block/blk-lib.c - kernel/msm-4.9 - Gitiles

 /*
  * 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"

 struct bio_batch {
 	atomic_t		done;
 	int			error;
 	struct completion	*wait;
 };

 static void bio_batch_end_io(struct bio *bio)
 {
 	struct bio_batch *bb = bio->bi_private;

 	if (bio->bi_error && bio->bi_error != -EOPNOTSUPP)
 		bb->error = bio->bi_error;
 	if (atomic_dec_and_test(&bb->done))
 		complete(bb->wait);
 	bio_put(bio);
 }

 /**
  * 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_IFL_* 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)
 {
 	DECLARE_COMPLETION_ONSTACK(wait);
 	struct request_queue *q = bdev_get_queue(bdev);
 	int type = REQ_WRITE | REQ_DISCARD;
 	unsigned int granularity;
 	int alignment;
 	struct bio_batch bb;
 	struct bio *bio;
 	int ret = 0;
 	struct blk_plug plug;

 	if (!q)
 		return -ENXIO;

 	if (!blk_queue_discard(q))
 		return -EOPNOTSUPP;

 	/* 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;

 	if (flags & BLKDEV_DISCARD_SECURE) {
 		if (!blk_queue_secdiscard(q))
 			return -EOPNOTSUPP;
 		type |= REQ_SECURE;
 	}

 	atomic_set(&bb.done, 1);
 	bb.error = 0;
 	bb.wait = &wait;

 	blk_start_plug(&plug);
 	while (nr_sects) {
 		unsigned int req_sects;
 		sector_t end_sect, tmp;

 		bio = bio_alloc(gfp_mask, 1);
 		if (!bio) {
 			ret = -ENOMEM;
 			break;
 		}

 		/* 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->bi_iter.bi_sector = sector;
 		bio->bi_end_io = bio_batch_end_io;
 		bio->bi_bdev = bdev;
 		bio->bi_private = &bb;

 		bio->bi_iter.bi_size = req_sects << 9;
 		nr_sects -= req_sects;
 		sector = end_sect;

 		atomic_inc(&bb.done);
 		submit_bio(type, bio);

 		/*
 		 * 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();
 	}
 	blk_finish_plug(&plug);

 	/* Wait for bios in-flight */
 	if (!atomic_dec_and_test(&bb.done))
 		wait_for_completion_io(&wait);

 	if (bb.error)
 		return bb.error;
 	return ret;
 }
 EXPORT_SYMBOL(blkdev_issue_discard);

 /**
  * 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 to write
  *
  * 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)
 {
 	DECLARE_COMPLETION_ONSTACK(wait);
 	struct request_queue *q = bdev_get_queue(bdev);
 	unsigned int max_write_same_sectors;
 	struct bio_batch bb;
 	struct bio *bio;
 	int ret = 0;

 	if (!q)
 		return -ENXIO;

 	/* Ensure that max_write_same_sectors doesn't overflow bi_size */
 	max_write_same_sectors = UINT_MAX >> 9;

 	atomic_set(&bb.done, 1);
 	bb.error = 0;
 	bb.wait = &wait;

 	while (nr_sects) {
 		bio = bio_alloc(gfp_mask, 1);
 		if (!bio) {
 			ret = -ENOMEM;
 			break;
 		}

 		bio->bi_iter.bi_sector = sector;
 		bio->bi_end_io = bio_batch_end_io;
 		bio->bi_bdev = bdev;
 		bio->bi_private = &bb;
 		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);

 		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;
 		}

 		atomic_inc(&bb.done);
 		submit_bio(REQ_WRITE | REQ_WRITE_SAME, bio);
 	}

 	/* Wait for bios in-flight */
 	if (!atomic_dec_and_test(&bb.done))
 		wait_for_completion_io(&wait);

 	if (bb.error)
 		return bb.error;
 	return ret;
 }
 EXPORT_SYMBOL(blkdev_issue_write_same);

