From 14ef1fc72a3e86cea6498193c5e04b4619cb8622 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 5 Mar 2019 15:44:08 -0800 Subject: mm/filemap.c: remove redundant test from find_get_pages_contig After we establish a reference on the page, we check the pointer continues to be in the correct position in i_pages. Checking page->index afterwards is unnecessary; if it were to change, then the pointer to it from the page cache would also move. The check used to be done before grabbing a reference on the page which was racy (see commit 9cbb4cb21b19f ("mm: find_get_pages_contig fixlet")), but nobody noticed that moving the check after grabbing the reference was redundant. Link: http://lkml.kernel.org/r/20190107200224.13260-1-willy@infradead.org Signed-off-by: Matthew Wilcox Reviewed-by: Andrew Morton Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'mm/filemap.c') diff --git a/mm/filemap.c b/mm/filemap.c index 9f5e323e883e..935fbc29aeb1 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1837,16 +1837,6 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, if (unlikely(page != xas_reload(&xas))) goto put_page; - /* - * must check mapping and index after taking the ref. - * otherwise we can get both false positives and false - * negatives, which is just confusing to the caller. - */ - if (!page->mapping || page_to_pgoff(page) != xas.xa_index) { - put_page(page); - break; - } - pages[ret] = page; if (++ret == nr_pages) break; -- cgit v1.2.2 From 35f12f0f5c3bbd60caba89351f45c8eef8ffd423 Mon Sep 17 00:00:00 2001 From: zhengbin Date: Tue, 5 Mar 2019 15:44:21 -0800 Subject: mm/filemap: pass inclusive 'end_byte' parameter to filemap_range_has_page The 'end_byte' parameter of filemap_range_has_page is required to be inclusive, so follow the rule. Link: http://lkml.kernel.org/r/1548678679-18122-1-git-send-email-zhengbin13@huawei.com Fixes: 6be96d3ad34a ("fs: return if direct I/O will trigger writeback") Signed-off-by: zhengbin Reviewed-by: Andrew Morton Reviewed-by: Matthew Wilcox Acked-by: Christoph Hellwig Cc: "Darrick J. Wong" Cc: Amir Goldstein Cc: Dave Chinner Cc: Johannes Weiner Cc: Hugh Dickins Cc: Hou Tao Cc: zhangyi (F) Cc: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/filemap.c') diff --git a/mm/filemap.c b/mm/filemap.c index 935fbc29aeb1..e59fdecdab74 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -3071,7 +3071,7 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from) if (iocb->ki_flags & IOCB_NOWAIT) { /* If there are pages to writeback, return */ if (filemap_range_has_page(inode->i_mapping, pos, - pos + write_len)) + pos + write_len - 1)) return -EAGAIN; } else { written = filemap_write_and_wait_range(mapping, pos, -- cgit v1.2.2 From a862f68a8b360086f248cbc3606029441b5f5197 Mon Sep 17 00:00:00 2001 From: Mike Rapoport Date: Tue, 5 Mar 2019 15:48:42 -0800 Subject: docs/core-api/mm: fix return value descriptions in mm/ Many kernel-doc comments in mm/ have the return value descriptions either misformatted or omitted at all which makes kernel-doc script unhappy: $ make V=1 htmldocs ... ./mm/util.c:36: info: Scanning doc for kstrdup ./mm/util.c:41: warning: No description found for return value of 'kstrdup' ./mm/util.c:57: info: Scanning doc for kstrdup_const ./mm/util.c:66: warning: No description found for return value of 'kstrdup_const' ./mm/util.c:75: info: Scanning doc for kstrndup ./mm/util.c:83: warning: No description found for return value of 'kstrndup' ... Fixing the formatting and adding the missing return value descriptions eliminates ~100 such warnings. Link: http://lkml.kernel.org/r/1549549644-4903-4-git-send-email-rppt@linux.ibm.com Signed-off-by: Mike Rapoport Reviewed-by: Andrew Morton Cc: Jonathan Corbet Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 62 insertions(+), 11 deletions(-) (limited to 'mm/filemap.c') diff --git a/mm/filemap.c b/mm/filemap.c index e59fdecdab74..ae0022f6106d 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -392,6 +392,8 @@ static int filemap_check_and_keep_errors(struct address_space *mapping) * opposed to a regular memory cleansing writeback. The difference between * these two operations is that if a dirty page/buffer is encountered, it must * be waited upon, and not just skipped over. + * + * Return: %0 on success, negative error code otherwise. */ int __filemap_fdatawrite_range(struct address_space *mapping, loff_t start, loff_t end, int sync_mode) @@ -438,6 +440,8 @@ EXPORT_SYMBOL(filemap_fdatawrite_range); * * This is a mostly non-blocking flush. Not suitable for data-integrity * purposes - I/O may