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Subject[PATCH 3/3] docs/core-api/mm: fix return value descriptions in mm/
Date
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.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
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(-)

diff --git a/mm/dmapool.c b/mm/dmapool.c
index 6d4b97e..76a1600 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -114,10 +114,9 @@ static DEVICE_ATTR(pools, 0444, show_pools, NULL);
* @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_pools, NULL);
* 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 *dev, void *res, void *match_data)
*
* 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)
diff --git a/mm/filemap.c b/mm/filemap.c
index 9f5e323..216be92 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.
+ *
+ * Returns: %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.
+ *
+ * Returns: %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.
+ *
+ * Returns: %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 @@ static int __add_to_page_cache_locked(struct page *page,
*
* 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.
+ *
+ * Returns: %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 @@ unsigned find_get_entries(struct address_space *mapping,
* 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 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
* 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)
@@ -1872,6 +1896,8 @@ 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,
@@ -1949,6 +1975,8 @@ 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 +2062,10 @@ 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 +2327,9 @@ static ssize_t generic_file_buffered_read(struct kiocb *iocb,
*
* 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 +2397,8 @@ 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.
+ *
+ * Returns: %0 on success, negative error code otherwise.
*/
static int page_cache_read(struct file *file, pgoff_t offset, gfp_t gfp_mask)
{
@@ -2476,6 +2513,8 @@ 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 +2900,8 @@ static struct page *do_read_cache_page(struct address_space *mapping,
* 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 +2922,8 @@ 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,
@@ -3264,6 +3307,10 @@ 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 +3395,10 @@ 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 +3425,7 @@ 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 +3433,7 @@ 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)
{
diff --git a/mm/memory.c b/mm/memory.c
index a52663c..1691648e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1503,6 +1503,8 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr,
* 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)
@@ -1830,7 +1832,9 @@ static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd,
* @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)
@@ -1903,6 +1907,8 @@ 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)
{
@@ -2381,12 +2387,13 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
*
* 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)
{
@@ -3179,6 +3186,8 @@ static vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
*
* 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)
@@ -3239,11 +3248,12 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
* 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)
{
@@ -4128,7 +4138,7 @@ 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)
@@ -4278,6 +4288,8 @@ int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
* @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)
diff --git a/mm/mempool.c b/mm/mempool.c
index 0ef8cc8..85efab3 100644
--- a/mm/mempool.c
+++ b/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)
{
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7d10104..9f61dfe 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -270,7 +270,7 @@ static void wb_min_max_ratio(struct bdi_writeback *wb,
* 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_memory(unsigned long total)
/**
* 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 *pbackground, unsigned long *pdirty)
* 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(struct pglist_data *pgdat)
* 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_throttle_control *mdtc,
* __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_throttle_control *mdtc,
*
* 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_ratelimited);
* @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, struct writeback_control *wbc,
*
* 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 *mapping, struct writeback_control *wbc)
*
* 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)
{
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cde5dac..259bb76 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4743,6 +4743,8 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
* 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)
{
@@ -4763,6 +4765,8 @@ 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)
{
@@ -4796,11 +4800,13 @@ 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)
{
@@ -4827,6 +4833,9 @@ static unsigned long nr_free_zone_pages(int offset)
*
* 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)
{
@@ -4839,6 +4848,8 @@ 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)
{
@@ -5285,7 +5296,8 @@ 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)
{
@@ -6208,7 +6220,7 @@ unsigned long __init __absent_pages_in_range(int nid,
* @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)
@@ -6758,7 +6770,7 @@ 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)
@@ -6813,7 +6825,7 @@ static unsigned long __init find_min_pfn_for_node(int nid)
/**
* 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)
@@ -8106,7 +8118,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
* 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().
*/
diff --git a/mm/readahead.c b/mm/readahead.c
index 1ae1652..a459365 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -81,6 +81,8 @@ static void read_cache_pages_invalidate_pages(struct address_space *mapping,
* @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)
diff --git a/mm/slab.c b/mm/slab.c
index 73fe23e..3d1969d 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1725,6 +1725,8 @@ static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list)
* 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)
@@ -1973,6 +1975,8 @@ static bool set_on_slab_cache(struct kmem_cache *cachep,
* %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)
{
@@ -3533,6 +3537,8 @@ void ___cache_free(struct kmem_cache *cachep, void *objp,
*
* 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)
{
@@ -3623,6 +3629,8 @@ 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)
{
@@ -3692,6 +3700,8 @@ EXPORT_SYMBOL(__kmalloc_node_track_caller);
* @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)
@@ -4157,6 +4167,8 @@ void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
* @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)
@@ -4448,6 +4460,8 @@ void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
* 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)
{
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 81732d0..edd1368 100644
--- a/mm/slab_common.c
+++ b/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)
{
@@ -1527,6 +1529,8 @@ static __always_inline void *__do_krealloc(const void *p, size_t new_size,
* 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)
{
@@ -1548,6 +1552,8 @@ 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)
{
diff --git a/mm/truncate.c b/mm/truncate.c
index 798e7cc..b7d3c99 100644
--- a/mm/truncate.c
+++ b/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 address_space *mapping, struct page *page)
* 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_pages2_range);
* 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)
{
diff --git a/mm/util.c b/mm/util.c
index 4df23d6..6aa1f74 100644
--- a/mm/util.c
+++ b/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 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
* @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)
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 215961c..a748165 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -840,7 +840,7 @@ static void *vmap_block_vaddr(unsigned long va_start, unsigned long pages_off)
* @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)
{
@@ -1429,6 +1429,8 @@ struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
* 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)
{
@@ -1451,6 +1453,8 @@ struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
* 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)
{
@@ -1470,6 +1474,8 @@ struct vm_struct *find_vm_area(const void *addr)
* 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)
{
@@ -1626,6 +1632,8 @@ 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)
@@ -1729,6 +1737,8 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
* 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,
@@ -1787,6 +1797,8 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align,
*
* 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,
@@ -1826,6 +1838,8 @@ void *__vmalloc_node_flags_caller(unsigned long size, int node, gfp_t flags,
*
* 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)
{
@@ -1844,6 +1858,8 @@ 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)
{
@@ -1858,6 +1874,8 @@ 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)
{
@@ -1886,6 +1904,8 @@ 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)
{
@@ -1905,6 +1925,8 @@ 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)
{
@@ -1923,6 +1945,8 @@ 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)
{
@@ -1948,6 +1972,8 @@ 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)
{
@@ -1962,6 +1988,8 @@ 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)
{
@@ -2065,10 +2093,6 @@ static int aligned_vwrite(char *buf, char *addr, unsigned long count)
* @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
@@ -2082,6 +2106,10 @@ static int aligned_vwrite(char *buf, char *addr, unsigned long count)
* 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)
{
@@ -2144,11 +2172,6 @@ long vread(char *buf, char *addr, unsigned long count)
* @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
@@ -2162,6 +2185,10 @@ long vread(char *buf, char *addr, unsigned long count)
* 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)
{
--
2.7.4
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