From: Mike Rapoport <rppt@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/dmapool.c | 13 +++++-- mm/filemap.c | 73 +++++++++++++++++++++++++++++++++++------- mm/memory.c | 26 ++++++++++---- mm/mempool.c | 8 ++++ mm/page-writeback.c | 24 +++++++++---- mm/page_alloc.c | 24 ++++++++++--- mm/readahead.c | 2 + mm/slab.c | 14 ++++++++ mm/slab_common.c | 6 +++ mm/truncate.c | 6 ++- mm/util.c | 37 ++++++++++++++------- mm/vmalloc.c | 47 +++++++++++++++++++++------ 12 files changed, 221 insertions(+), 59 deletions(-) --- a/mm/dmapool.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/dmapool.c @@ -114,10 +114,9 @@ static DEVICE_ATTR(pools, 0444, show_poo * @size: size of the blocks in this pool. * @align: alignment requirement for blocks; must be a power of two * @boundary: returned blocks won't cross this power of two boundary - * Context: !in_interrupt() + * Context: not in_interrupt() * - * Returns a dma allocation pool with the requested characteristics, or - * null if one can't be created. Given one of these pools, dma_pool_alloc() + * Given one of these pools, dma_pool_alloc() * may be used to allocate memory. Such memory will all have "consistent" * DMA mappings, accessible by the device and its driver without using * cache flushing primitives. The actual size of blocks allocated may be @@ -127,6 +126,9 @@ static DEVICE_ATTR(pools, 0444, show_poo * cross that size boundary. This is useful for devices which have * addressing restrictions on individual DMA transfers, such as not crossing * boundaries of 4KBytes. + * + * Return: a dma allocation pool with the requested characteristics, or + * %NULL if one can't be created. */ struct dma_pool *dma_pool_create(const char *name, struct device *dev, size_t size, size_t align, size_t boundary) @@ -313,7 +315,7 @@ EXPORT_SYMBOL(dma_pool_destroy); * @mem_flags: GFP_* bitmask * @handle: pointer to dma address of block * - * This returns the kernel virtual address of a currently unused block, + * Return: the kernel virtual address of a currently unused block, * and reports its dma address through the handle. * If such a memory block can't be allocated, %NULL is returned. */ @@ -498,6 +500,9 @@ static int dmam_pool_match(struct device * * Managed dma_pool_create(). DMA pool created with this function is * automatically destroyed on driver detach. + * + * Return: a managed dma allocation pool with the requested + * characteristics, or %NULL if one can't be created. */ struct dma_pool *dmam_pool_create(const char *name, struct device *dev, size_t size, size_t align, size_t allocation) --- a/mm/filemap.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/filemap.c @@ -392,6 +392,8 @@ static int filemap_check_and_keep_errors * 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(st * 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_ * * 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(st * * 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(stru * 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) { --- a/mm/memory.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/memory.c @@ -1504,6 +1504,8 @@ out: * under mm->mmap_sem write-lock, so it can change vma->vm_flags. * Caller must set VM_MIXEDMAP on vma if it wants to call this * function from other places, for example from page-fault handler. + * + * Return: %0 on success, negative error code otherwise. */ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) @@ -1831,7 +1833,9 @@ static inline int remap_p4d_range(struct * @size: size of map area * @prot: page protection flags for this mapping * - * Note: this is only safe if the mm semaphore is held when called. + * Note: this is only safe if the mm semaphore is held when called. + * + * Return: %0 on success, negative error code otherwise. */ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn, unsigned long size, pgprot_t prot) @@ -1904,6 +1908,8 @@ EXPORT_SYMBOL(remap_pfn_range); * * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get * whatever write-combining details or similar. + * + * Return: %0 on success, negative