302 lines
7.1 KiB
C
302 lines
7.1 KiB
C
/*
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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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struct bio_batch {
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atomic_t done;
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unsigned long flags;
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struct completion *wait;
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};
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static void bio_batch_end_io(struct bio *bio, int err)
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{
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struct bio_batch *bb = bio->bi_private;
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if (err && (err != -EOPNOTSUPP))
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clear_bit(BIO_UPTODATE, &bb->flags);
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if (atomic_dec_and_test(&bb->done))
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complete(bb->wait);
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bio_put(bio);
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}
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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_IFL_* 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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DECLARE_COMPLETION_ONSTACK(wait);
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struct request_queue *q = bdev_get_queue(bdev);
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int type = REQ_WRITE | REQ_DISCARD;
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sector_t max_discard_sectors;
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sector_t granularity, alignment;
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struct bio_batch bb;
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struct bio *bio;
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int ret = 0;
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struct blk_plug plug;
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if (!q)
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return -ENXIO;
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if (!blk_queue_discard(q))
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return -EOPNOTSUPP;
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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;
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alignment = sector_div(alignment, granularity);
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/*
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* Ensure that max_discard_sectors is of the proper
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* granularity, so that requests stay aligned after a split.
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*/
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max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
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sector_div(max_discard_sectors, granularity);
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max_discard_sectors *= granularity;
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if (unlikely(!max_discard_sectors)) {
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/* Avoid infinite loop below. Being cautious never hurts. */
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return -EOPNOTSUPP;
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}
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if (flags & BLKDEV_DISCARD_SECURE) {
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if (!blk_queue_secdiscard(q))
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return -EOPNOTSUPP;
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type |= REQ_SECURE;
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}
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atomic_set(&bb.done, 1);
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bb.flags = 1 << BIO_UPTODATE;
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bb.wait = &wait;
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blk_start_plug(&plug);
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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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bio = bio_alloc(gfp_mask, 1);
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if (!bio) {
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ret = -ENOMEM;
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break;
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}
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req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
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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->bi_sector = sector;
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bio->bi_end_io = bio_batch_end_io;
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bio->bi_bdev = bdev;
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bio->bi_private = &bb;
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bio->bi_size = req_sects << 9;
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nr_sects -= req_sects;
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sector = end_sect;
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atomic_inc(&bb.done);
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submit_bio(type, bio);
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}
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blk_finish_plug(&plug);
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/* Wait for bios in-flight */
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if (!atomic_dec_and_test(&bb.done))
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wait_for_completion(&wait);
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if (!test_bit(BIO_UPTODATE, &bb.flags))
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ret = -EIO;
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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 - 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 to write
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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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DECLARE_COMPLETION_ONSTACK(wait);
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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_batch bb;
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struct bio *bio;
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int ret = 0;
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if (!q)
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return -ENXIO;
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max_write_same_sectors = q->limits.max_write_same_sectors;
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if (max_write_same_sectors == 0)
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return -EOPNOTSUPP;
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atomic_set(&bb.done, 1);
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bb.flags = 1 << BIO_UPTODATE;
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bb.wait = &wait;
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while (nr_sects) {
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bio = bio_alloc(gfp_mask, 1);
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if (!bio) {
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ret = -ENOMEM;
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break;
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}
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bio->bi_sector = sector;
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bio->bi_end_io = bio_batch_end_io;
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bio->bi_bdev = bdev;
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bio->bi_private = &bb;
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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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if (nr_sects > max_write_same_sectors) {
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bio->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_size = nr_sects << 9;
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nr_sects = 0;
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}
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atomic_inc(&bb.done);
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submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
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}
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/* Wait for bios in-flight */
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if (!atomic_dec_and_test(&bb.done))
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wait_for_completion(&wait);
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if (!test_bit(BIO_UPTODATE, &bb.flags))
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ret = -ENOTSUPP;
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return ret;
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}
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EXPORT_SYMBOL(blkdev_issue_write_same);
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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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*
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* Description:
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* Generate and issue number of bios with zerofiled pages.
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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)
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{
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int ret;
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struct bio *bio;
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struct bio_batch bb;
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unsigned int sz;
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DECLARE_COMPLETION_ONSTACK(wait);
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atomic_set(&bb.done, 1);
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bb.flags = 1 << BIO_UPTODATE;
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bb.wait = &wait;
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ret = 0;
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while (nr_sects != 0) {
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bio = bio_alloc(gfp_mask,
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min(nr_sects, (sector_t)BIO_MAX_PAGES));
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if (!bio) {
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ret = -ENOMEM;
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break;
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}
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bio->bi_sector = sector;
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bio->bi_bdev = bdev;
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bio->bi_end_io = bio_batch_end_io;
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bio->bi_private = &bb;
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while (nr_sects != 0) {
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sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
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ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
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nr_sects -= ret >> 9;
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sector += ret >> 9;
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if (ret < (sz << 9))
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break;
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}
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ret = 0;
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atomic_inc(&bb.done);
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submit_bio(WRITE, bio);
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}
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/* Wait for bios in-flight */
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if (!atomic_dec_and_test(&bb.done))
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wait_for_completion(&wait);
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if (!test_bit(BIO_UPTODATE, &bb.flags))
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/* One of bios in the batch was completed with error.*/
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ret = -EIO;
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return ret;
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}
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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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*
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* Description:
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* Generate and issue number of bios with zerofiled pages.
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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)
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{
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if (bdev_write_same(bdev)) {
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unsigned char bdn[BDEVNAME_SIZE];
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if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
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ZERO_PAGE(0)))
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return 0;
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bdevname(bdev, bdn);
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pr_err("%s: WRITE SAME failed. Manually zeroing.\n", bdn);
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}
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return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
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}
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EXPORT_SYMBOL(blkdev_issue_zeroout);
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