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- #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);
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