error code otherwise. */ int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) { @@ -2382,12 +2388,13 @@ oom: * * This function handles all that is needed to finish a write page fault in a * shared mapping due to PTE being read-only once the mapped page is prepared. - * It handles locking of PTE and modifying it. The function returns - * VM_FAULT_WRITE on success, 0 when PTE got changed before we acquired PTE - * lock. + * It handles locking of PTE and modifying it. * * The function expects the page to be locked or other protection against * concurrent faults / writeback (such as DAX radix tree locks). + * + * Return: %VM_FAULT_WRITE on success, %0 when PTE got changed before + * we acquired PTE lock. */ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) { @@ -3214,6 +3221,8 @@ static vm_fault_t do_set_pmd(struct vm_f * * Target users are page handler itself and implementations of * vm_ops->map_pages. + * + * Return: %0 on success, %VM_FAULT_ code in case of error. */ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg, struct page *page) @@ -3274,11 +3283,12 @@ vm_fault_t alloc_set_pte(struct vm_fault * This function handles all that is needed to finish a page fault once the * page to fault in is prepared. It handles locking of PTEs, inserts PTE for * given page, adds reverse page mapping, handles memcg charges and LRU - * addition. The function returns 0 on success, VM_FAULT_ code in case of - * error. + * addition. * * The function expects the page to be locked and on success it consumes a * reference of a page being mapped (for the PTE which maps it). + * + * Return: %0 on success, %VM_FAULT_ code in case of error. */ vm_fault_t finish_fault(struct vm_fault *vmf) { @@ -4159,7 +4169,7 @@ EXPORT_SYMBOL(follow_pte_pmd); * * Only IO mappings and raw PFN mappings are allowed. * - * Returns zero and the pfn at @pfn on success, -ve otherwise. + * Return: zero and the pfn at @pfn on success, -ve otherwise. */ int follow_pfn(struct vm_area_struct *vma, unsigned long address, unsigned long *pfn) @@ -4309,6 +4319,8 @@ int __access_remote_vm(struct task_struc * @gup_flags: flags modifying lookup behaviour * * The caller must hold a reference on @mm. + * + * Return: number of bytes copied from source to destination. */ int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags) --- a/mm/mempool.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/mempool.c @@ -222,6 +222,8 @@ EXPORT_SYMBOL(mempool_init_node); * * Like mempool_create(), but initializes the pool in (i.e. embedded in another * structure). + * + * Return: %0 on success, negative error code otherwise. */ int mempool_init(mempool_t *pool, int min_nr, mempool_alloc_t *alloc_fn, mempool_free_t *free_fn, void *pool_data) @@ -245,6 +247,8 @@ EXPORT_SYMBOL(mempool_init); * functions. This function might sleep. Both the alloc_fn() and the free_fn() * functions might sleep - as long as the mempool_alloc() function is not called * from IRQ contexts. + * + * Return: pointer to the created memory pool object or %NULL on error. */ mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn, mempool_free_t *free_fn, void *pool_data) @@ -289,6 +293,8 @@ EXPORT_SYMBOL(mempool_create_node); * Note, the caller must guarantee that no mempool_destroy is called * while this function is running. mempool_alloc() & mempool_free() * might be called (eg. from IRQ contexts) while this function executes. + * + * Return: %0 on success, negative error code otherwise. */ int mempool_resize(mempool_t *pool, int new_min_nr) { @@ -363,6 +369,8 @@ EXPORT_SYMBOL(mempool_resize); * *never* fails when called from process contexts. (it might * fail if called from an IRQ context.) * Note: using __GFP_ZERO is not supported. + * + * Return: pointer to the allocated element or %NULL on error. */ void *mempool_alloc(mempool_t *pool, gfp_t gfp_mask) { --- a/mm/page_alloc.