not be started against all dirty pages. + * + * Return: %0 on success, negative error code otherwise. */ int filemap_flush(struct address_space *mapping) { @@ -453,6 +457,9 @@ EXPORT_SYMBOL(filemap_flush); * * Find at least one page in the range supplied, usually used to check if * direct writing in this range will trigger a writeback. + * + * Return: %true if at least one page exists in the specified range, + * %false otherwise. */ bool filemap_range_has_page(struct address_space *mapping, loff_t start_byte, loff_t end_byte) @@ -529,6 +536,8 @@ static void __filemap_fdatawait_range(struct address_space *mapping, * Since the error status of the address space is cleared by this function, * callers are responsible for checking the return value and handling and/or * reporting the error. + * + * Return: error status of the address space. */ int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte, loff_t end_byte) @@ -551,6 +560,8 @@ EXPORT_SYMBOL(filemap_fdatawait_range); * Since the error status of the file is advanced by this function, * callers are responsible for checking the return value and handling and/or * reporting the error. + * + * Return: error status of the address space vs. the file->f_wb_err cursor. */ int file_fdatawait_range(struct file *file, loff_t start_byte, loff_t end_byte) { @@ -572,6 +583,8 @@ EXPORT_SYMBOL(file_fdatawait_range); * Use this function if callers don't handle errors themselves. Expected * call sites are system-wide / filesystem-wide data flushers: e.g. sync(2), * fsfreeze(8) + * + * Return: error status of the address space. */ int filemap_fdatawait_keep_errors(struct address_space *mapping) { @@ -623,6 +636,8 @@ EXPORT_SYMBOL(filemap_write_and_wait); * * Note that @lend is inclusive (describes the last byte to be written) so * that this function can be used to write to the very end-of-file (end = -1). + * + * Return: error status of the address space. */ int filemap_write_and_wait_range(struct address_space *mapping, loff_t lstart, loff_t lend) @@ -678,6 +693,8 @@ EXPORT_SYMBOL(__filemap_set_wb_err); * While we handle mapping->wb_err with atomic operations, the f_wb_err * value is protected by the f_lock since we must ensure that it reflects * the latest value swapped in for this file descriptor. + * + * Return: %0 on success, negative error code otherwise. */ int file_check_and_advance_wb_err(struct file *file) { @@ -720,6 +737,8 @@ EXPORT_SYMBOL(file_check_and_advance_wb_err); * * After writing out and waiting on the data, we check and advance the * f_wb_err cursor to the latest value, and return any errors detected there. + * + * Return: %0 on success, negative error code otherwise. */ int file_write_and_wait_range(struct file *file, loff_t lstart, loff_t lend) { @@ -753,6 +772,8 @@ EXPORT_SYMBOL(file_write_and_wait_range); * caller must do that. * * The remove + add is atomic. This function cannot fail. + * + * Return: %0 */ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask) { @@ -867,6 +888,8 @@ error: * * This function is used to add a page to the pagecache. It must be locked. * This function does not add the page to the LRU. The caller must do that. + * + * Return: %0 on success, negative error code otherwise. */ int add_to_page_cache_locked(struct page *page, struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) @@ -1463,7 +1486,7 @@ EXPORT_SYMBOL(page_cache_prev_miss); * If the slot holds a shadow entry of a previously evicted page, or a * swap entry from shmem/tmpfs, it is returned. * - * Otherwise, %NULL is returned. + * Return: the found page or shadow entry, %NULL if nothing is found. */ struct page *find_get_entry(struct address_space *mapping, pgoff_t offset) { @@ -1521,9 +1544,9 @@ EXPORT_SYMBOL(find_get_entry); * If the slot holds a shadow entry of a previously evicted page, or a * swap entry from shmem/tmpfs, it is returned. * - * Otherwise, %NULL is returned. - * * find_lock_entry() may sleep. + * + * Return: the found page or shadow entry, %NULL if nothing is found. */ struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset) { @@ -1563,12 +1586,14 @@ EXPORT_SYMBOL(find_lock_entry); * - FGP_CREAT: If page is not 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. Otherwise, NULL is returned. + * refcount. * * If FGP_LOCK or FGP_CREAT are specified then the function may sleep even * if the GFP flags specified for FGP_CREAT are atomic. * * If there is a page cache page, it is returned with an increased refcount. + * + * Return: the found page or %NULL otherwise. */ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset, int