 /**
  * 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)
  *
  * Description:
  *  Generate and issue number of bios with zerofiled pages.
  */

 static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 				  sector_t nr_sects, gfp_t gfp_mask)
 {
 	int ret;
 	struct bio *bio;
 	struct bio_batch bb;
 	unsigned int sz;
 	DECLARE_COMPLETION_ONSTACK(wait);

 	atomic_set(&bb.done, 1);
 	bb.error = 0;
 	bb.wait = &wait;

 	ret = 0;
 	while (nr_sects != 0) {
 		bio = bio_alloc(gfp_mask,
 				min(nr_sects, (sector_t)BIO_MAX_PAGES));
 		if (!bio) {
 			ret = -ENOMEM;
 			break;
 		}

 		bio->bi_iter.bi_sector = sector;
 		bio->bi_bdev   = bdev;
 		bio->bi_end_io = bio_batch_end_io;
 		bio->bi_private = &bb;

 		while (nr_sects != 0) {
 			sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
 			ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
 			nr_sects -= ret >> 9;
 			sector += ret >> 9;
 			if (ret < (sz << 9))
 				break;
 		}
 		ret = 0;
 		atomic_inc(&bb.done);
 		submit_bio(WRITE, bio);
 	}

 	/* Wait for bios in-flight */
 	if (!atomic_dec_and_test(&bb.done))
 		wait_for_completion_io(&wait);

 	if (bb.error)
 		return bb.error;
 	return ret;
 }

 /**
  * 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)
  * @discard:	whether to discard the block range
  *
  * Description:
  *  Zero-fill a block range.  If the discard flag is set and the block
  *  device guarantees that subsequent READ operations to the block range
  *  in question will return zeroes, the blocks will be discarded. Should
  *  the discard request fail, if the discard flag is not set, or if
  *  discard_zeroes_data is not supported, this function will resort to
  *  zeroing the blocks manually, thus provisioning (allocating,
  *  anchoring) them. If the block device supports the WRITE SAME command
  *  blkdev_issue_zeroout() will use it to optimize the process of
  *  clearing the block range. Otherwise the zeroing will be performed
  *  using regular WRITE calls.
  */

 int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
 			 sector_t nr_sects, gfp_t gfp_mask, bool discard)
 {
 	struct request_queue *q = bdev_get_queue(bdev);

 	if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
 	    blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
 		return 0;

 	if (bdev_write_same(bdev) &&
 	    blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
 				    ZERO_PAGE(0)) == 0)
 		return 0;

 	return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
 }
 EXPORT_SYMBOL(blkdev_issue_zeroout);
	/*
	* 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"

	struct bio_batch {
	atomic_t done;
	int error;
	struct completion *wait;
	};

	static void bio_batch_end_io(struct bio *bio)
	{
	struct bio_batch *bb = bio->bi_private;

	if (bio->bi_error && bio->bi_error != -EOPNOTSUPP)
	bb->error = bio->bi_error;
	if (atomic_dec_and_test(&bb->done))
	complete(bb->wait);
	bio_put(bio);
	}

	/**
	* 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_IFL_* 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)
	{
	DECLARE_COMPLETION_ONSTACK(wait);
	struct request_queue *q = bdev_get_queue(bdev);
	int type = REQ_WRITE \| REQ_DISCARD;
	unsigned int granularity;
	int alignment;
	struct bio_batch bb;
	struct bio *bio;
	int ret = 0;
	struct blk_plug plug;

	if (!q)
	return -ENXIO;

	if (!blk_queue_discard(q))
	return -EOPNOTSUPP;

	/* 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;

	if (flags & BLKDEV_DISCARD_SECURE) {
	if (!blk_queue_secdiscard(q))
	return -EOPNOTSUPP;
	type \|= REQ_SECURE;
	}

	atomic_set(&bb.done, 1);
	bb.error = 0;
	bb.wait = &wait;

	blk_start_plug(&plug);
	while (nr_sects) {
	unsigned int req_sects;
	sector_t end_sect, tmp;

	bio = bio_alloc(gfp_mask, 1);
	if (!bio) {
	ret = -ENOMEM;
	break;
	}

	/* 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->bi_iter.bi_sector = sector;
	bio->bi_end_io = bio_batch_end_io;
	bio->bi_bdev = bdev;
	bio->bi_private = &bb;

	bio->bi_iter.bi_size = req_sects << 9;
	nr_sects -= req_sects;
	sector = end_sect;

	atomic_inc(&bb.done);
	submit_bio(type, bio);

