#include <linux/wait.h> #include <linux/backing-dev.h> #include <linux/fs.h> #include <linux/sched.h> #include <linux/module.h> 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); long congestion_wait_interruptible(int rw, long timeout) { long ret; DEFINE_WAIT(wait); wait_queue_head_t *wqh = &congestion_wqh[rw]; prepare_to_wait(wqh, &wait, TASK_INTERRUPTIBLE); if (signal_pending(current)) ret = -ERESTARTSYS; else ret = io_schedule_timeout(timeout); finish_wait(wqh, &wait); return ret; } EXPORT_SYMBOL(congestion_wait_interruptible); /** * congestion_end - wake up sleepers on a congested backing_dev_info * @rw: READ or WRITE */ void congestion_end(int rw) { wait_queue_head_t *wqh = &congestion_wqh[rw]; if (waitqueue_active(wqh)) wake_up(wqh); } EXPORT_SYMBOL(congestion_end);