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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | /* |
| 2 | * include/linux/backing-dev.h |
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| 3 | * |
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| 4 | * low-level device information and state which is propagated up through |
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| 5 | * to high-level code. |
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| 6 | */ |
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| 7 | |||
| 8 | #ifndef _LINUX_BACKING_DEV_H |
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| 9 | #define _LINUX_BACKING_DEV_H |
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| 10 | |||
| 11 | #include <asm/atomic.h> |
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| 12 | |||
| 13 | /* |
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| 14 | * Bits in backing_dev_info.state |
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| 15 | */ |
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| 16 | enum bdi_state { |
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| 17 | BDI_pdflush, /* A pdflush thread is working this device */ |
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| 18 | BDI_write_congested, /* The write queue is getting full */ |
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| 19 | BDI_read_congested, /* The read queue is getting full */ |
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| 20 | BDI_unused, /* Available bits start here */ |
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| 21 | }; |
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| 22 | |||
| 23 | struct backing_dev_info { |
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| 24 | unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */ |
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| 25 | unsigned long state; /* Always use atomic bitops on this */ |
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| 26 | int memory_backed; /* Cannot clean pages with writepage */ |
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| 27 | }; |
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| 28 | |||
| 29 | extern struct backing_dev_info default_backing_dev_info; |
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| 30 | |||
| 31 | int writeback_acquire(struct backing_dev_info *bdi); |
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| 32 | int writeback_in_progress(struct backing_dev_info *bdi); |
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| 33 | void writeback_release(struct backing_dev_info *bdi); |
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| 34 | |||
| 35 | static inline int bdi_read_congested(struct backing_dev_info *bdi) |
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| 36 | { |
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| 37 | return test_bit(BDI_read_congested, &bdi->state); |
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| 38 | } |
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| 39 | |||
| 40 | static inline int bdi_write_congested(struct backing_dev_info *bdi) |
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| 41 | { |
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| 42 | return test_bit(BDI_write_congested, &bdi->state); |
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| 43 | } |
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| 44 | |||
| 45 | #endif /* _LINUX_BACKING_DEV_H */ |