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/page_alloc.c @@ -4816,6 +4816,8 @@ static void *make_alloc_exact(unsigned l * This function is also limited by MAX_ORDER. * * Memory allocated by this function must be released by free_pages_exact(). + * + * Return: pointer to the allocated area or %NULL in case of error. */ void *alloc_pages_exact(size_t size, gfp_t gfp_mask) { @@ -4836,6 +4838,8 @@ EXPORT_SYMBOL(alloc_pages_exact); * * Like alloc_pages_exact(), but try to allocate on node nid first before falling * back. + * + * Return: pointer to the allocated area or %NULL in case of error. */ void * __meminit alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask) { @@ -4869,11 +4873,13 @@ EXPORT_SYMBOL(free_pages_exact); * nr_free_zone_pages - count number of pages beyond high watermark * @offset: The zone index of the highest zone * - * nr_free_zone_pages() counts the number of counts pages which are beyond the + * nr_free_zone_pages() counts the number of pages which are beyond the * high watermark within all zones at or below a given zone index. For each * zone, the number of pages is calculated as: * * nr_free_zone_pages = managed_pages - high_pages + * + * Return: number of pages beyond high watermark. */ static unsigned long nr_free_zone_pages(int offset) { @@ -4900,6 +4906,9 @@ static unsigned long nr_free_zone_pages( * * nr_free_buffer_pages() counts the number of pages which are beyond the high * watermark within ZONE_DMA and ZONE_NORMAL. + * + * Return: number of pages beyond high watermark within ZONE_DMA and + * ZONE_NORMAL. */ unsigned long nr_free_buffer_pages(void) { @@ -4912,6 +4921,8 @@ EXPORT_SYMBOL_GPL(nr_free_buffer_pages); * * nr_free_pagecache_pages() counts the number of pages which are beyond the * high watermark within all zones. + * + * Return: number of pages beyond high watermark within all zones. */ unsigned long nr_free_pagecache_pages(void) { @@ -5358,7 +5369,8 @@ static int node_load[MAX_NUMNODES]; * from each node to each node in the system), and should also prefer nodes * with no CPUs, since presumably they'll have very little allocation pressure * on them otherwise. - * It returns -1 if no node is found. + * + * Return: node id of the found node or %NUMA_NO_NODE if no node is found. */ static int find_next_best_node(int node, nodemask_t *used_node_mask) { @@ -6269,7 +6281,7 @@ unsigned long __init __absent_pages_in_r * @start_pfn: The start PFN to start searching for holes * @end_pfn: The end PFN to stop searching for holes * - * It returns the number of pages frames in memory holes within a range. + * Return: the number of pages frames in memory holes within a range. */ unsigned long __init absent_pages_in_range(unsigned long start_pfn, unsigned long end_pfn) @@ -6826,7 +6838,7 @@ void __init setup_nr_node_ids(void) * model has fine enough granularity to avoid incorrect mapping for the * populated node map. * - * Returns the determined alignment in pfn's. 0 if there is no alignment + * Return: the determined alignment in pfn's. 0 if there is no alignment * requirement (single node). */ unsigned long __init node_map_pfn_alignment(void) @@ -6881,7 +6893,7 @@ static unsigned long __init find_min_pfn /** * find_min_pfn_with_active_regions - Find the minimum PFN registered * - * It returns the minimum PFN based on information provided via + * Return: the minimum PFN based on information provided via * memblock_set_node(). */ unsigned long __init find_min_pfn_with_active_regions(void) @@ -8174,7 +8186,7 @@ static int __alloc_contig_migrate_range( * pageblocks in the range. Once isolated, the pageblocks should not * be modified by others. * - * Returns zero on success or negative error code. On success all + * Return: zero on success or negative error code. On success all * pages which PFN is in [start, end) are allocated for the caller and * need to be freed with free_contig_range(). */ --- a/mm/page-writeback.