443 lines
11 KiB
C
443 lines
11 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Functions related to generic helpers functions
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/scatterlist.h>
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#include "blk.h"
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static struct bio *next_bio(struct bio *bio, unsigned int nr_pages,
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gfp_t gfp)
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{
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struct bio *new = bio_alloc(gfp, nr_pages);
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if (bio) {
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bio_chain(bio, new);
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submit_bio(bio);
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}
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return new;
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}
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int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
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sector_t nr_sects, gfp_t gfp_mask, int flags,
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struct bio **biop)
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{
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struct request_queue *q = bdev_get_queue(bdev);
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struct bio *bio = *biop;
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unsigned int granularity;
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unsigned int op;
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int alignment;
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sector_t bs_mask;
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if (!q)
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return -ENXIO;
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if (bdev_read_only(bdev))
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return -EPERM;
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if (flags & BLKDEV_DISCARD_SECURE) {
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if (!blk_queue_secure_erase(q))
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return -EOPNOTSUPP;
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op = REQ_OP_SECURE_ERASE;
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} else {
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if (!blk_queue_discard(q))
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return -EOPNOTSUPP;
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op = REQ_OP_DISCARD;
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}
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bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
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if ((sector | nr_sects) & bs_mask)
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return -EINVAL;
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/* Zero-sector (unknown) and one-sector granularities are the same. */
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granularity = max(q->limits.discard_granularity >> 9, 1U);
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alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
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while (nr_sects) {
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unsigned int req_sects;
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sector_t end_sect, tmp;
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/*
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* Issue in chunks of the user defined max discard setting,
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* ensuring that bi_size doesn't overflow
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*/
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req_sects = min_t(sector_t, nr_sects,
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q->limits.max_discard_sectors);
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if (!req_sects)
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goto fail;
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if (req_sects > UINT_MAX >> 9)
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req_sects = UINT_MAX >> 9;
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/*
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* If splitting a request, and the next starting sector would be
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* misaligned, stop the discard at the previous aligned sector.
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*/
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end_sect = sector + req_sects;
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tmp = end_sect;
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if (req_sects < nr_sects &&
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sector_div(tmp, granularity) != alignment) {
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end_sect = end_sect - alignment;
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sector_div(end_sect, granularity);
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end_sect = end_sect * granularity + alignment;
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req_sects = end_sect - sector;
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}
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bio = next_bio(bio, 0, gfp_mask);
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bio->bi_iter.bi_sector = sector;
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bio_set_dev(bio, bdev);
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bio_set_op_attrs(bio, op, 0);
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bio->bi_iter.bi_size = req_sects << 9;
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nr_sects -= req_sects;
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sector = end_sect;
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/*
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* We can loop for a long time in here, if someone does
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* full device discards (like mkfs). Be nice and allow
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* us to schedule out to avoid softlocking if preempt
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* is disabled.
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*/
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cond_resched();
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}
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*biop = bio;
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return 0;
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fail:
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if (bio) {
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submit_bio_wait(bio);
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bio_put(bio);
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}
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*biop = NULL;
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return -EOPNOTSUPP;
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}
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EXPORT_SYMBOL(__blkdev_issue_discard);
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/**
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* blkdev_issue_discard - queue a discard
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* @bdev: blockdev to issue discard for
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* @sector: start sector
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* @nr_sects: number of sectors to discard
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* @gfp_mask: memory allocation flags (for bio_alloc)
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* @flags: BLKDEV_DISCARD_* flags to control behaviour
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*
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* Description:
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* Issue a discard request for the sectors in question.
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*/
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int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
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sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
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{
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struct bio *bio = NULL;
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struct blk_plug plug;
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int ret;
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blk_start_plug(&plug);
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ret = __blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, flags,
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&bio);
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if (!ret && bio) {
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ret = submit_bio_wait(bio);
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if (ret == -EOPNOTSUPP)
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ret = 0;
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bio_put(bio);
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}
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blk_finish_plug(&plug);
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return ret;
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}
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EXPORT_SYMBOL(blkdev_issue_discard);
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/**
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* __blkdev_issue_write_same - generate number of bios with same page
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* @bdev: target blockdev
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* @sector: start sector
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* @nr_sects: number of sectors to write
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* @gfp_mask: memory allocation flags (for bio_alloc)
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* @page: page containing data to write
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* @biop: pointer to anchor bio
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*
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* Description:
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* Generate and issue number of bios(REQ_OP_WRITE_SAME) with same page.
