115 lines
2.7 KiB
C
115 lines
2.7 KiB
C
|
/*
|
||
|
|
* Functions related to generic helpers functions
|
||
|
|
*/
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
#include <linux/module.h>
|
||
|
|
#include <linux/bio.h>
|
||
|
|
#include <linux/blkdev.h>
|
||
|
|
#include <linux/scatterlist.h>
|
||
|
|
|
||
|
|
#include "blk.h"
|
||
|
|
|
||
|
|
static void blkdev_discard_end_io(struct bio *bio, int err)
|
||
|
|
{
|
||
|
|
if (err) {
|
||
|
|
if (err == -EOPNOTSUPP)
|
||
|
|
set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
|
||
|
|
clear_bit(BIO_UPTODATE, &bio->bi_flags);
|
||
|
|
}
|
||
|
|
|
||
|
|
if (bio->bi_private)
|
||
|
|
complete(bio->bi_private);
|
||
|
|
__free_page(bio_page(bio));
|
||
|
|
|
||
|
|
bio_put(bio);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* blkdev_issue_discard - queue a discard
|
||
|
|
* @bdev: blockdev to issue discard for
|
||
|
|
* @sector: start sector
|
||
|
|
* @nr_sects: number of sectors to discard
|
||
|
|
* @gfp_mask: memory allocation flags (for bio_alloc)
|
||
|
|
* @flags: BLKDEV_IFL_* flags to control behaviour
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* Issue a discard request for the sectors in question.
|
||
|
|
*/
|
||
|
|
int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
|
||
|
|
sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
|
||
|
|
{
|
||
|
|
DECLARE_COMPLETION_ONSTACK(wait);
|
||
|
|
struct request_queue *q = bdev_get_queue(bdev);
|
||
|
|
int type = flags & BLKDEV_IFL_BARRIER ?
|
||
|
|
DISCARD_BARRIER : DISCARD_NOBARRIER;
|
||
|
|
struct bio *bio;
|
||
|
|
struct page *page;
|
||
|
|
int ret = 0;
|
||
|
|
|
||
|
|
if (!q)
|
||
|
|
return -ENXIO;
|
||
|
|
|
||
|
|
if (!blk_queue_discard(q))
|
||
|
|
return -EOPNOTSUPP;
|
||
|
|
|
||
|
|
while (nr_sects && !ret) {
|
||
|
|
unsigned int sector_size = q->limits.logical_block_size;
|
||
|
|
unsigned int max_discard_sectors =
|
||
|
|
min(q->limits.max_discard_sectors, UINT_MAX >> 9);
|
||
|
|
|
||
|
|
bio = bio_alloc(gfp_mask, 1);
|
||
|
|
if (!bio)
|
||
|
|
goto out;
|
||
|
|
bio->bi_sector = sector;
|
||
|
|
bio->bi_end_io = blkdev_discard_end_io;
|
||
|
|
bio->bi_bdev = bdev;
|
||
|
|
if (flags & BLKDEV_IFL_WAIT)
|
||
|
|
bio->bi_private = &wait;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Add a zeroed one-sector payload as that's what
|
||
|
|
* our current implementations need. If we'll ever need
|
||
|
|
* more the interface will need revisiting.
|
||
|
|
*/
|
||
|
|
page = alloc_page(gfp_mask | __GFP_ZERO);
|
||
|
|
if (!page)
|
||
|
|
goto out_free_bio;
|
||
|
|
if (bio_add_pc_page(q, bio, page, sector_size, 0) < sector_size)
|
||
|
|
goto out_free_page;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* And override the bio size - the way discard works we
|
||
|
|
* touch many more blocks on disk than the actual payload
|
||
|
|
* length.
|
||
|
|
*/
|
||
|
|
if (nr_sects > max_discard_sectors) {
|
||
|
|
bio->bi_size = max_discard_sectors << 9;
|
||
|
|
nr_sects -= max_discard_sectors;
|
||
|
|
sector += max_discard_sectors;
|
||
|
|
} else {
|
||
|
|
bio->bi_size = nr_sects << 9;
|
||
|
|
nr_sects = 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
bio_get(bio);
|
||
|
|
submit_bio(type, bio);
|
||
|
|
|
||
|
|
if (flags & BLKDEV_IFL_WAIT)
|
||
|
|
wait_for_completion(&wait);
|
||
|
|
|
||
|
|
if (bio_flagged(bio, BIO_EOPNOTSUPP))
|
||
|
|
ret = -EOPNOTSUPP;
|
||
|
|
else if (!bio_flagged(bio, BIO_UPTODATE))
|
||
|
|
ret = -EIO;
|
||
|
|
bio_put(bio);
|
||
|
|
}
|
||
|
|
return ret;
|
||
|
|
out_free_page:
|
||
|
|
__free_page(page);
|
||
|
|
out_free_bio:
|
||
|
|
bio_put(bio);
|
||
|
|
out:
|
||
|
|
return -ENOMEM;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(blkdev_issue_discard);
|