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/page-writeback.c @@ -270,7 +270,7 @@ static void wb_min_max_ratio(struct bdi_ * node_dirtyable_memory - number of dirtyable pages in a node * @pgdat: the node * - * Returns the node's number of pages potentially available for dirty + * Return: the node's number of pages potentially available for dirty * page cache. This is the base value for the per-node dirty limits. */ static unsigned long node_dirtyable_memory(struct pglist_data *pgdat) @@ -355,7 +355,7 @@ static unsigned long highmem_dirtyable_m /** * global_dirtyable_memory - number of globally dirtyable pages * - * Returns the global number of pages potentially available for dirty + * Return: the global number of pages potentially available for dirty * page cache. This is the base value for the global dirty limits. */ static unsigned long global_dirtyable_memory(void) @@ -470,7 +470,7 @@ void global_dirty_limits(unsigned long * * node_dirty_limit - maximum number of dirty pages allowed in a node * @pgdat: the node * - * Returns the maximum number of dirty pages allowed in a node, based + * Return: the maximum number of dirty pages allowed in a node, based * on the node's dirtyable memory. */ static unsigned long node_dirty_limit(struct pglist_data *pgdat) @@ -495,7 +495,7 @@ static unsigned long node_dirty_limit(st * node_dirty_ok - tells whether a node is within its dirty limits * @pgdat: the node to check * - * Returns %true when the dirty pages in @pgdat are within the node's + * Return: %true when the dirty pages in @pgdat are within the node's * dirty limit, %false if the limit is exceeded. */ bool node_dirty_ok(struct pglist_data *pgdat) @@ -743,9 +743,6 @@ static void mdtc_calc_avail(struct dirty * __wb_calc_thresh - @wb's share of dirty throttling threshold * @dtc: dirty_throttle_context of interest * - * Returns @wb's dirty limit in pages. The term "dirty" in the context of - * dirty balancing includes all PG_dirty, PG_writeback and NFS unstable pages. - * * Note that balance_dirty_pages() will only seriously take it as a hard limit * when sleeping max_pause per page is not enough to keep the dirty pages under * control. For example, when the device is completely stalled due to some error @@ -759,6 +756,9 @@ static void mdtc_calc_avail(struct dirty * * The wb's share of dirty limit will be adapting to its throughput and * bounded by the bdi->min_ratio and/or bdi->max_ratio parameters, if set. + * + * Return: @wb's dirty limit in pages. The term "dirty" in the context of + * dirty balancing includes all PG_dirty, PG_writeback and NFS unstable pages. */ static unsigned long __wb_calc_thresh(struct dirty_throttle_control *dtc) { @@ -1918,7 +1918,9 @@ EXPORT_SYMBOL(balance_dirty_pages_rateli * @wb: bdi_writeback of interest * * Determines whether background writeback should keep writing @wb or it's - * clean enough. Returns %true if writeback should continue. + * clean enough. + * + * Return: %true if writeback should continue. */ bool wb_over_bg_thresh(struct bdi_writeback *wb) { @@ -2147,6 +2149,8 @@ EXPORT_SYMBOL(tag_pages_for_writeback); * lock/page writeback access order inversion - we should only ever lock * multiple pages in ascending page->index order, and looping back to the start * of the file violates that rule and causes deadlocks. + * + * Return: %0 on success, negative error code otherwise */ int write_cache_pages(struct address_space *mapping, struct writeback_control *wbc, writepage_t writepage, @@ -2305,6 +2309,8 @@ static int __writepage(struct page *page * * This is a library function, which implements the writepages() * address_space_operation. + * + * Return: %0 on success, negative error code otherwise */ int generic_writepages(struct address_space *mapping, struct writeback_control *wbc) @@ -2351,6 +2357,8 @@ int do_writepages(struct address_space * * * Note that the mapping's AS_EIO/AS_ENOSPC flags will be cleared when this * function returns. + * + * Return: %0 on success, negative error code otherwise */ int write_one_page(struct page *page) { --- a/mm/readahead.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/readahead.c @@ -81,6 +81,8 @@ static void read_cache_pages_invalidate_ * @data: private data for the callback routine. * * Hides the details of the LRU cache etc from the filesystems. + * + * Returns: %0 on success, error return by @filler otherwise */ int read_cache_pages(struct address_space *mapping, struct list_head *pages, int (*filler)(void *, struct page *), void *data) --- a/mm/slab.