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/block/blk-lib.c

https://bitbucket.org/ndreys/linux-sunxi
C | 175 lines | 117 code | 27 blank | 31 comment | 23 complexity | 60a03f2cb22bedf98b3c213c67fdb516 MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.0, AGPL-1.0
  1/*
  2 * Functions related to generic helpers functions
  3 */
  4#include <linux/kernel.h>
  5#include <linux/module.h>
  6#include <linux/bio.h>
  7#include <linux/blkdev.h>
  8#include <linux/scatterlist.h>
  9
 10#include "blk.h"
 11
 12struct bio_batch {
 13	atomic_t		done;
 14	unsigned long		flags;
 15	struct completion	*wait;
 16};
 17
 18static void bio_batch_end_io(struct bio *bio, int err)
 19{
 20	struct bio_batch *bb = bio->bi_private;
 21
 22	if (err && (err != -EOPNOTSUPP))
 23		clear_bit(BIO_UPTODATE, &bb->flags);
 24	if (atomic_dec_and_test(&bb->done))
 25		complete(bb->wait);
 26	bio_put(bio);
 27}
 28
 29/**
 30 * blkdev_issue_discard - queue a discard
 31 * @bdev:	blockdev to issue discard for
 32 * @sector:	start sector
 33 * @nr_sects:	number of sectors to discard
 34 * @gfp_mask:	memory allocation flags (for bio_alloc)
 35 * @flags:	BLKDEV_IFL_* flags to control behaviour
 36 *
 37 * Description:
 38 *    Issue a discard request for the sectors in question.
 39 */
 40int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 41		sector_t nr_sects, gfp_t gfp_mask, unsigned long flags)
 42{
 43	DECLARE_COMPLETION_ONSTACK(wait);
 44	struct request_queue *q = bdev_get_queue(bdev);
 45	int type = REQ_WRITE | REQ_DISCARD;
 46	unsigned int max_discard_sectors;
 47	struct bio_batch bb;
 48	struct bio *bio;
 49	int ret = 0;
 50
 51	if (!q)
 52		return -ENXIO;
 53
 54	if (!blk_queue_discard(q))
 55		return -EOPNOTSUPP;
 56
 57	/*
 58	 * Ensure that max_discard_sectors is of the proper
 59	 * granularity
 60	 */
 61	max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
 62	if (q->limits.discard_granularity) {
 63		unsigned int disc_sects = q->limits.discard_granularity >> 9;
 64
 65		max_discard_sectors &= ~(disc_sects - 1);
 66	}
 67
 68	if (flags & BLKDEV_DISCARD_SECURE) {
 69		if (!blk_queue_secdiscard(q))
 70			return -EOPNOTSUPP;
 71		type |= REQ_SECURE;
 72	}
 73
 74	atomic_set(&bb.done, 1);
 75	bb.flags = 1 << BIO_UPTODATE;
 76	bb.wait = &wait;
 77
 78	while (nr_sects) {
 79		bio = bio_alloc(gfp_mask, 1);
 80		if (!bio) {
 81			ret = -ENOMEM;
 82			break;
 83		}
 84
 85		bio->bi_sector = sector;
 86		bio->bi_end_io = bio_batch_end_io;
 87		bio->bi_bdev = bdev;
 88		bio->bi_private = &bb;
 89
 90		if (nr_sects > max_discard_sectors) {
 91			bio->bi_size = max_discard_sectors << 9;
 92			nr_sects -= max_discard_sectors;
 93			sector += max_discard_sectors;
 94		} else {
 95			bio->bi_size = nr_sects << 9;
 96			nr_sects = 0;
 97		}
 98
 99		atomic_inc(&bb.done);
100		submit_bio(type, bio);
101	}
102
103	/* Wait for bios in-flight */
104	if (!atomic_dec_and_test(&bb.done))
105		wait_for_completion(&wait);
106
107	if (!test_bit(BIO_UPTODATE, &bb.flags))
108		ret = -EIO;
109
110	return ret;
111}
112EXPORT_SYMBOL(blkdev_issue_discard);
113
114/**
115 * blkdev_issue_zeroout - generate number of zero filed write bios
116 * @bdev:	blockdev to issue
117 * @sector:	start sector
118 * @nr_sects:	number of sectors to write
119 * @gfp_mask:	memory allocation flags (for bio_alloc)
120 *
121 * Description:
122 *  Generate and issue number of bios with zerofiled pages.
123 */
124
125int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
126			sector_t nr_sects, gfp_t gfp_mask)
127{
128	int ret;
129	struct bio *bio;
130	struct bio_batch bb;
131	unsigned int sz;
132	DECLARE_COMPLETION_ONSTACK(wait);
133
134	atomic_set(&bb.done, 1);
135	bb.flags = 1 << BIO_UPTODATE;
136	bb.wait = &wait;
137
138	ret = 0;
139	while (nr_sects != 0) {
140		bio = bio_alloc(gfp_mask,
141				min(nr_sects, (sector_t)BIO_MAX_PAGES));
142		if (!bio) {
143			ret = -ENOMEM;
144			break;
145		}
146
147		bio->bi_sector = sector;
148		bio->bi_bdev   = bdev;
149		bio->bi_end_io = bio_batch_end_io;
150		bio->bi_private = &bb;
151
152		while (nr_sects != 0) {
153			sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
154			ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
155			nr_sects -= ret >> 9;
156			sector += ret >> 9;
157			if (ret < (sz << 9))
158				break;
159		}
160		ret = 0;
161		atomic_inc(&bb.done);
162		submit_bio(WRITE, bio);
163	}
164
165	/* Wait for bios in-flight */
166	if (!atomic_dec_and_test(&bb.done))
167		wait_for_completion(&wait);
168
169	if (!test_bit(BIO_UPTODATE, &bb.flags))
170		/* One of bios in the batch was completed with error.*/
171		ret = -EIO;
172
173	return ret;
174}
175EXPORT_SYMBOL(blkdev_issue_zeroout);