diff options
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 93 |
1 files changed, 67 insertions, 26 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 9f5e323e883e..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) @@ -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, @@ -1765,7 +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; @@ -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) @@ -1837,16 +1861,6 @@ 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; @@ -1872,6 +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, @@ -1911,7 +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; @@ -1949,6 +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, @@ -2034,6 +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) @@ -2295,6 +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) @@ -2362,6 +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) { @@ -2476,6 +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) { @@ -2861,6 +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, @@ -2881,6 +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, @@ -3081,7 +3114,7 @@ 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, @@ -3264,6 +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) { @@ -3348,6 +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) { @@ -3374,8 +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. @@ -3383,6 +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) { |