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/slab.c @@ -1727,6 +1727,8 @@ static void slabs_destroy(struct kmem_ca * This could be made much more intelligent. For now, try to avoid using * high order pages for slabs. When the gfp() functions are more friendly * towards high-order requests, this should be changed. + * + * Return: number of left-over bytes in a slab */ static size_t calculate_slab_order(struct kmem_cache *cachep, size_t size, slab_flags_t flags) @@ -1975,6 +1977,8 @@ static bool set_on_slab_cache(struct kme * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware * cacheline. This can be beneficial if you're counting cycles as closely * as davem. + * + * Return: a pointer to the created cache or %NULL in case of error */ int __kmem_cache_create(struct kmem_cache *cachep, slab_flags_t flags) { @@ -3542,6 +3546,8 @@ void ___cache_free(struct kmem_cache *ca * * Allocate an object from this cache. The flags are only relevant * if the cache has no available objects. + * + * Return: pointer to the new object or %NULL in case of error */ void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) { @@ -3631,6 +3637,8 @@ EXPORT_SYMBOL(kmem_cache_alloc_trace); * node, which can improve the performance for cpu bound structures. * * Fallback to other node is possible if __GFP_THISNODE is not set. + * + * Return: pointer to the new object or %NULL in case of error */ void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) { @@ -3699,6 +3707,8 @@ EXPORT_SYMBOL(__kmalloc_node_track_calle * @size: how many bytes of memory are required. * @flags: the type of memory to allocate (see kmalloc). * @caller: function caller for debug tracking of the caller + * + * Return: pointer to the allocated memory or %NULL in case of error */ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, unsigned long caller) @@ -4164,6 +4174,8 @@ void slabinfo_show_stats(struct seq_file * @buffer: user buffer * @count: data length * @ppos: unused + * + * Return: %0 on success, negative error code otherwise. */ ssize_t slabinfo_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) @@ -4457,6 +4469,8 @@ void __check_heap_object(const void *ptr * The caller must guarantee that objp points to a valid object previously * allocated with either kmalloc() or kmem_cache_alloc(). The object * must not be freed during the duration of the call. + * + * Return: size of the actual memory used by @objp in bytes */ size_t ksize(const void *objp) { --- a/mm/slab_common.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/slab_common.c @@ -939,6 +939,8 @@ EXPORT_SYMBOL(kmem_cache_destroy); * * Releases as many slabs as possible for a cache. * To help debugging, a zero exit status indicates all slabs were released. + * + * Return: %0 if all slabs were released, non-zero otherwise */ int kmem_cache_shrink(struct kmem_cache *cachep) { @@ -1528,6 +1530,8 @@ static __always_inline void *__do_kreall * This function is like krealloc() except it never frees the originally * allocated buffer. Use this if you don't want to free the buffer immediately * like, for example, with RCU. + * + * Return: pointer to the allocated memory or %NULL in case of error */ void *__krealloc(const void *p, size_t new_size, gfp_t flags) { @@ -1549,6 +1553,8 @@ EXPORT_SYMBOL(__krealloc); * lesser of the new and old sizes. If @p is %NULL, krealloc() * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a * %NULL pointer, the object pointed to is freed. + * + * Return: pointer to the allocated memory or %NULL in case of error */ void *krealloc(const void *p, size_t new_size, gfp_t flags) { --- a/mm/truncate.