_range(struct pagevec *pvec, struct address_space *mapping, - pgoff_t *start, unsigned nr_pages, + pgoff_t *start, pgoff_t end, unsigned nr_pages, pgoff_t *indices) { - pvec->nr = find_get_entries(mapping, start, nr_pages, - pvec->pages, indices); + pvec->nr = find_get_entries_range(mapping, start, end, nr_pages, + pvec->pages, indices); return pagevec_count(pvec); } -- 2.12.3
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