// 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 struct bio *next_bio(struct bio *bio, unsigned int nr_pages,
gfp_t gfp)
{
struct bio *new = bio_alloc(gfp, nr_pages);
if (bio) {
bio_chain(bio, new);
submit_bio(bio);
}
return new;
}
int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, int flags,
struct bio **biop)
{
struct request_queue *q = bdev_get_queue(bdev);
struct bio *bio = *biop;
unsigned int granularity;
unsigned int op;
int alignment;
sector_t bs_mask;
if (!q)
return -ENXIO;
if (bdev_read_only(bdev))
return -EPERM;
if (flags & BLKDEV_DISCARD_SECURE) {
if (!blk_queue_secure_erase(q))
return -EOPNOTSUPP;
op = REQ_OP_SECURE_ERASE;
} else {
if (!blk_queue_discard(q))
return -EOPNOTSUPP;
op = REQ_OP_DISCARD;
}
bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
/* Zero-sector (unknown) and one-sector granularities are the same. */
granularity = max(q->limits.discard_granularity >> 9, 1U);
alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
while (nr_sects) {
unsigned int req_sects;
sector_t end_sect, tmp;
/* Make sure bi_size doesn't overflow */
req_sects = min_t(sector_t, nr_sects, UINT_MAX >> 9);
/**
* If splitting a request, and the next starting sector would be
* misaligned, stop the discard at the previous aligned sector.
*/
end_sect = sector + req_sects;
tmp = end_sect;
if (req_sects < nr_sects &&
sector_div(tmp, granularity) != alignment) {
end_sect = end_sect - alignment;
sector_div(end_sect, granularity);
end_sect = end_sect * granularity + alignment;
req_sects = end_sect - sector;
}
bio = next_bio(bio, 0, gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio_set_op_attrs(bio, op, 0);
bio->bi_iter.bi_size = req_sects << 9;
nr_sects -= req_sects;
sector = end_sect;
/*
* 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();
}
*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)
* @flags: BLKDEV_DISCARD_* 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)
{
struct bio *bio = NULL;
struct blk_plug plug;
int ret;
blk_start_plug(&plug);
ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
&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);
/**
* __blkdev_issue_write_same - generate number of bios with same page
* @bdev: target blockdev
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
* @page: page containing data to write
* @biop: pointer to anchor bio
*
* Description:
* Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
*/
static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct page *page,
struct bio **biop)
{
struct request_queue *q = bdev_get_queue(bdev);
unsigned int max_write_same_sectors;
struct bio *bio = *biop;
sector_t bs_mask;
if (!q)
return -ENXIO;
if (bdev_read_only(bdev))
return -EPERM;
bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
if (!bdev_write_same(bdev))
return -EOPNOTSUPP;
/* Ensure that max_write_same_sectors doesn't overflow bi_size */
max_write_same_sectors = UINT_MAX >> 9;
while (nr_sects) {
bio = next_bio(bio, 1, gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio->bi_vcnt = 1;
bio->bi_io_vec->bv_page = page;
bio->bi_io_vec->bv_offset = 0;
bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
if (nr_sects > max_write_same_sectors) {
bio->bi_iter.bi_size = max_write_same_sectors << 9;
nr_sects -= max_write_same_sectors;
sector += max_write_same_sectors;
} else {
bio->bi_iter.bi_size = nr_sects << 9;
nr_sects = 0;
}
cond_resched();
}
*biop = bio;
return 0;
}
/**
* blkdev_issue_write_same - queue a write same operation
* @bdev: target blockdev
* @sector: start sector
* @nr_sects: number of sectors to write
* @gfp_mask: memory allocation flags (for bio_alloc)
* @page: page containing data
*
* Description:
* Issue a write same request for the sectors in question.
*/
int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask,
struct page *page)
{
struct bio *bio = NULL;
struct blk_plug plug;
int ret;
blk_start_plug(&plug);
ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
&bio);
if (ret == 0 && bio) {
ret = submit_bio_wait(bio);
bio_put(bio);
}
blk_finish_plug(&plug);
return ret;
}
EXPORT_SYMBOL(blkdev_issue_write_same);
static int __blkdev_issue_write_zeroes(struct block_device *bdev,
sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
struct bio **biop, unsigned flags)
{
struct bio *bio = *biop;
unsigned int max_write_zeroes_sectors;
struct request_queue *q = bdev_get_queue(bdev);
if (!q)
return -ENXIO;
if (bdev_read_only(bdev))
return -EPERM;
/* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
if (max_write_zeroes_sectors == 0)
return -EOPNOTSUPP;
while (nr_sects) {
bio = next_bio(bio, 0, gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio->bi_opf = REQ_OP_WRITE_ZEROES;
if (flags & BLKDEV_ZERO_NOUNMAP)
bio->bi_opf |= REQ_NOUNMAP;
if (nr_sects > max_write_zeroes_sectors) {
bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
nr_sects -= max_write_zeroes_sectors;
sector += max_write_zeroes_sectors;
} else {
bio->bi_iter.bi_size = nr_sects << 9;
nr_sects = 0;
}
cond_resched();
}
*biop = bio;
return 0;
}
/*
* 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_PAGES);
}
static int __blkdev_issue_zero_pages(struct block_device *bdev,
sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
struct bio **biop)
{
struct request_queue *q = bdev_get_queue(bdev);
struct bio *bio = *biop;
int bi_size = 0;
unsigned int sz;
if (!q)
return -ENXIO;
if (bdev_read_only(bdev))
return -EPERM;
while (nr_sects != 0) {
bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
gfp_mask);
bio->bi_iter.bi_sector = sector;
bio_set_dev(bio, bdev);
bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
while (nr_sects != 0) {
sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
nr_sects -= bi_size >> 9;
sector += bi_size >> 9;
if (bi_size < sz)
break;
}
cond_resched();
}
*biop = bio;
return 0;
}
/**
* __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)
{
int ret;
sector_t bs_mask;
bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
biop, flags);
if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
return ret;
return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
biop);
}
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 = 0;
sector_t bs_mask;
struct bio *bio;
struct blk_plug plug;
bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
if ((sector | nr_sects) & bs_mask)
return -EINVAL;
retry:
bio = NULL;
blk_start_plug(&plug);
if (try_write_zeroes) {
ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
gfp_mask, &bio, flags);
} else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
gfp_mask, &bio);
} else {
/* No zeroing offload support */
ret = -EOPNOTSUPP;
}
if (ret == 0 && bio) {
ret = submit_bio_wait(bio);
bio_put(bio);
}
blk_finish_plug(&plug);
if (ret && try_write_zeroes) {
if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
try_write_zeroes = false;
goto retry;
}
if (!bdev_write_zeroes_sectors(bdev)) {
/*
* Zeroing offload support was indicated, but the
* device reported ILLEGAL REQUEST (for some devices
* there is no non-destructive way to verify whether
* WRITE ZEROES is actually supported).
*/
ret = -EOPNOTSUPP;
}
}
return ret;
}
EXPORT_SYMBOL(blkdev_issue_zeroout);
