| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * 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/kernel.h> |
| #include <linux/fs.h> |
| #include <linux/sched.h> |
| #include <linux/blkdev.h> |
| #include <linux/device.h> |
| #include <linux/writeback.h> |
| #include <linux/blk-cgroup.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_wakeup_delayed(struct bdi_writeback *wb); |
| |
| 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; |
| extern struct workqueue_struct *bdi_async_bio_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 __add_wb_stat(struct bdi_writeback *wb, |
| enum wb_stat_item item, s64 amount) |
| { |
| percpu_counter_add_batch(&wb->stat[item], amount, WB_STAT_BATCH); |
| } |
| |
| static inline void inc_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
| { |
| __add_wb_stat(wb, item, 1); |
| } |
| |
| static inline void dec_wb_stat(struct bdi_writeback *wb, enum wb_stat_item item) |
| { |
| __add_wb_stat(wb, item, -1); |
| } |
| |
| 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]); |
| } |
| |
| extern void wb_writeout_inc(struct bdi_writeback *wb); |
| |
| /* |
| * 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 |
| } |
| |
| 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 |
| * |
| * BDI_CAP_WRITEBACK: Supports dirty page writeback, and dirty pages |
| * should contribute to accounting |
| * BDI_CAP_WRITEBACK_ACCT: Automatically account writeback pages |
| * BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold |
| */ |
| #define BDI_CAP_WRITEBACK (1 << 0) |
| #define BDI_CAP_WRITEBACK_ACCT (1 << 1) |
| #define BDI_CAP_STRICTLIMIT (1 << 2) |
| |
| extern struct backing_dev_info noop_backing_dev_info; |
| |
| /** |
| * 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); |
| } |
| |
| static inline struct backing_dev_info *inode_to_bdi(struct inode *inode) |
| { |
| struct super_block *sb; |
| |
| if (!inode) |
| return &noop_backing_dev_info; |
| |
| sb = inode->i_sb; |
| #ifdef CONFIG_BLOCK |
| if (sb_is_blkdev_sb(sb)) |
| return I_BDEV(inode)->bd_bdi; |
| #endif |
| return sb->s_bdi; |
| } |
| |
| static inline int wb_congested(struct bdi_writeback *wb, int cong_bits) |
| { |
| return wb->congested & cong_bits; |
| } |
| |
| long congestion_wait(int sync, long timeout); |
| long wait_iff_congested(int sync, long timeout); |
| |
| static inline bool mapping_can_writeback(struct address_space *mapping) |
| { |
| return inode_to_bdi(mapping->host)->capabilities & BDI_CAP_WRITEBACK; |
| } |
| |
| static inline int bdi_sched_wait(void *word) |
| { |
| schedule(); |
| return 0; |
| } |
| |
| #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 blkcg *blkcg); |
| int inode_congested(struct inode *inode, int cong_bits); |
| |
| /** |
| * 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_is_valid - test whether an inode has a wb associated |
| * @inode: inode of interest |
| * |
| * Returns %true if @inode has a wb associated. May be called without any |
| * locking. |
| */ |
| static inline bool inode_to_wb_is_valid(struct inode *inode) |
| { |
| return inode->i_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 && |
| (!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; |
| } |
| |
| /** |
| * 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 store_release in inode_switch_wbs_work_fn() and |
| * ensures that we see the new wb if we see cleared I_WB_SWITCH. |
| */ |
| cookie->locked = smp_load_acquire(&inode->i_state) & I_WB_SWITCH; |
| |
| 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 bool inode_to_wb_is_valid(struct inode *inode) |
| { |
| return true; |
| } |
| |
| static inline struct bdi_writeback *inode_to_wb(struct inode *inode) |
| { |
| return &inode_to_bdi(inode)->wb; |
| } |
| |
| 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 blkcg *blkcg) |
| { |
| } |
| |
| static inline int inode_congested(struct inode *inode, int cong_bits) |
| { |
| return wb_congested(&inode_to_bdi(inode)->wb, cong_bits); |
| } |
| |
| #endif /* CONFIG_CGROUP_WRITEBACK */ |
| |
| static inline int inode_read_congested(struct inode *inode) |
| { |
| return inode_congested(inode, 1 << WB_sync_congested); |
| } |
| |
| static inline int inode_write_congested(struct inode *inode) |
| { |
| return inode_congested(inode, 1 << WB_async_congested); |
| } |
| |
| static inline int inode_rw_congested(struct inode *inode) |
| { |
| return inode_congested(inode, (1 << WB_sync_congested) | |
| (1 << WB_async_congested)); |
| } |
| |
| static inline int bdi_congested(struct backing_dev_info *bdi, int cong_bits) |
| { |
| return wb_congested(&bdi->wb, cong_bits); |
| } |
| |
| static inline int bdi_read_congested(struct backing_dev_info *bdi) |
| { |
| return bdi_congested(bdi, 1 << WB_sync_congested); |
| } |
| |
| static inline int bdi_write_congested(struct backing_dev_info *bdi) |
| { |
| return bdi_congested(bdi, 1 << WB_async_congested); |
| } |
| |
| static inline int bdi_rw_congested(struct backing_dev_info *bdi) |
| { |
| return bdi_congested(bdi, (1 << WB_sync_congested) | |
| (1 << WB_async_congested)); |
| } |
| |
| const char *bdi_dev_name(struct backing_dev_info *bdi); |
| |
| #endif /* _LINUX_BACKING_DEV_H */ |