Subversion Repositories test_project

#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);