Remove inclusions of <linux/autoconf.h>
[linux-2.6/linux-mips/linux-dm7025.git] / include / linux / backing-dev.h
blob48a62baace582a5a841436ba2c8fa1bffdd52c4f
1 /*
2 * include/linux/backing-dev.h
4 * low-level device information and state which is propagated up through
5 * to high-level code.
6 */
8 #ifndef _LINUX_BACKING_DEV_H
9 #define _LINUX_BACKING_DEV_H
11 #include <linux/percpu_counter.h>
12 #include <linux/log2.h>
13 #include <linux/proportions.h>
14 #include <asm/atomic.h>
16 struct page;
19 * Bits in backing_dev_info.state
21 enum bdi_state {
22 BDI_pdflush, /* A pdflush thread is working this device */
23 BDI_write_congested, /* The write queue is getting full */
24 BDI_read_congested, /* The read queue is getting full */
25 BDI_unused, /* Available bits start here */
28 typedef int (congested_fn)(void *, int);
30 enum bdi_stat_item {
31 BDI_RECLAIMABLE,
32 BDI_WRITEBACK,
33 NR_BDI_STAT_ITEMS
36 #define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
38 struct backing_dev_info {
39 unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
40 unsigned long state; /* Always use atomic bitops on this */
41 unsigned int capabilities; /* Device capabilities */
42 congested_fn *congested_fn; /* Function pointer if device is md/dm */
43 void *congested_data; /* Pointer to aux data for congested func */
44 void (*unplug_io_fn)(struct backing_dev_info *, struct page *);
45 void *unplug_io_data;
47 struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
49 struct prop_local_percpu completions;
50 int dirty_exceeded;
53 int bdi_init(struct backing_dev_info *bdi);
54 void bdi_destroy(struct backing_dev_info *bdi);
56 static inline void __add_bdi_stat(struct backing_dev_info *bdi,
57 enum bdi_stat_item item, s64 amount)
59 __percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
62 static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
63 enum bdi_stat_item item)
65 __add_bdi_stat(bdi, item, 1);
68 static inline void inc_bdi_stat(struct backing_dev_info *bdi,
69 enum bdi_stat_item item)
71 unsigned long flags;
73 local_irq_save(flags);
74 __inc_bdi_stat(bdi, item);
75 local_irq_restore(flags);
78 static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
79 enum bdi_stat_item item)
81 __add_bdi_stat(bdi, item, -1);
84 static inline void dec_bdi_stat(struct backing_dev_info *bdi,
85 enum bdi_stat_item item)
87 unsigned long flags;
89 local_irq_save(flags);
90 __dec_bdi_stat(bdi, item);
91 local_irq_restore(flags);
94 static inline s64 bdi_stat(struct backing_dev_info *bdi,
95 enum bdi_stat_item item)
97 return percpu_counter_read_positive(&bdi->bdi_stat[item]);
100 static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
101 enum bdi_stat_item item)
103 return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
106 static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
107 enum bdi_stat_item item)
109 s64 sum;
110 unsigned long flags;
112 local_irq_save(flags);
113 sum = __bdi_stat_sum(bdi, item);
114 local_irq_restore(flags);
116 return sum;
120 * maximal error of a stat counter.
122 static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
124 #ifdef CONFIG_SMP
125 return nr_cpu_ids * BDI_STAT_BATCH;
126 #else
127 return 1;
128 #endif
132 * Flags in backing_dev_info::capability
133 * - The first two flags control whether dirty pages will contribute to the
134 * VM's accounting and whether writepages() should be called for dirty pages
135 * (something that would not, for example, be appropriate for ramfs)
136 * - These flags let !MMU mmap() govern direct device mapping vs immediate
137 * copying more easily for MAP_PRIVATE, especially for ROM filesystems
139 #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 /* Dirty pages shouldn't contribute to accounting */
140 #define BDI_CAP_NO_WRITEBACK 0x00000002 /* Don't write pages back */
141 #define BDI_CAP_MAP_COPY 0x00000004 /* Copy can be mapped (MAP_PRIVATE) */
142 #define BDI_CAP_MAP_DIRECT 0x00000008 /* Can be mapped directly (MAP_SHARED) */
143 #define BDI_CAP_READ_MAP 0x00000010 /* Can be mapped for reading */
144 #define BDI_CAP_WRITE_MAP 0x00000020 /* Can be mapped for writing */
145 #define BDI_CAP_EXEC_MAP 0x00000040 /* Can be mapped for execution */
146 #define BDI_CAP_VMFLAGS \
147 (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP)
149 #if defined(VM_MAYREAD) && \
150 (BDI_CAP_READ_MAP != VM_MAYREAD || \
151 BDI_CAP_WRITE_MAP != VM_MAYWRITE || \
152 BDI_CAP_EXEC_MAP != VM_MAYEXEC)
153 #error please change backing_dev_info::capabilities flags
154 #endif
156 extern struct backing_dev_info default_backing_dev_info;
157 void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page);
159 int writeback_acquire(struct backing_dev_info *bdi);
160 int writeback_in_progress(struct backing_dev_info *bdi);
161 void writeback_release(struct backing_dev_info *bdi);
163 static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
165 if (bdi->congested_fn)
166 return bdi->congested_fn(bdi->congested_data, bdi_bits);
167 return (bdi->state & bdi_bits);
170 static inline int bdi_read_congested(struct backing_dev_info *bdi)
172 return bdi_congested(bdi, 1 << BDI_read_congested);
175 static inline int bdi_write_congested(struct backing_dev_info *bdi)
177 return bdi_congested(bdi, 1 << BDI_write_congested);
180 static inline int bdi_rw_congested(struct backing_dev_info *bdi)
182 return bdi_congested(bdi, (1 << BDI_read_congested)|
183 (1 << BDI_write_congested));
186 void clear_bdi_congested(struct backing_dev_info *bdi, int rw);
187 void set_bdi_congested(struct backing_dev_info *bdi, int rw);
188 long congestion_wait(int rw, long timeout);
190 #define bdi_cap_writeback_dirty(bdi) \
191 (!((bdi)->capabilities & BDI_CAP_NO_WRITEBACK))
193 #define bdi_cap_account_dirty(bdi) \
194 (!((bdi)->capabilities & BDI_CAP_NO_ACCT_DIRTY))
196 #define mapping_cap_writeback_dirty(mapping) \
197 bdi_cap_writeback_dirty((mapping)->backing_dev_info)
199 #define mapping_cap_account_dirty(mapping) \
200 bdi_cap_account_dirty((mapping)->backing_dev_info)
203 #endif /* _LINUX_BACKING_DEV_H */