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*/
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static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
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sector_t nr_sects, gfp_t gfp_mask, struct page *page,
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struct bio **biop)
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{
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struct request_queue *q = bdev_get_queue(bdev);
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unsigned int max_write_same_sectors;
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struct bio *bio = *biop;
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sector_t bs_mask;
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if (!q)
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return -ENXIO;
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if (bdev_read_only(bdev))
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return -EPERM;
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bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
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if ((sector | nr_sects) & bs_mask)
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return -EINVAL;
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if (!bdev_write_same(bdev))
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return -EOPNOTSUPP;
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/* Ensure that max_write_same_sectors doesn't overflow bi_size */
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max_write_same_sectors = UINT_MAX >> 9;
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while (nr_sects) {
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bio = next_bio(bio, 1, gfp_mask);
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bio->bi_iter.bi_sector = sector;
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bio_set_dev(bio, bdev);
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bio->bi_vcnt = 1;
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bio->bi_io_vec->bv_page = page;
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bio->bi_io_vec->bv_offset = 0;
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bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
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bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
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if (nr_sects > max_write_same_sectors) {
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bio->bi_iter.bi_size = max_write_same_sectors << 9;
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nr_sects -= max_write_same_sectors;
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sector += max_write_same_sectors;
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} else {
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bio->bi_iter.bi_size = nr_sects << 9;
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nr_sects = 0;
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}
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cond_resched();
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}
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*biop = bio;
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return 0;
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}
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/**
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* blkdev_issue_write_same - queue a write same operation
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* @bdev: target blockdev
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* @sector: start sector
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* @nr_sects: number of sectors to write
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* @gfp_mask: memory allocation flags (for bio_alloc)
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* @page: page containing data
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*
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* Description:
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* Issue a write same request for the sectors in question.
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*/
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int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
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sector_t nr_sects, gfp_t gfp_mask,
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struct page *page)
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{
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struct bio *bio = NULL;
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struct blk_plug plug;
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int ret;
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blk_start_plug(&plug);
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ret = __blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, page,
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&bio);
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if (ret == 0 && bio) {
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ret = submit_bio_wait(bio);
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bio_put(bio);
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}
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blk_finish_plug(&plug);
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return ret;
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}
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EXPORT_SYMBOL(blkdev_issue_write_same);
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static int __blkdev_issue_write_zeroes(struct block_device *bdev,
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sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
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struct bio **biop, unsigned flags)
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{
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struct bio *bio = *biop;
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unsigned int max_write_zeroes_sectors;
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struct request_queue *q = bdev_get_queue(bdev);
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if (!q)
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return -ENXIO;
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if (bdev_read_only(bdev))
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return -EPERM;
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/* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */
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max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev);
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if (max_write_zeroes_sectors == 0)
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return -EOPNOTSUPP;
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while (nr_sects) {
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bio = next_bio(bio, 0, gfp_mask);
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bio->bi_iter.bi_sector = sector;
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bio_set_dev(bio, bdev);
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bio->bi_opf = REQ_OP_WRITE_ZEROES;
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if (flags & BLKDEV_ZERO_NOUNMAP)
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bio->bi_opf |= REQ_NOUNMAP;
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if (nr_sects > max_write_zeroes_sectors) {
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bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
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nr_sects -= max_write_zeroes_sectors;
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sector += max_write_zeroes_sectors;
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} else {
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bio->bi_iter.bi_size = nr_sects << 9;
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nr_sects = 0;
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}
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cond_resched();
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}
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*biop = bio;
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return 0;
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}
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/*
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* Convert a number of 512B sectors to a number of pages.
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* The result is limited to a number of pages that can fit into a BIO.
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* Also make sure that the result is always at least 1 (page) for the cases
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* where nr_sects is lower than the number of sectors in a page.