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/truncate.c @@ -539,6 +539,8 @@ EXPORT_SYMBOL(truncate_inode_pages_final * invalidate_mapping_pages() will not block on IO activity. It will not * invalidate pages which are dirty, locked, under writeback or mapped into * pagetables. + * + * Return: the number of the pages that were invalidated */ unsigned long invalidate_mapping_pages(struct address_space *mapping, pgoff_t start, pgoff_t end) @@ -664,7 +666,7 @@ static int do_launder_page(struct addres * Any pages which are found to be mapped into pagetables are unmapped prior to * invalidation. * - * Returns -EBUSY if any pages could not be invalidated. + * Return: -EBUSY if any pages could not be invalidated. */ int invalidate_inode_pages2_range(struct address_space *mapping, pgoff_t start, pgoff_t end) @@ -761,7 +763,7 @@ EXPORT_SYMBOL_GPL(invalidate_inode_pages * Any pages which are found to be mapped into pagetables are unmapped prior to * invalidation. * - * Returns -EBUSY if any pages could not be invalidated. + * Return: -EBUSY if any pages could not be invalidated. */ int invalidate_inode_pages2(struct address_space *mapping) { --- a/mm/util.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/util.c @@ -36,6 +36,8 @@ EXPORT_SYMBOL(kfree_const); * kstrdup - allocate space for and copy an existing string * @s: the string to duplicate * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Return: newly allocated copy of @s or %NULL in case of error */ char *kstrdup(const char *s, gfp_t gfp) { @@ -58,9 +60,10 @@ EXPORT_SYMBOL(kstrdup); * @s: the string to duplicate * @gfp: the GFP mask used in the kmalloc() call when allocating memory * - * Function returns source string if it is in .rodata section otherwise it - * fallbacks to kstrdup. - * Strings allocated by kstrdup_const should be freed by kfree_const. + * Note: Strings allocated by kstrdup_const should be freed by kfree_const. + * + * Return: source string if it is in .rodata section otherwise + * fallback to kstrdup. */ const char *kstrdup_const(const char *s, gfp_t gfp) { @@ -78,6 +81,8 @@ EXPORT_SYMBOL(kstrdup_const); * @gfp: the GFP mask used in the kmalloc() call when allocating memory * * Note: Use kmemdup_nul() instead if the size is known exactly. + * + * Return: newly allocated copy of @s or %NULL in case of error */ char *kstrndup(const char *s, size_t max, gfp_t gfp) { @@ -103,6 +108,8 @@ EXPORT_SYMBOL(kstrndup); * @src: memory region to duplicate * @len: memory region length * @gfp: GFP mask to use + * + * Return: newly allocated copy of @src or %NULL in case of error */ void *kmemdup(const void *src, size_t len, gfp_t gfp) { @@ -120,6 +127,9 @@ EXPORT_SYMBOL(kmemdup); * @s: The data to stringify * @len: The size of the data * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Return: newly allocated copy of @s with NUL-termination or %NULL in + * case of error */ char *kmemdup_nul(const char *s, size_t len, gfp_t gfp) { @@ -143,7 +153,7 @@ EXPORT_SYMBOL(kmemdup_nul); * @src: source address in user space * @len: number of bytes to copy * - * Returns an ERR_PTR() on failure. Result is physically + * Return: an ERR_PTR() on failure. Result is physically * contiguous, to be freed by kfree(). */ void *memdup_user(const void __user *src, size_t len) @@ -169,7 +179,7 @@ EXPORT_SYMBOL(memdup_user); * @src: source address in user space * @len: number of bytes to copy * - * Returns an ERR_PTR() on failure. Result may be not + * Return: an ERR_PTR() on failure. Result may be not * physically contiguous. Use kvfree() to free. */ void *vmemdup_user(const void __user *src, size_t len) @@ -193,6 +203,8 @@ EXPORT_SYMBOL(vmemdup_user); * strndup_user - duplicate an existing string from user space * @s: The string to duplicate * @n: Maximum number of bytes to copy, including the trailing NUL. + * + * Return: newly allocated copy of @s or %NULL in case of error */ char *strndup_user(const char __user *s, long n) { @@ -224,7 +236,7 @@ EXPORT_SYMBOL(strndup_user); * @src: source address in user space * @len: number of bytes to copy * - * Returns an ERR_PTR() on failure. + * Return: an ERR_PTR() on failure. */ void *memdup_user_nul(const void __user *src, size_t len) { @@ -310,10 +322,6 @@ EXPORT_SYMBOL_GPL(__get_user_pages_fast) * @pages: array that receives pointers to the pages pinned. * Should be at least nr_pages long. * - * Returns number of pages pinned. This may be fewer