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Commit c3c53206 authored by Jens Axboe's avatar Jens Axboe
Browse files

bdi: add helper function for doing init and register of a bdi for a file system 



Pretty trivial helper, just sets up the bdi and registers it. An atomic
sequence count is used to ensure that the registered sysfs names are
unique.

Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent a534dbe9

include/linux/backing-dev.h

+1 −0
Original line number Diff line number Diff line
@@ -101,6 +101,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent, 
		const char *fmt, ...);

int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev);

void bdi_unregister(struct backing_dev_info *bdi);

int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int);

void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb,

				long nr_pages);

int bdi_writeback_task(struct bdi_writeback *wb);

mm/backing-dev.c

+29 −0
Original line number Diff line number Diff line
@@ -11,6 +11,8 @@ 
#include <linux/writeback.h>

#include <linux/device.h>



static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);



void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)

{

}
@@ -715,6 +717,33 @@ void bdi_destroy(struct backing_dev_info *bdi) 
}

EXPORT_SYMBOL(bdi_destroy);



/*

 * For use from filesystems to quickly init and register a bdi associated

 * with dirty writeback

 */

int bdi_setup_and_register(struct backing_dev_info *bdi, char *name,

			   unsigned int cap)

{

	char tmp[32];

	int err;



	bdi->name = name;

	bdi->capabilities = cap;

	err = bdi_init(bdi);

	if (err)

		return err;



	sprintf(tmp, "%.28s%s", name, "-%d");

	err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq));

	if (err) {

		bdi_destroy(bdi);

		return err;

	}



	return 0;

}

EXPORT_SYMBOL(bdi_setup_and_register);



static wait_queue_head_t congestion_wqh[2] = {

		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),

		__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])