// SPDX-License-Identifier: GPL-2.0
/*
* 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 sector_t bio_discard_limit(struct block_device *bdev, sector_t sector)
{
unsigned int discard_granularity = bdev_discard_granularity(bdev);
sector_t granularity_aligned_sector;
if (bdev_is_partition(bdev))
sector += bdev->bd_start_sect;
granularity_aligned_sector =
round_up(sector, discard_granularity >> SECTOR_SHIFT);
/*
* Make sure subsequent bios start aligned to the discard granularity if
* it needs to be split.
*/
if (granularity_aligned_sector != sector)
return granularity_aligned_sector - sector;
/*
* Align the bio size to the discard granularity to make splitting the bio
* at discard granularity boundaries easier in the driver if needed.
*/
return round_down(UINT_MAX, discard_granularity) >> SECTOR_SHIFT;
}
struct bio *blk_alloc_discard_bio(struct block_device *bdev,
sector_t *sector, sector_t *nr_sects, gfp_t gfp_mask)
{
sector_t bio_sects = min(*nr_sects, bio_discard_limit(bdev, *sector));
struct bio *bio;
if (!bio_sects)
return NULL;
bio = bio_alloc(bdev, 0, REQ_OP_DISCARD, gfp_mask);
if (!bio)
return NULL;
bio->bi_iter.bi_sector = *sector;
bio->bi_iter.bi_size = bio_sects << SECTOR_SHIFT;
*sector += bio_sects;
*nr_sects -= bio_sects;
/*
* We can loop for a long time in here if someone does full device
* discards (like mkfs). Be nice and allow us to schedule out to avoid
* softlocking if preempt is disabled.
*/
cond_resched();
return bio;
}
int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct bio **biop)
{
struct bio *bio;
while ((bio = blk_alloc_discard_bio(bdev, §or, &nr_sects,
gfp_mask)))
*biop = bio_chain_and_submit(*biop, bio);
return 0;
}
EXPORT_SYMBOL(__blkdev_issue_discard);
/**
* 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)
*
* 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)
{
struct bio *bio = NULL;
struct blk_plug plug;
int ret;
blk_start_plug(&plug);
ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, &bio);
if (!ret && bio) {
ret = submit_bio_wait(bio);
if (ret == -EOPNOTSUPP)
ret = 0;
bio_put(bio);
}
blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL(blkdev_issue_discard);
static sector_t bio_write_zeroes_limit(struct block_device *bdev)
{
sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
return min(bdev_write_zeroes_sectors(bdev),
(UINT_MAX >> SECTOR_SHIFT) & ~bs_mask);
}
/*
* There is no reliable way for the SCSI subsystem to determine whether a
* device supports a WRITE SAME operation without actually performing a write
* to media. As a result, write_zeroes is enabled by default and will be
* disabled if a zeroing operation subsequently fails. This means that this
* queue limit is likely to change at runtime.
*/
static void __blkdev_issue_write_zeroes(struct block_device *bdev,
sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
struct bio **biop, unsigned flags, sector_t limit)
{
while (nr_sects) {
unsigned int len = min(nr_sects, limit);
struct bio *bio;
if ((flags & BLKDEV_ZERO_KILLABLE) &&
fatal_signal_pending(current))
break;
bio = bio_alloc(bdev, 0, REQ_OP_WRITE_ZEROES, gfp_mask);
bio->bi_iter.bi_sector = sector;
if (flags & BLKDEV_ZERO_NOUNMAP)
bio->bi_opf |= REQ_NOUNMAP;
bio->bi_iter.bi_size = len << SECTOR_SHIFT;
*biop = bio_chain_and_submit(*biop, bio);
nr_sects -= len;
sector += len;
cond_resched();
}
}
static int blkdev_issue_write_zeroes(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp, unsigned flags)
{
sector_t limit = bio_write_zeroes_limit(bdev);
struct bio *bio = NULL;
struct blk_plug plug;
int ret = 0;
blk_start_plug(&plug);
__blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp, &bio,
flags, limit);
if (bio) {
if ((flags & BLKDEV_ZERO_KILLABLE) &&
fatal_signal_pending(current)) {
bio_await_chain(bio);
blk_finish_plug(&plug);
return -EINTR;
}
ret = submit_bio_wait(bio);
bio_put(bio);
}
blk_finish_plug(&plug);
/*
* For some devices there is no non-destructive way to verify whether
* WRITE ZEROES is actually supported. These will clear the capability
* on an I/O error, in which case we'll turn any error into
* "not supported" here.
*/
if (ret && !bdev_write_zeroes_sectors(bdev))
return -EOPNOTSUPP;
return ret;
}
/*
* Convert a number of 512B sectors to a number of pages.
* The result is limited to a number of pages that can fit into a BIO.
