#include <linux/wait.h> #include <linux/backing-dev.h> #include <linux/fs.h> #include <linux/sched.h> #include <linux/module.h> int bdi_init(struct backing_dev_info *bdi) { int i; int err; for (i = 0; i < NR_BDI_STAT_ITEMS; i++) { err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0); if (err) goto err; } bdi->dirty_exceeded = 0; err = prop_local_init_percpu(&bdi->completions); if (err) { err: while (i--) percpu_counter_destroy(&bdi->bdi_stat[i]); } return err; } EXPORT_SYMBOL(bdi_init); void bdi_destroy(struct backing_dev_info *bdi) { int i; for (i = 0; i < NR_BDI_STAT_ITEMS; i++) percpu_counter_destroy(&bdi->bdi_stat[i]); prop_local_destroy_percpu(&bdi->completions); } EXPORT_SYMBOL(bdi_destroy); static wait_queue_head_t congestion_wqh[2] = { __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) }; void clear_bdi_congested(struct backing_dev_info *bdi, int rw) { enum bdi_state bit; wait_queue_head_t *wqh = &congestion_wqh[rw]; bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; clear_bit(bit, &bdi->state); smp_mb__after_clear_bit(); if (waitqueue_active(wqh)) wake_up(wqh); } EXPORT_SYMBOL(clear_bdi_congested); void set_bdi_congested(struct backing_dev_info *bdi, int rw) { enum bdi_state bit; bit = (rw == WRITE) ? BDI_write_congested : BDI_read_congested; set_bit(bit, &bdi->state); } EXPORT_SYMBOL(set_bdi_congested); /** * congestion_wait - wait for a backing_dev to become uncongested * @rw: READ or WRITE * @timeout: timeout in jiffies * * Waits for up to @timeout jiffies for a backing_dev (any backing_dev) to exit * write congestion. If no backing_devs are congested then just wait for the * next write to be completed. */ long congestion_wait(int rw, long timeout) { long ret; DEFINE_WAIT(wait); wait_queue_head_t *wqh = &congestion_wqh[rw]; prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE); ret = io_schedule_timeout(timeout); finish_wait(wqh, &wait); return ret; } EXPORT_SYMBOL(congestion_wait);