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*/
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static unsigned int __blkdev_sectors_to_bio_pages(sector_t nr_sects)
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{
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sector_t pages = DIV_ROUND_UP_SECTOR_T(nr_sects, PAGE_SIZE / 512);
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return min(pages, (sector_t)BIO_MAX_PAGES);
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}
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static int __blkdev_issue_zero_pages(struct block_device *bdev,
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sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
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struct bio **biop)
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{
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struct request_queue *q = bdev_get_queue(bdev);
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struct bio *bio = *biop;
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int bi_size = 0;
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unsigned int sz;
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if (!q)
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return -ENXIO;
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if (bdev_read_only(bdev))
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return -EPERM;
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while (nr_sects != 0) {
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bio = next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
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gfp_mask);
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bio->bi_iter.bi_sector = sector;
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bio_set_dev(bio, bdev);
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bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
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while (nr_sects != 0) {
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sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
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bi_size = bio_add_page(bio, ZERO_PAGE(0), sz, 0);
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nr_sects -= bi_size >> 9;
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sector += bi_size >> 9;
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if (bi_size < sz)
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break;
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}
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cond_resched();
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}
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*biop = bio;
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return 0;
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}
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/**
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* __blkdev_issue_zeroout - generate number of zero filed write bios
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* @bdev: blockdev to issue
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* @sector: start sector
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* @nr_sects: number of sectors to write
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* @gfp_mask: memory allocation flags (for bio_alloc)
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* @biop: pointer to anchor bio
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* @flags: controls detailed behavior
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*
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* Description:
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* Zero-fill a block range, either using hardware offload or by explicitly
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* writing zeroes to the device.
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*
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* If a device is using logical block provisioning, the underlying space will
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* not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
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*
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* If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
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* -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
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*/
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int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
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sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
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unsigned flags)
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{
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int ret;
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sector_t bs_mask;
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bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
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if ((sector | nr_sects) & bs_mask)
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return -EINVAL;
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ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
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biop, flags);
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if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
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return ret;
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return __blkdev_issue_zero_pages(bdev, sector, nr_sects, gfp_mask,
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biop);
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}
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EXPORT_SYMBOL(__blkdev_issue_zeroout);
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/**
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* blkdev_issue_zeroout - zero-fill a block range
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* @bdev: blockdev to write
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* @sector: start sector
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* @nr_sects: number of sectors to write
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* @gfp_mask: memory allocation flags (for bio_alloc)
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* @flags: controls detailed behavior
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*
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* Description:
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* Zero-fill a block range, either using hardware offload or by explicitly
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* writing zeroes to the device. See __blkdev_issue_zeroout() for the
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* valid values for %flags.
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*/
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int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
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sector_t nr_sects, gfp_t gfp_mask, unsigned flags)
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{
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int ret = 0;
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sector_t bs_mask;
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struct bio *bio;
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struct blk_plug plug;
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bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev);
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bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1;
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if ((sector | nr_sects) & bs_mask)
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return -EINVAL;
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retry:
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bio = NULL;
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blk_start_plug(&plug);
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if (try_write_zeroes) {
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ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects,
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gfp_mask, &bio, flags);
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} else if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
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ret = __blkdev_issue_zero_pages(bdev, sector, nr_sects,
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gfp_mask, &bio);
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} else {
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/* No zeroing offload support */
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ret = -EOPNOTSUPP;
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}
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if (ret == 0 && bio) {
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ret = submit_bio_wait(bio);
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bio_put(bio);
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}
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blk_finish_plug(&plug);
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if (ret && try_write_zeroes) {
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if (!(flags & BLKDEV_ZERO_NOFALLBACK)) {
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try_write_zeroes = false;
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goto retry;
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}
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if (!bdev_write_zeroes_sectors(bdev)) {
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/*
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* Zeroing offload support was indicated, but the
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* device reported ILLEGAL REQUEST (for some devices
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* there is no non-destructive way to verify whether
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* WRITE ZEROES is actually supported).
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*/
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ret = -EOPNOTSUPP;
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}
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}
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return ret;
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}
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EXPORT_SYMBOL(blkdev_issue_zeroout);
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