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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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C
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#ifndef _LINUX_BACKING_DEV_H#define _LINUX_BACKING_DEV_H
#include <linux/kernel.h>#include <linux/fs.h>#include <linux/sched.h>#include <linux/device.h>#include <linux/writeback.h>#include <linux/backing-dev-defs.h>#include <linux/slab.h>
static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi){ kref_get(&bdi->refcnt); return bdi;}
struct backing_dev_info *bdi_get_by_id(u64 id);void bdi_put(struct backing_dev_info *bdi);
__printf(2, 3)int bdi_register(struct backing_dev_info *bdi, const char *fmt, ...);__printf(2, 0)int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args);void bdi_set_owner(struct backing_dev_info *bdi, struct device *owner);void bdi_unregister(struct backing_dev_info *bdi);
struct backing_dev_info *bdi_alloc(int node_id);
void wb_start_background_writeback(struct bdi_writeback *wb);void wb_workfn(struct work_struct *work);
void wb_wait_for_completion(struct wb_completion *done);
extern spinlock_t bdi_lock;extern struct list_head bdi_list;
extern struct workqueue_struct *bdi_wq;
static inline bool wb_has_dirty_io(struct bdi_writeback *wb){ return test_bit(WB_has_dirty_io, &wb->state);}
static inline bool bdi_has_dirty_io(struct backing_dev_info *bdi){ /* * @bdi->tot_write_bandwidth is guaranteed to be > 0 if there are * any dirty wbs. See wb_update_write_bandwidth(). */ return atomic_long_read(&bdi->tot_write_bandwidth);}
static inline void wb_stat_mod(struct bdi_writeback *wb, enum wb_stat_item item, s64 amount){ percpu_counter_add_batch(&wb->stat[item], amount, WB_STAT_BATCH);}
static inline s64 wb_stat(struct bdi_writeback *wb, enum wb_stat_item item){ return percpu_counter_read_positive(&wb->stat[item]);}
static inline s64 wb_stat_sum(struct bdi_writeback *wb, enum wb_stat_item item){ return percpu_counter_sum_positive(&wb->stat[item]);}
/* * maximal error of a stat counter. */static inline unsigned long wb_stat_error(void){#ifdef CONFIG_SMP return nr_cpu_ids * WB_STAT_BATCH;#else return 1;#endif}
/* BDI ratio is expressed as part per 1000000 for finer granularity. */#define BDI_RATIO_SCALE 10000
u64 bdi_get_min_bytes(struct backing_dev_info *bdi);u64 bdi_get_max_bytes(struct backing_dev_info *bdi);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);int bdi_set_min_ratio_no_scale(struct backing_dev_info *bdi, unsigned int min_ratio);int bdi_set_max_ratio_no_scale(struct backing_dev_info *bdi, unsigned int max_ratio);int bdi_set_min_bytes(struct backing_dev_info *bdi, u64 min_bytes);int bdi_set_max_bytes(struct backing_dev_info *bdi, u64 max_bytes);int bdi_set_strict_limit(struct backing_dev_info *bdi, unsigned int strict_limit);
/* * Flags in backing_dev_info::capability * * BDI_CAP_WRITEBACK: Supports dirty page writeback, and dirty pages * should contribute to accounting * BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold */#define BDI_CAP_WRITEBACK (1 << 0)#define BDI_CAP_STRICTLIMIT (1 << 1)
extern struct backing_dev_info noop_backing_dev_info;
int bdi_init(struct backing_dev_info *bdi);
/** * writeback_in_progress - determine whether there is writeback in progress * @wb: bdi_writeback of interest * * Determine whether there is writeback waiting to be handled against a * bdi_writeback. */static inline bool writeback_in_progress(struct bdi_writeback *wb){ return test_bit(WB_writeback_running, &wb->state);}
struct backing_dev_info *inode_to_bdi(struct inode *inode);
static inline bool mapping_can_writeback(struct address_space *mapping){ return inode_to_bdi(mapping->host)->capabilities & BDI_CAP_WRITEBACK;}
/* Must not be used by file systems that support cgroup writeback */static inline int bdi_wb_dirty_exceeded(struct backing_dev_info *bdi){ return bdi->wb.dirty_exceeded;}
/* Must not be used by file systems that support cgroup writeback */static inline void bdi_wb_stat_mod(struct inode *inode, enum wb_stat_item item, s64 amount){ wb_stat_mod(&inode_to_bdi(inode)->wb, item, amount);}
#ifdef CONFIG_CGROUP_WRITEBACK
struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi, struct cgroup_subsys_state *memcg_css);struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi, struct cgroup_subsys_state *memcg_css, gfp_t gfp);void wb_memcg_offline(struct mem_cgroup *memcg);void wb_blkcg_offline(struct cgroup_subsys_state *css);
/** * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode * @inode: inode of interest * * Cgroup writeback requires support from the filesystem. Also, both memcg and * iocg have to be on the default hierarchy. Test whether all conditions are * met. * * Note that the test result may change dynamically on the same inode * depending on how memcg and iocg are configured. */static inline bool inode_cgwb_enabled(struct inode *inode){ struct backing_dev_info *bdi = inode_to_bdi(inode);
