1 /* SPDX-License-Identifier: GPL-2.0 */
46 struct page;
53  * within a page, and of course as the unit of I/O through the
57  * a page (via a page_mapping) and for wrapping bio submission
62 	struct buffer_head *b_this_page;/* circular list of page's buffers */
63 	struct page *b_page;		/* the page this bh is mapped to */
66 	size_t b_size;			/* size of mapping */
67 	char *b_data;			/* pointer to data within the page */
76 	spinlock_t b_uptodate_lock;	/* Used by the first bh in a page, to
78 					 * buffers in the page */
90 	if (!test_bit(BH_##bit, &(bh)->b_state))			\
91 		set_bit(BH_##bit, &(bh)->b_state);			\
95 	clear_bit(BH_##bit, &(bh)->b_state);				\
99 	return test_bit(BH_##bit, &(bh)->b_state);			\
108 	return test_and_set_bit(BH_##bit, &(bh)->b_state);		\
112 	return test_and_clear_bit(BH_##bit, &(bh)->b_state);		\
117  * of the form "mark_buffer_foo()".  These are higher-level functions which
138 #define bh_offset(bh)		((unsigned long)(bh)->b_data & ~PAGE_MASK)
140 /* If we *know* page->private refers to buffer_heads */
141 #define page_buffers(page)					\  argument
143 		BUG_ON(!PagePrivate(page));			\
144 		((struct buffer_head *)page_private(page));	\
146 #define page_has_buffers(page)	PagePrivate(page)  argument
148 void buffer_check_dirty_writeback(struct page *page,
159 		struct page *page, unsigned long offset);
160 int try_to_free_buffers(struct page *);
161 struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
163 void create_empty_buffers(struct page *, unsigned long,
169 /* Things to do with buffers at mapping->private_list */
179 	clean_bdev_aliases(bh->b_bdev, bh->b_blocknr, 1);  in clean_bdev_bh_alias()
186 			unsigned size);
188 				  unsigned size, gfp_t gfp);
191 void __breadahead(struct block_device *, sector_t block, unsigned int size);
192 void __breadahead_gfp(struct block_device *, sector_t block, unsigned int size,
195 				sector_t block, unsigned size, gfp_t gfp);
214  * Generic address_space_operations implementations for buffer_head-backed
217 void block_invalidatepage(struct page *page, unsigned int offset,
219 int block_write_full_page(struct page *page, get_block_t *get_block,
221 int __block_write_full_page(struct inode *inode, struct page *page,
224 int block_read_full_page(struct page*, get_block_t*);
225 int block_is_partially_uptodate(struct page *page, unsigned long from,
228 		unsigned flags, struct page **pagep, get_block_t *get_block);
229 int __block_write_begin(struct page *page, loff_t pos, unsigned len,
233 				struct page *, void *);
236 				struct page *, void *);
237 void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
238 void clean_page_buffers(struct page *page);
240 			unsigned, unsigned, struct page **, void **,
242 int generic_cont_expand_simple(struct inode *inode, loff_t size);
243 int block_commit_write(struct page *page, unsigned from, unsigned to);
246 /* Convert errno to return value from ->page_mkwrite() call */
251 	if (err == -EFAULT || err == -EAGAIN)  in block_page_mkwrite_return()
253 	if (err == -ENOMEM)  in block_page_mkwrite_return()
255 	/* -ENOSPC, -EDQUOT, -EIO ... */  in block_page_mkwrite_return()
261 				struct page **, void **, get_block_t*);
264 				struct page *, void *);
266 int nobh_writepage(struct page *page, get_block_t *get_block,
277         atomic_inc(&bh->b_count);  in get_bh()
283         atomic_dec(&bh->b_count);  in put_bh()
301 	return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);  in sb_bread()
307 	return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0);  in sb_bread_unmovable()
313 	__breadahead(sb->s_bdev, block, sb->s_blocksize);  in sb_breadahead()
319 	__breadahead_gfp(sb->s_bdev, block, sb->s_blocksize, 0);  in sb_breadahead_unmovable()
325 	return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);  in sb_getblk()
332 	return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp);  in sb_getblk_gfp()
338 	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);  in sb_find_get_block()
345 	bh->b_bdev = sb->s_bdev;  in map_bh()
346 	bh->b_blocknr = block;  in map_bh()
347 	bh->b_size = sb->s_blocksize;  in map_bh()
359 	return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));  in trylock_buffer()
371 						   unsigned size)  in getblk_unmovable()  argument
373 	return __getblk_gfp(bdev, block, size, 0);  in getblk_unmovable()
378 					   unsigned size)  in __getblk()  argument
380 	return __getblk_gfp(bdev, block, size, __GFP_MOVABLE);  in __getblk()
384  *  __bread() - reads a specified block and returns the bh
387  *  @size: size (in bytes) to read
390  *  The page cache is allocated from movable area so that it can be migrated.
394 __bread(struct block_device *bdev, sector_t block, unsigned size)  in __bread()  argument
396 	return __bread_gfp(bdev, block, size, __GFP_MOVABLE);  in __bread()
399 extern int __set_page_dirty_buffers(struct page *page);
404 static inline int try_to_free_buffers(struct page *page) { return 1; }  in try_to_free_buffers()  argument