than the number - * requested. If nr_pages is 0 or negative, returns 0. If no pages - * were pinned, returns -errno. - * * get_user_pages_fast provides equivalent functionality to get_user_pages, * operating on current and current->mm, with force=0 and vma=NULL. However * unlike get_user_pages, it must be called without mmap_sem held. @@ -325,6 +333,10 @@ EXPORT_SYMBOL_GPL(__get_user_pages_fast) * pages have to be faulted in, it may turn out to be slightly slower so * callers need to carefully consider what to use. On many architectures, * get_user_pages_fast simply falls back to get_user_pages. + * + * Return: number of pages pinned. This may be fewer than the number + * requested. If nr_pages is 0 or negative, returns 0. If no pages + * were pinned, returns -errno. */ int __weak get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) @@ -386,6 +398,8 @@ EXPORT_SYMBOL(vm_mmap); * * Please note that any use of gfp flags outside of GFP_KERNEL is careful to not * fall back to vmalloc. + * + * Return: pointer to the allocated memory of %NULL in case of failure */ void *kvmalloc_node(size_t size, gfp_t flags, int node) { @@ -729,7 +743,8 @@ error: * @buffer: the buffer to copy to. * @buflen: the length of the buffer. Larger cmdline values are truncated * to this length. - * Returns the size of the cmdline field copied. Note that the copy does + * + * Return: the size of the cmdline field copied. Note that the copy does * not guarantee an ending NULL byte. */ int get_cmdline(struct task_struct *task, char *buffer, int buflen) --- a/mm/vmalloc.c~docs-core-api-mm-fix-return-value-descriptions-in-mm +++ a/mm/vmalloc.c @@ -844,7 +844,7 @@ static void *vmap_block_vaddr(unsigned l * @order: how many 2^order pages should be occupied in newly allocated block * @gfp_mask: flags for the page level allocator * - * Returns: virtual address in a newly allocated block or ERR_PTR(-errno) + * Return: virtual address in a newly allocated block or ERR_PTR(-errno) */ static void *new_vmap_block(unsigned int order, gfp_t gfp_mask) { @@ -1433,6 +1433,8 @@ struct vm_struct *__get_vm_area_caller(u * Search an area of @size in the kernel virtual mapping area, * and reserved it for out purposes. Returns the area descriptor * on success or %NULL on failure. + * + * Return: the area descriptor on success or %NULL on failure. */ struct vm_struct *get_vm_area(unsigned long size, unsigned long flags) { @@ -1455,6 +1457,8 @@ struct vm_struct *get_vm_area_caller(uns * Search for the kernel VM area starting at @addr, and return it. * It is up to the caller to do all required locking to keep the returned * pointer valid. + * + * Return: pointer to the found area or %NULL on faulure */ struct vm_struct *find_vm_area(const void *addr) { @@ -1474,6 +1478,8 @@ struct vm_struct *find_vm_area(const voi * Search for the kernel VM area starting at @addr, and remove it. * This function returns the found VM area, but using it is NOT safe * on SMP machines, except for its size or flags. + * + * Return: pointer to the found area or %NULL on faulure */ struct vm_struct *remove_vm_area(const void *addr) { @@ -1636,6 +1642,8 @@ EXPORT_SYMBOL(vunmap); * * Maps @count pages from @pages into contiguous kernel virtual * space. + * + * Return: the address of the area or %NULL on failure */ void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) @@ -1739,6 +1747,8 @@ fail: * Allocate enough pages to cover @size from the page level * allocator with @gfp_mask flags. Map them into contiguous * kernel virtual space, using a pagetable protection of @prot. + * + * Return: the address of the area or %NULL on failure */ void *__vmalloc_node_range(unsigned long size, unsigned long align, unsigned long start, unsigned long end, gfp_t gfp_mask, @@ -1806,6 +1816,8 @@ EXPORT_SYMBOL_GPL(__vmalloc_node_range); * * Any use of gfp flags outside of GFP_KERNEL should be consulted * with mm people. + * + * Return: pointer to the allocated memory or %NULL on error */ static void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask, pgprot_t prot, @@ -1845,6 +1857,8 @@ void *__vmalloc_node_flags_caller(unsign * * For tight control over page level allocator and protection flags * use __vmalloc() instead. + * + * Return: pointer to the allocated memory or %NULL on error */ void *vmalloc(unsigned long size) { @@ -1863,6 +1877,8 @@ EXPORT_SYMBOL(vmalloc); * * For tight control over page level allocator and protection flags * use __vmalloc() instead. + * + * Return: pointer to the allocated memory or %NULL on error */ void *vzalloc(unsigned long size) { @@ -1877,6 +1893,8 @@ EXPORT_SYMBOL(vzalloc); * * The resulting memory area is zeroed so it can be mapped to userspace * without leaking data. + * + * Return: pointer to the allocated memory or %NULL on error */ void *vmalloc_user(unsigned long size) { @@ -1897,6 +1915,8 @@ EXPORT_SYMBOL(vmalloc_user); * * For tight control over page level allocator and protection flags * use __vmalloc() instead. + * + * Return: pointer to the allocated memory or %NULL on error */ void *vmalloc_node(unsigned long size, int node) { @@ -1916,6 +1936,8 @@ EXPORT_SYMBOL(vmalloc_node); * * For tight control over page level allocator and protection flags * use __vmalloc_node() instead. + * + * Return: pointer to the allocated memory or %NULL on error */ void *vzalloc_node(unsigned long size, int node) { @@ -1934,6 +1956,8 @@ EXPORT_SYMBOL(vzalloc_node); * * For tight control over page level allocator and protection flags * use __vmalloc() instead. + * + * Return: pointer to the allocated memory or %NULL on error */ void *vmalloc_exec(unsigned long size) { @@ -1959,6 +1983,8 @@ void *vmalloc_exec(unsigned long size) * * Allocate enough 32bit PA addressable pages to cover @size from the * page level allocator and map them into contiguous kernel virtual space. + * + * Return: pointer to the allocated memory or %NULL on error */ void *vmalloc_32(unsigned long size) { @@ -1973,6 +1999,8 @@ EXPORT_SYMBOL(vmalloc_32); * * The resulting memory area is 32bit addressable and zeroed so it can be * mapped to userspace without leaking data. + * + * Return: pointer to the allocated memory or %NULL on error */ void *vmalloc_32_user(unsigned long size) { @@ -2070,10 +2098,6 @@ static int aligned_vwrite(char *buf, cha * @addr: vm address. * @count: number of bytes to be read. * - * Returns # of bytes which addr and buf should be increased. - * (same number to @count). Returns 0 if [addr...addr+count) doesn't - * includes any intersect with alive vmalloc area. - * * This function checks that addr is a valid vmalloc'ed area, and * copy data from that area to a given buffer. If the given memory range * of [addr...addr+count) includes some valid address, data is copied to @@ -2087,6 +2111,10 @@ static int aligned_vwrite(char *buf, cha * should know vmalloc() area is valid and can use memcpy(). * This is for routines which have to access vmalloc area without * any informaion, as /dev/kmem. + * + * Return: number of bytes for which addr and buf should be increased + * (same number as @count) or %0 if [addr...addr+count) doesn't + * include any intersection with valid vmalloc area */ long vread(char *buf, char *addr, unsigned long count) { @@ -2149,11 +2177,6 @@ finished: * @addr: vm address. * @count: number of bytes to be read. * - * Returns # of bytes which addr and buf should be incresed. - * (same number to @count). - * If [addr...addr+count) doesn't includes any intersect with valid - * vmalloc area, returns 0. - * * This function checks that addr is a valid vmalloc'ed area, and * copy data from a buffer to the given addr. If specified range of * [addr...addr+count) includes some valid address, data is copied from @@ -2167,6 +2190,10 @@ finished: * should know vmalloc() area is valid and can use memcpy(). * This is for routines which have to access vmalloc area without * any informaion, as /dev/kmem. + * + * Return: number of bytes for which addr and buf should be + * increased (same number as @count) or %0 if [addr...addr+count) + * doesn't include any intersection with valid vmalloc area */ long vwrite(char *buf, char *addr, unsigned long count) { _