	/*
	* 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();
	}
	blk_finish_plug(&plug);

	/* Wait for bios in-flight */
	if (!atomic_dec_and_test(&bb.done))
	wait_for_completion_io(&wait);

	if (bb.error)
	return bb.error;
	return ret;
	}
	EXPORT_SYMBOL(blkdev_issue_discard);

	/**
	* 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 to write
	*
	* 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)
	{
	DECLARE_COMPLETION_ONSTACK(wait);
	struct request_queue *q = bdev_get_queue(bdev);
	unsigned int max_write_same_sectors;
	struct bio_batch bb;
	struct bio *bio;
	int ret = 0;

	if (!q)
	return -ENXIO;

	/* Ensure that max_write_same_sectors doesn't overflow bi_size */
	max_write_same_sectors = UINT_MAX >> 9;

	atomic_set(&bb.done, 1);
	bb.error = 0;
	bb.wait = &wait;

	while (nr_sects) {
	bio = bio_alloc(gfp_mask, 1);
	if (!bio) {
	ret = -ENOMEM;
	break;
	}

	bio->bi_iter.bi_sector = sector;
	bio->bi_end_io = bio_batch_end_io;
	bio->bi_bdev = bdev;
	bio->bi_private = &bb;
	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);

	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;
	}

	atomic_inc(&bb.done);
	submit_bio(REQ_WRITE \| REQ_WRITE_SAME, bio);
	}

	/* Wait for bios in-flight */
	if (!atomic_dec_and_test(&bb.done))
	wait_for_completion_io(&wait);

	if (bb.error)
	return bb.error;
	return ret;
	}
	EXPORT_SYMBOL(blkdev_issue_write_same);

	/**
	* 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)
	*
	* Description:
	* Generate and issue number of bios with zerofiled pages.
	*/

	static int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
	sector_t nr_sects, gfp_t gfp_mask)
	{
	int ret;
	struct bio *bio;
	struct bio_batch bb;
	unsigned int sz;
	DECLARE_COMPLETION_ONSTACK(wait);

	atomic_set(&bb.done, 1);
	bb.error = 0;
	bb.wait = &wait;

	ret = 0;
	while (nr_sects != 0) {
	bio = bio_alloc(gfp_mask,
	min(nr_sects, (sector_t)BIO_MAX_PAGES));
	if (!bio) {
	ret = -ENOMEM;
	break;
	}

	bio->bi_iter.bi_sector = sector;
	bio->bi_bdev = bdev;
	bio->bi_end_io = bio_batch_end_io;
	bio->bi_private = &bb;

	while (nr_sects != 0) {
	sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
	ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
	nr_sects -= ret >> 9;
	sector += ret >> 9;
	if (ret < (sz << 9))
	break;
	}
	ret = 0;
	atomic_inc(&bb.done);
	submit_bio(WRITE, bio);
	}

	/* Wait for bios in-flight */
	if (!atomic_dec_and_test(&bb.done))
	wait_for_completion_io(&wait);

	if (bb.error)
	return bb.error;
	return ret;
	}

	/**
	* 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)
	* @discard: whether to discard the block range
	*
	* Description:
	* Zero-fill a block range. If the discard flag is set and the block
	* device guarantees that subsequent READ operations to the block range
	* in question will return zeroes, the blocks will be discarded. Should
	* the discard request fail, if the discard flag is not set, or if
	* discard_zeroes_data is not supported, this function will resort to
	* zeroing the blocks manually, thus provisioning (allocating,
	* anchoring) them. If the block device supports the WRITE SAME command
	* blkdev_issue_zeroout() will use it to optimize the process of
	* clearing the block range. Otherwise the zeroing will be performed
	* using regular WRITE calls.
	*/

	int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
	sector_t nr_sects, gfp_t gfp_mask, bool discard)
	{
	struct request_queue *q = bdev_get_queue(bdev);

	if (discard && blk_queue_discard(q) && q->limits.discard_zeroes_data &&
	blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask, 0) == 0)
	return 0;

	if (bdev_write_same(bdev) &&
	blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask,
	ZERO_PAGE(0)) == 0)
	return 0;

	return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
	}
	EXPORT_SYMBOL(blkdev_issue_zeroout);