* Also make sure that the result is always at least 1 (page) for the cases
* where nr_sects is lower than the number of sectors in a page.
*/
static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
{
sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
return min(pages, (sector_t)BIO_MAX_VECS);
}
static void __blkdev_issue_zero_pages(struct block_device *bdev,
sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
struct bio **biop, unsigned int flags)
{
while (nr_sects) {
unsigned int nr_vecs = __blkdev_sectors_to_bio_pages(nr_sects);
struct bio *bio;
bio = bio_alloc(bdev, nr_vecs, REQ_OP_WRITE, gfp_mask);
bio->bi_iter.bi_sector = sector;
if ((flags & BLKDEV_ZERO_KILLABLE) &&
fatal_signal_pending(current))
break;
do {
unsigned int len, added;
len = min_t(sector_t,
PAGE_SIZE, nr_sects << SECTOR_SHIFT);
added = bio_add_page(bio, ZERO_PAGE(0), len, 0);
if (added < len)
break;
nr_sects -= added >> SECTOR_SHIFT;
sector += added >> SECTOR_SHIFT;
} while (nr_sects);
*biop = bio_chain_and_submit(*biop, bio);
cond_resched();
}
}
static int blkdev_issue_zero_pages(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp, unsigned flags)
{
struct bio *bio = NULL;
struct blk_plug plug;
int ret = 0;
if (flags & BLKDEV_ZERO_NOFALLBACK)
return -EOPNOTSUPP;
blk_start_plug(&plug);
__blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp, &bio, flags);
if (bio) {
if ((flags & BLKDEV_ZERO_KILLABLE) &&
fatal_signal_pending(current)) {
bio_await_chain(bio);
blk_finish_plug(&plug);
return -EINTR;
}
ret = submit_bio_wait(bio);
bio_put(bio);
}
blk_finish_plug(&plug);
return ret;
}
/**
* __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)
* @biop: pointer to anchor bio
* @flags: controls detailed behavior
*
* Description:
* Zero-fill a block range, either using hardware offload or by explicitly
* writing zeroes to the device.
*
* If a device is using logical block provisioning, the underlying space will
* not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
*
* If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
* -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
*/
int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
unsigned flags)
{
sector_t limit = bio_write_zeroes_limit(bdev);
if (bdev_read_only(bdev))
return -EPERM;
if (limit) {
__blkdev_issue_write_zeroes(bdev, sector, nr_sects,
gfp_mask, biop, flags, limit);
} else {
if (flags & BLKDEV_ZERO_NOFALLBACK)
return -EOPNOTSUPP;
__blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
biop, flags);
}
return 0;
}
EXPORT_SYMBOL(__blkdev_issue_zeroout);
/**
* blkdev_issue_zeroout - zero-fill a block range
* @bdev: blockdev to write
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
* @flags: controls detailed behavior
*
* Description:
* Zero-fill a block range, either using hardware offload or by explicitly
* writing zeroes to the device. See __blkdev_issue_zeroout() for the
* valid values for %flags.
*/
int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
{
int ret;
if ((sector | nr_sects) & ((bdev_logical_block_size(bdev) >> 9) - 1))
return -EINVAL;
if (bdev_read_only(bdev))
return -EPERM;
if (bdev_write_zeroes_sectors(bdev)) {
ret = blkdev_issue_write_zeroes(bdev, sector, nr_sects,
gfp_mask, flags);
if (ret != -EOPNOTSUPP)
return ret;
}
return blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask, flags);
}
EXPORT_SYMBOL(blkdev_issue_zeroout);
int blkdev_issue_secure_erase(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp)
{
sector_t bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
unsigned int max_sectors = bdev_max_secure_erase_sectors(bdev);
struct bio *bio = NULL;
struct blk_plug plug;
int ret = 0;
/* make sure that "len << SECTOR_SHIFT" doesn't overflow */
if (max_sectors > UINT_MAX >> SECTOR_SHIFT)
max_sectors = UINT_MAX >> SECTOR_SHIFT;
max_sectors &= ~bs_mask;
if (max_sectors == 0)
return -EOPNOTSUPP;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
if (bdev_read_only(bdev))
return -EPERM;
blk_start_plug(&plug);
while (nr_sects) {
unsigned int len = min_t(sector_t, nr_sects, max_sectors);
bio = blk_next_bio(bio, bdev, 0, REQ_OP_SECURE_ERASE, gfp);
bio->bi_iter.bi_sector = sector;
bio->bi_iter.bi_size = len << SECTOR_SHIFT;
sector += len;
nr_sects -= len;
cond_resched();
}
if (bio) {
ret = submit_bio_wait(bio);
bio_put(bio);
}
blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL(blkdev_issue_secure_erase);
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