1 files changed, 321 insertions, 0 deletions

diff --git a/kernel/include/linux/backing-dev.h b/kernel/include/linux/backing-dev.h
new file mode 100644
index 000000000..d87d8eced
--- /dev/null
+++ b/kernel/include/linux/backing-dev.h
@@ -0,0 +1,321 @@
+/*
+ * include/linux/backing-dev.h
+ *
+ * low-level device information and state which is propagated up through
+ * to high-level code.
+ */
+
+#ifndef _LINUX_BACKING_DEV_H
+#define _LINUX_BACKING_DEV_H
+
+#include <linux/percpu_counter.h>
+#include <linux/log2.h>
+#include <linux/flex_proportions.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/writeback.h>
+#include <linux/atomic.h>
+#include <linux/sysctl.h>
+#include <linux/workqueue.h>
+
+struct page;
+struct device;
+struct dentry;
+
+/*
+ * Bits in backing_dev_info.state
+ */
+enum bdi_state {
+	BDI_async_congested,	/* The async (write) queue is getting full */
+	BDI_sync_congested,	/* The sync queue is getting full */
+	BDI_registered,		/* bdi_register() was done */
+	BDI_writeback_running,	/* Writeback is in progress */
+};
+
+typedef int (congested_fn)(void *, int);
+
+enum bdi_stat_item {
+	BDI_RECLAIMABLE,
+	BDI_WRITEBACK,
+	BDI_DIRTIED,
+	BDI_WRITTEN,
+	NR_BDI_STAT_ITEMS
+};
+
+#define BDI_STAT_BATCH (8*(1+ilog2(nr_cpu_ids)))
+
+struct bdi_writeback {
+	struct backing_dev_info *bdi;	/* our parent bdi */
+
+	unsigned long last_old_flush;	/* last old data flush */
+
+	struct delayed_work dwork;	/* work item used for writeback */
+	struct list_head b_dirty;	/* dirty inodes */
+	struct list_head b_io;		/* parked for writeback */
+	struct list_head b_more_io;	/* parked for more writeback */
+	struct list_head b_dirty_time;	/* time stamps are dirty */
+	spinlock_t list_lock;		/* protects the b_* lists */
+};
+
+struct backing_dev_info {
+	struct list_head bdi_list;
+	unsigned long ra_pages;	/* max readahead in PAGE_CACHE_SIZE units */
+	unsigned long state;	/* Always use atomic bitops on this */
+	unsigned int capabilities; /* Device capabilities */
+	congested_fn *congested_fn; /* Function pointer if device is md/dm */
+	void *congested_data;	/* Pointer to aux data for congested func */
+
+	char *name;
+
+	struct percpu_counter bdi_stat[NR_BDI_STAT_ITEMS];
+
+	unsigned long bw_time_stamp;	/* last time write bw is updated */
+	unsigned long dirtied_stamp;
+	unsigned long written_stamp;	/* pages written at bw_time_stamp */
+	unsigned long write_bandwidth;	/* the estimated write bandwidth */
+	unsigned long avg_write_bandwidth; /* further smoothed write bw */
+
+	/*
+	 * The base dirty throttle rate, re-calculated on every 200ms.
+	 * All the bdi tasks' dirty rate will be curbed under it.
+	 * @dirty_ratelimit tracks the estimated @balanced_dirty_ratelimit
+	 * in small steps and is much more smooth/stable than the latter.
+	 */
+	unsigned long dirty_ratelimit;
+	unsigned long balanced_dirty_ratelimit;
+
+	struct fprop_local_percpu completions;
+	int dirty_exceeded;
+
+	unsigned int min_ratio;
+	unsigned int max_ratio, max_prop_frac;
+
+	struct bdi_writeback wb;  /* default writeback info for this bdi */
+	spinlock_t wb_lock;	  /* protects work_list & wb.dwork scheduling */
+
+	struct list_head work_list;
+
+	struct device *dev;
+
+	struct timer_list laptop_mode_wb_timer;
+
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *debug_dir;
+	struct dentry *debug_stats;
+#endif
+};
+
+struct backing_dev_info *inode_to_bdi(struct inode *inode);
+
+int __must_check bdi_init(struct backing_dev_info *bdi);
+void bdi_destroy(struct backing_dev_info *bdi);
+
+__printf(3, 4)
+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
+		const char *fmt, ...);
+int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);
+int __must_check bdi_setup_and_register(struct backing_dev_info *, char *);
+void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
+			enum wb_reason reason);
+void bdi_start_background_writeback(struct backing_dev_info *bdi);
+void bdi_writeback_workfn(struct work_struct *work);
+int bdi_has_dirty_io(struct backing_dev_info *bdi);
+void bdi_wakeup_thread_delayed(struct backing_dev_info *bdi);
+
+extern spinlock_t bdi_lock;
+extern struct list_head bdi_list;
+
+extern struct workqueue_struct *bdi_wq;
+
+static inline int wb_has_dirty_io(struct bdi_writeback *wb)
+{
+	return !list_empty(&wb->b_dirty) ||
+	       !list_empty(&wb->b_io) ||
+	       !list_empty(&wb->b_more_io);
+}
+
+static inline void __add_bdi_stat(struct backing_dev_info *bdi,
+		enum bdi_stat_item item, s64 amount)
+{
+	__percpu_counter_add(&bdi->bdi_stat[item], amount, BDI_STAT_BATCH);
+}
+
+static inline void __inc_bdi_stat(struct backing_dev_info *bdi,
+		enum bdi_stat_item item)
+{
+	__add_bdi_stat(bdi, item, 1);
+}
+
+static inline void inc_bdi_stat(struct backing_dev_info *bdi,
+		enum bdi_stat_item item)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__inc_bdi_stat(bdi, item);
+	local_irq_restore(flags);
+}
+
+static inline void __dec_bdi_stat(struct backing_dev_info *bdi,
+		enum bdi_stat_item item)
+{
+	__add_bdi_stat(bdi, item, -1);
+}
+
+static inline void dec_bdi_stat(struct backing_dev_info *bdi,
+		enum bdi_stat_item item)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	__dec_bdi_stat(bdi, item);
+	local_irq_restore(flags);
+}
+
+static inline s64 bdi_stat(struct backing_dev_info *bdi,
+		enum bdi_stat_item item)
+{
+	return percpu_counter_read_positive(&bdi->bdi_stat[item]);
+}
+
+static inline s64 __bdi_stat_sum(struct backing_dev_info *bdi,
+		enum bdi_stat_item item)
+{
+	return percpu_counter_sum_positive(&bdi->bdi_stat[item]);
+}
+
+static inline s64 bdi_stat_sum(struct backing_dev_info *bdi,
+		enum bdi_stat_item item)
+{
+	s64 sum;
+	unsigned long flags;
+
+	local_irq_save(flags);
+	sum = __bdi_stat_sum(bdi, item);
+	local_irq_restore(flags);
+
+	return sum;
+}
+
+extern void bdi_writeout_inc(struct backing_dev_info *bdi);
+
+/*
+ * maximal error of a stat counter.
