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/*
* 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);
struct bio_batch
{
atomic_t done;
unsigned long flags;
struct completion *wait;
bio_end_io_t *end_io;
};
static void bio_batch_end_io(struct bio *bio, int err)
{
struct bio_batch *bb = bio->bi_private;
if (err) {
if (err == -EOPNOTSUPP)
set_bit(BIO_EOPNOTSUPP, &bb->flags);
else
clear_bit(BIO_UPTODATE, &bb->flags);
}
if (bb) {
if (bb->end_io)
bb->end_io(bio, err);
atomic_inc(&bb->done);
complete(bb->wait);
}
bio_put(bio);
}
/**
* blkdev_issue_zeroout generate number of zero filed write bios
* @bdev: blockdev to issue
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
* @flags: BLKDEV_IFL_* flags to control behaviour
*
* Description:
* Generate and issue number of bios with zerofiled pages.
* Send barrier at the beginning and at the end if requested. This guarantie
* correct request ordering. Empty barrier allow us to avoid post queue flush.
*/
int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
{
int ret = 0;
struct bio *bio;
struct bio_batch bb;
unsigned int sz, issued = 0;
DECLARE_COMPLETION_ONSTACK(wait);
atomic_set(&bb.done, 0);
bb.flags = 1 << BIO_UPTODATE;
bb.wait = &wait;
bb.end_io = NULL;
if (flags & BLKDEV_IFL_BARRIER) {
/* issue async barrier before the data */
ret = blkdev_issue_flush(bdev, gfp_mask, NULL, 0);
if (ret)
return ret;
}
submit:
while (nr_sects != 0) {
bio = bio_alloc(gfp_mask,
min(nr_sects, (sector_t)BIO_MAX_PAGES));
if (!bio)
break;
bio->bi_sector = sector;
bio->bi_bdev = bdev;
bio->bi_end_io = bio_batch_end_io;
if (flags & BLKDEV_IFL_WAIT)
bio->bi_private = &bb;
while(nr_sects != 0) {
sz = min(PAGE_SIZE >> 9 , nr_sects);
if (sz == 0)
/* bio has maximum size possible */
break;
ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
nr_sects -= ret >> 9;
sector += ret >> 9;
if (ret < (sz << 9))
break;
}
issued++;
submit_bio(WRITE, bio);
}
/*
* When all data bios are in flight. Send final barrier if requeted.
*/
if (nr_sects == 0 && flags & BLKDEV_IFL_BARRIER)
ret = blkdev_issue_flush(bdev, gfp_mask, NULL,
flags & BLKDEV_IFL_WAIT);
if (flags & BLKDEV_IFL_WAIT)
/* Wait for bios in-flight */
while ( issued != atomic_read(&bb.done))
wait_for_completion(&wait);
if (!test_bit(BIO_UPTODATE, &bb.flags))
/* One of bios in the batch was completed with error.*/
ret = -EIO;
if (ret)
goto out;
if (test_bit(BIO_EOPNOTSUPP, &bb.flags)) {
ret = -EOPNOTSUPP;
goto out;
}
if (nr_sects != 0)
goto submit;
out:
return ret;
}
EXPORT_SYMBOL(blkdev_issue_zeroout);
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