fgp_flags, gfp_t gfp_mask) @@ -1656,8 +1681,7 @@ EXPORT_SYMBOL(pagecache_get_page); * Any shadow entries of evicted pages, or swap entries from * shmem/tmpfs, are included in the returned array. * - * find_get_entries() returns the number of pages and shadow entries - * which were found. + * Return: the number of pages and shadow entries which were found. */ unsigned find_get_entries(struct address_space *mapping, pgoff_t start, unsigned int nr_entries, @@ -1727,8 +1751,8 @@ retry: * indexes. There may be holes in the indices due to not-present pages. * We also update @start to index the next page for the traversal. * - * find_get_pages_range() returns the number of pages which were found. If this - * number is smaller than @nr_pages, the end of specified range has been + * Return: the number of pages which were found. If this number is + * smaller than @nr_pages, the end of specified range has been * reached. */ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start, @@ -1801,7 +1825,7 @@ out: * find_get_pages_contig() works exactly like find_get_pages(), except * that the returned number of pages are guaranteed to be contiguous. * - * find_get_pages_contig() returns the number of pages which were found. + * Return: the number of pages which were found. */ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, unsigned int nr_pages, struct page **pages) @@ -1862,6 +1886,8 @@ EXPORT_SYMBOL(find_get_pages_contig); * * Like find_get_pages, except we only return pages which are tagged with * @tag. We update @index to index the next page for the traversal. + * + * Return: the number of pages which were found. */ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, pgoff_t end, xa_mark_t tag, unsigned int nr_pages, @@ -1939,6 +1965,8 @@ EXPORT_SYMBOL(find_get_pages_range_tag); * * Like find_get_entries, except we only return entries which are tagged with * @tag. + * + * Return: the number of entries which were found. */ unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start, xa_mark_t tag, unsigned int nr_entries, @@ -2024,6 +2052,10 @@ static void shrink_readahead_size_eio(struct file *filp, * * This is really ugly. But the goto's actually try to clarify some * of the logic when it comes to error handling etc. + * + * Return: + * * total number of bytes copied, including those the were already @written + * * negative error code if nothing was copied */ static ssize_t generic_file_buffered_read(struct kiocb *iocb, struct iov_iter *iter, ssize_t written) @@ -2285,6 +2317,9 @@ out: * * This is the "read_iter()" routine for all filesystems * that can use the page cache directly. + * Return: + * * number of bytes copied, even for partial reads + * * negative error code if nothing was read */ ssize_t generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) @@ -2352,6 +2387,8 @@ EXPORT_SYMBOL(generic_file_read_iter); * * This adds the requested page to the page cache if it isn't already there, * and schedules an I/O to read in its contents from disk. + * + * Return: %0 on success, negative error code otherwise. */ static int page_cache_read(struct file *file, pgoff_t offset, gfp_t gfp_mask) { @@ -2466,6 +2503,8 @@ static void do_async_mmap_readahead(struct vm_area_struct *vma, * has not been released. * * We never return with VM_FAULT_RETRY and a bit from VM_FAULT_ERROR set. + * + * Return: bitwise-OR of %VM_FAULT_ codes. */ vm_fault_t filemap_fault(struct vm_fault *vmf) { @@ -2851,6 +2890,8 @@ out: * not set, try to fill the page and wait for it to become unlocked. * * If the page does not get brought uptodate, return -EIO. + * + * Return: up to date page on success, ERR_PTR() on failure. */ struct page *read_cache_page(struct address_space *mapping, pgoff_t index, @@ -2871,6 +2912,8 @@ EXPORT_SYMBOL(read_cache_page); * any new page allocations done using the specified allocation flags. * * If the page does not get brought uptodate, return -EIO. + * + * Return: up to date page on success, ERR_PTR() on failure. */ struct page *read_cache_page_gfp(struct address_space *mapping, pgoff_t index, @@ -3254,6 +3297,10 @@ EXPORT_SYMBOL(generic_perform_write); * This function does *not* take care of syncing data in case of O_SYNC write. * A caller has to handle it. This is mainly due to the fact that we want to * avoid syncing under i_mutex. + * + * Return: + * * number of bytes written, even for truncated writes + * * negative error code if no data has been written at all */ ssize_t __generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { @@ -3338,6 +3385,10 @@ EXPORT_SYMBOL(__generic_file_write_iter); * This is a wrapper around __generic_file_write_iter() to be used by most * filesystems. It takes care of syncing the file in case of O_SYNC file * and acquires i_mutex as needed. + * Return: + * * negative error code if no data has been written at all of + * vfs_fsync_range() failed for a synchronous write + * * number of bytes written, even for truncated writes */ ssize_t generic_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { @@ -3364,8 +3415,7 @@ EXPORT_SYMBOL(generic_file_write_iter); * @gfp_mask: memory allocation flags (and I/O mode) * * The address_space is to try to release any data against the page - * (presumably at page->private). If the release was successful, return '1'. - * Otherwise return zero. + * (presumably at page->private). * * This may also be called if PG_fscache is set on a page, indicating that the * page is known to the local caching routines. @@ -3373,6 +3423,7 @@ EXPORT_SYMBOL(generic_file_write_iter); * The @gfp_mask argument specifies whether I/O may be performed to release * this page (__GFP_IO), and whether the call may block (__GFP_RECLAIM & __GFP_FS). * + * Return: %1 if the release was successful, otherwise return zero. */ int try_to_release_page(struct page *page, gfp_t gfp_mask) { -- cgit v1.2.2 From 5d3ee42f8f5fa5e7ccc8980878fe6e18a129b9ff Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Tue, 5 Mar 2019 15:49:17 -0800 Subject: mm/shmem: make find_get_pages_range() work for huge page find_get_pages_range() and find_get_pages_range_tag() already correctly increment reference count on head when seeing compound page, but they may still use page index from tail. Page index from tail is always zero, so these functions don't work on huge shmem. This hasn't been a problem because, AFAIK, nobody calls these functions on (huge) shmem. Fix them anyway just in case. Link: http://lkml.kernel.org/r/20190110030838.84446-1-yuzhao@google.com Signed-off-by: Yu Zhao Reviewed-by: William Kucharski Cc: Matthew Wilcox Cc: Amir Goldstein Cc: Dave Chinner Cc: "Darrick J . Wong" Cc: Johannes Weiner Cc: Souptick Joarder Cc: Hugh Dickins Cc: "Kirill A . Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/filemap.c') diff --git a/mm/filemap.c b/mm/filemap.c index ae0022f6106d..a41e01c472f3 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1789,7 +1789,7 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start, pages[ret] = page; if (++ret == nr_pages) { - *start = page->index + 1; + *start = xas.xa_index + 1; goto out; } continue; @@ -1927,7 +1927,7 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, pages[ret] = page; if (++ret == nr_pages) { - *index = page->index + 1; + *index = xas.xa_index + 1; goto out; } continue; -- cgit v1.2.2 From f4b7e272b5c0425915e2115068e0a5a20a3a628e Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Tue, 5 Mar 2019 15:49:39 -0800 Subject: mm: remove zone_lru_lock() function, access ->lru_lock directly We have common pattern to access lru_lock from a page pointer: zone_lru_lock(page_zone(page)) Which is silly, because it unfolds to this: &NODE_DATA(page_to_nid(page))->node_zones[page_zonenum(page)]->zone_pgdat->lru_lock while we can simply do &NODE_DATA(page_to_nid(page))->lru_lock Remove zone_lru_lock() function, since it's only complicate things. Use 'page_pgdat(page)->lru_lock' pattern instead. [aryabinin@virtuozzo.com: a slightly better version of __split_huge_page()] Link: http://lkml.kernel.org/r/20190301121651.7741-1-aryabinin@virtuozzo.com Link: http://lkml.kernel.org/r/20190228083329.31892-2-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin Acked-by: Vlastimil Babka Acked-by: Mel Gorman Cc: Johannes Weiner Cc: Michal Hocko Cc: Rik van Riel Cc: William Kucharski Cc: John Hubbard Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/filemap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/filemap.c') diff --git a/mm/filemap.c b/mm/filemap.c index a41e01c472f3..a3b4021c448f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -98,8 +98,8 @@ * ->swap_lock (try_to_unmap_one) * ->private_lock (try_to_unmap_one) * ->i_pages lock (try_to_unmap_one) - * ->zone_lru_lock(zone) (follow_page->mark_page_accessed) - * ->zone_lru_lock(zone) (check_pte_range->isolate_lru_page) + * ->pgdat->lru_lock (follow_page->mark_page_accessed) + * ->pgdat->lru_lock (check_pte_range->isolate_lru_page) * ->private_lock (page_remove_rmap->set_page_dirty) * ->i_pages lock (page_remove_rmap->set_page_dirty) * bdi.wb->list_lock (page_remove_rmap->set_page_dirty) -- cgit v1.2.2