+ */
+static inline unsigned long bdi_stat_error(struct backing_dev_info *bdi)
+{
+#ifdef CONFIG_SMP
+	return nr_cpu_ids * BDI_STAT_BATCH;
+#else
+	return 1;
+#endif
+}
+
+int bdi_set_min_ratio(struct backing_dev_info *bdi, unsigned int min_ratio);
+int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
+
+/*
+ * Flags in backing_dev_info::capability
+ *
+ * The first three flags control whether dirty pages will contribute to the
+ * VM's accounting and whether writepages() should be called for dirty pages
+ * (something that would not, for example, be appropriate for ramfs)
+ *
+ * WARNING: these flags are closely related and should not normally be
+ * used separately.  The BDI_CAP_NO_ACCT_AND_WRITEBACK combines these
+ * three flags into a single convenience macro.
+ *
+ * BDI_CAP_NO_ACCT_DIRTY:  Dirty pages shouldn't contribute to accounting
+ * BDI_CAP_NO_WRITEBACK:   Don't write pages back
+ * BDI_CAP_NO_ACCT_WB:     Don't automatically account writeback pages
+ * BDI_CAP_STRICTLIMIT:    Keep number of dirty pages below bdi threshold.
+ */
+#define BDI_CAP_NO_ACCT_DIRTY	0x00000001
+#define BDI_CAP_NO_WRITEBACK	0x00000002
+#define BDI_CAP_NO_ACCT_WB	0x00000004
+#define BDI_CAP_STABLE_WRITES	0x00000008
+#define BDI_CAP_STRICTLIMIT	0x00000010
+
+#define BDI_CAP_NO_ACCT_AND_WRITEBACK \
+	(BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB)
+
+extern struct backing_dev_info noop_backing_dev_info;
+
+int writeback_in_progress(struct backing_dev_info *bdi);
+
+static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
+{
+	if (bdi->congested_fn)
+		return bdi->congested_fn(bdi->congested_data, bdi_bits);
+	return (bdi->state & bdi_bits);
+}
+
+static inline int bdi_read_congested(struct backing_dev_info *bdi)
+{
+	return bdi_congested(bdi, 1 << BDI_sync_congested);
+}
+
+static inline int bdi_write_congested(struct backing_dev_info *bdi)
+{
+	return bdi_congested(bdi, 1 << BDI_async_congested);
+}
+
+static inline int bdi_rw_congested(struct backing_dev_info *bdi)
+{
+	return bdi_congested(bdi, (1 << BDI_sync_congested) |
+				  (1 << BDI_async_congested));
+}
+
+enum {
+	BLK_RW_ASYNC	= 0,
+	BLK_RW_SYNC	= 1,
+};
+
+void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
+void set_bdi_congested(struct backing_dev_info *bdi, int sync);
+long congestion_wait(int sync, long timeout);
+long wait_iff_congested(struct zone *zone, int sync, long timeout);
+int pdflush_proc_obsolete(struct ctl_table *table, int write,
+		void __user *buffer, size_t *lenp, loff_t *ppos);
+
+static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi)
+{
+	return bdi->capabilities & BDI_CAP_STABLE_WRITES;
+}
+
+static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi)
+{
+	return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK);
+}
+
+static inline bool bdi_cap_account_dirty(struct backing_dev_info *bdi)
+{
+	return !(bdi->capabilities & BDI_CAP_NO_ACCT_DIRTY);
+}
+
+static inline bool bdi_cap_account_writeback(struct backing_dev_info *bdi)
+{
+	/* Paranoia: BDI_CAP_NO_WRITEBACK implies BDI_CAP_NO_ACCT_WB */
+	return !(bdi->capabilities & (BDI_CAP_NO_ACCT_WB |
+				      BDI_CAP_NO_WRITEBACK));
+}
+
+static inline bool mapping_cap_writeback_dirty(struct address_space *mapping)
+{
+	return bdi_cap_writeback_dirty(inode_to_bdi(mapping->host));
+}
+
+static inline bool mapping_cap_account_dirty(struct address_space *mapping)
+{
+	return bdi_cap_account_dirty(inode_to_bdi(mapping->host));
+}
+
+static inline int bdi_sched_wait(void *word)
+{
+	schedule();
+	return 0;
+}
+
+#endif		/* _LINUX_BACKING_DEV_H */