return cgroup_subsys_on_dfl(memory_cgrp_subsys) && cgroup_subsys_on_dfl(io_cgrp_subsys) && (bdi->capabilities & BDI_CAP_WRITEBACK) && (inode->i_sb->s_iflags & SB_I_CGROUPWB);}
/** * wb_find_current - find wb for %current on a bdi * @bdi: bdi of interest * * Find the wb of @bdi which matches both the memcg and blkcg of %current. * Must be called under rcu_read_lock() which protects the returend wb. * NULL if not found. */static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi){ struct cgroup_subsys_state *memcg_css; struct bdi_writeback *wb;
memcg_css = task_css(current, memory_cgrp_id); if (!memcg_css->parent) return &bdi->wb;
wb = radix_tree_lookup(&bdi->cgwb_tree, memcg_css->id);
/* * %current's blkcg equals the effective blkcg of its memcg. No * need to use the relatively expensive cgroup_get_e_css(). */ if (likely(wb && wb->blkcg_css == task_css(current, io_cgrp_id))) return wb; return NULL;}
/** * wb_get_create_current - get or create wb for %current on a bdi * @bdi: bdi of interest * @gfp: allocation mask * * Equivalent to wb_get_create() on %current's memcg. This function is * called from a relatively hot path and optimizes the common cases using * wb_find_current(). */static inline struct bdi_writeback *wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp){ struct bdi_writeback *wb;
rcu_read_lock(); wb = wb_find_current(bdi); if (wb && unlikely(!wb_tryget(wb))) wb = NULL; rcu_read_unlock();
if (unlikely(!wb)) { struct cgroup_subsys_state *memcg_css;
memcg_css = task_get_css(current, memory_cgrp_id); wb = wb_get_create(bdi, memcg_css, gfp); css_put(memcg_css); } return wb;}
/** * inode_to_wb - determine the wb of an inode * @inode: inode of interest * * Returns the wb @inode is currently associated with. The caller must be * holding either @inode->i_lock, the i_pages lock, or the * associated wb's list_lock. */static inline struct bdi_writeback *inode_to_wb(const struct inode *inode){#ifdef CONFIG_LOCKDEP WARN_ON_ONCE(debug_locks && (inode->i_sb->s_iflags & SB_I_CGROUPWB) && (!lockdep_is_held(&inode->i_lock) && !lockdep_is_held(&inode->i_mapping->i_pages.xa_lock) && !lockdep_is_held(&inode->i_wb->list_lock)));#endif return inode->i_wb;}
static inline struct bdi_writeback *inode_to_wb_wbc( struct inode *inode, struct writeback_control *wbc){ /* * If wbc does not have inode attached, it means cgroup writeback was * disabled when wbc started. Just use the default wb in that case. */ return wbc->wb ? wbc->wb : &inode_to_bdi(inode)->wb;}
/** * unlocked_inode_to_wb_begin - begin unlocked inode wb access transaction * @inode: target inode * @cookie: output param, to be passed to the end function * * The caller wants to access the wb associated with @inode but isn't * holding inode->i_lock, the i_pages lock or wb->list_lock. This * function determines the wb associated with @inode and ensures that the * association doesn't change until the transaction is finished with * unlocked_inode_to_wb_end(). * * The caller must call unlocked_inode_to_wb_end() with *@cookie afterwards and * can't sleep during the transaction. IRQs may or may not be disabled on * return. */static inline struct bdi_writeback *unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie){ rcu_read_lock();
/* * Paired with a release fence in inode_do_switch_wbs() and * ensures that we see the new wb if we see cleared I_WB_SWITCH. */ cookie->locked = inode_state_read_once(inode) & I_WB_SWITCH; smp_rmb();
if (unlikely(cookie->locked)) xa_lock_irqsave(&inode->i_mapping->i_pages, cookie->flags);
/* * Protected by either !I_WB_SWITCH + rcu_read_lock() or the i_pages * lock. inode_to_wb() will bark. Deref directly. */ return inode->i_wb;}
/** * unlocked_inode_to_wb_end - end inode wb access transaction * @inode: target inode * @cookie: @cookie from unlocked_inode_to_wb_begin() */static inline void unlocked_inode_to_wb_end(struct inode *inode, struct wb_lock_cookie *cookie){ if (unlikely(cookie->locked)) xa_unlock_irqrestore(&inode->i_mapping->i_pages, cookie->flags);
rcu_read_unlock();}
#else /* CONFIG_CGROUP_WRITEBACK */
static inline bool inode_cgwb_enabled(struct inode *inode){ return false;}
static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi){ return &bdi->wb;}
static inline struct bdi_writeback *wb_get_create_current(struct backing_dev_info *bdi, gfp_t gfp){ return &bdi->wb;}
static inline struct bdi_writeback *inode_to_wb(struct inode *inode){ return &inode_to_bdi(inode)->wb;}
static inline struct bdi_writeback *inode_to_wb_wbc( struct inode *inode, struct writeback_control *wbc){ return inode_to_wb(inode);}
static inline struct bdi_writeback *unlocked_inode_to_wb_begin(struct inode *inode, struct wb_lock_cookie *cookie){ return inode_to_wb(inode);}
static inline void unlocked_inode_to_wb_end(struct inode *inode, struct wb_lock_cookie *cookie){}
static inline void wb_memcg_offline(struct mem_cgroup *memcg){}
static inline void wb_blkcg_offline(struct cgroup_subsys_state *css){}
#endif /* CONFIG_CGROUP_WRITEBACK */
const char *bdi_dev_name(struct backing_dev_info *bdi);
#endif /* _LINUX_BACKING_DEV_H */