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Commit aa4d8616 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Al Viro
Browse files

block: loop: switch to VFS ITER_BVEC 



Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 6683de38

drivers/block/loop.c

+120 −174
Original line number Diff line number Diff line
@@ -88,28 +88,6 @@ static int part_shift; 


static struct workqueue_struct *loop_wq;



/*

 * Transfer functions

 */

static int transfer_none(struct loop_device *lo, int cmd,

			 struct page *raw_page, unsigned raw_off,

			 struct page *loop_page, unsigned loop_off,

			 int size, sector_t real_block)

{

	char *raw_buf = kmap_atomic(raw_page) + raw_off;

	char *loop_buf = kmap_atomic(loop_page) + loop_off;



	if (cmd == READ)

		memcpy(loop_buf, raw_buf, size);

	else

		memcpy(raw_buf, loop_buf, size);



	kunmap_atomic(loop_buf);

	kunmap_atomic(raw_buf);

	cond_resched();

	return 0;

}



static int transfer_xor(struct loop_device *lo, int cmd,

			struct page *raw_page, unsigned raw_off,

			struct page *loop_page, unsigned loop_off,
@@ -148,7 +126,6 @@ static int xor_init(struct loop_device *lo, const struct loop_info64 *info) 


static struct loop_func_table none_funcs = {

	.number = LO_CRYPT_NONE,

	.transfer = transfer_none,

}; 



static struct loop_func_table xor_funcs = {
@@ -215,207 +192,169 @@ lo_do_transfer(struct loop_device *lo, int cmd, 
	       struct page *lpage, unsigned loffs,

	       int size, sector_t rblock)

{

	if (unlikely(!lo->transfer))

	int ret;



	ret = lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);

	if (likely(!ret))

		return 0;



	return lo->transfer(lo, cmd, rpage, roffs, lpage, loffs, size, rblock);

	printk_ratelimited(KERN_ERR

		"loop: Transfer error at byte offset %llu, length %i.\n",

		(unsigned long long)rblock << 9, size);

	return ret;

}



/**

 * __do_lo_send_write - helper for writing data to a loop device

 *

 * This helper just factors out common code between do_lo_send_direct_write()

 * and do_lo_send_write().

 */

static int __do_lo_send_write(struct file *file,

		u8 *buf, const int len, loff_t pos)

static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)

{

	struct kvec kvec = {.iov_base = buf, .iov_len = len};

	struct iov_iter from;

	struct iov_iter i;

	ssize_t bw;



	iov_iter_kvec(&from, ITER_KVEC | WRITE, &kvec, 1, len);

	iov_iter_bvec(&i, ITER_BVEC, bvec, 1, bvec->bv_len);



	file_start_write(file);

	bw = vfs_iter_write(file, &from, &pos);

	bw = vfs_iter_write(file, &i, ppos);

	file_end_write(file);

	if (likely(bw == len))



	if (likely(bw ==  bvec->bv_len))

		return 0;

	printk_ratelimited(KERN_ERR "loop: Write error at byte offset %llu, length %i.\n",

			(unsigned long long)pos, len);



	printk_ratelimited(KERN_ERR

		"loop: Write error at byte offset %llu, length %i.\n",

		(unsigned long long)*ppos, bvec->bv_len);

	if (bw >= 0)

		bw = -EIO;

	return bw;

}



/**

 * do_lo_send_direct_write - helper for writing data to a loop device

 *

 * This is the fast, non-transforming version that does not need double

 * buffering.

 */

static int do_lo_send_direct_write(struct loop_device *lo,

		struct bio_vec *bvec, loff_t pos, struct page *page)

static int lo_write_simple(struct loop_device *lo, struct request *rq,

		loff_t pos)

{

	ssize_t bw = __do_lo_send_write(lo->lo_backing_file,

			kmap(bvec->bv_page) + bvec->bv_offset,

			bvec->bv_len, pos);

	kunmap(bvec->bv_page);

	struct bio_vec bvec;

	struct req_iterator iter;

	int ret = 0;



	rq_for_each_segment(bvec, rq, iter) {

		ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);

		if (ret < 0)

			break;

		cond_resched();

	return bw;

	}



/**

 * do_lo_send_write - helper for writing data to a loop device

 *

	return ret;

}



/*

 * This is the slow, transforming version that needs to double buffer the

 * data as it cannot do the transformations in place without having direct

 * access to the destination pages of the backing file.

 */

static int do_lo_send_write(struct loop_device *lo, struct bio_vec *bvec,

		loff_t pos, struct page *page)

{

	int ret = lo_do_transfer(lo, WRITE, page, 0, bvec->bv_page,

			bvec->bv_offset, bvec->bv_len, pos >> 9);

	if (likely(!ret))

		return __do_lo_send_write(lo->lo_backing_file,

				page_address(page), bvec->bv_len,

				pos);

	printk_ratelimited(KERN_ERR "loop: Transfer error at byte offset %llu, "

			"length %i.\n", (unsigned long long)pos, bvec->bv_len);

	if (ret > 0)

		ret = -EIO;

	return ret;

}



static int lo_send(struct loop_device *lo, struct request *rq, loff_t pos)

static int lo_write_transfer(struct loop_device *lo, struct request *rq,

		loff_t pos)

{

	int (*do_lo_send)(struct loop_device *, struct bio_vec *, loff_t,

			struct page *page);

	struct bio_vec bvec;

	struct bio_vec bvec, b;

	struct req_iterator iter;

	struct page *page = NULL;

	struct page *page;

	int ret = 0;



	if (lo->transfer != transfer_none) {

		page = alloc_page(GFP_NOIO | __GFP_HIGHMEM);

	page = alloc_page(GFP_NOIO);

	if (unlikely(!page))

			goto fail;

		kmap(page);

		do_lo_send = do_lo_send_write;

	} else {

		do_lo_send = do_lo_send_direct_write;

	}

		return -ENOMEM;



	rq_for_each_segment(bvec, rq, iter) {

		ret = do_lo_send(lo, &bvec, pos, page);

		ret = lo_do_transfer(lo, WRITE, page, 0, bvec.bv_page,

			bvec.bv_offset, bvec.bv_len, pos >> 9);

		if (unlikely(ret))

			break;



		b.bv_page = page;

		b.bv_offset = 0;

		b.bv_len = bvec.bv_len;

		ret = lo_write_bvec(lo->lo_backing_file, &b, &pos);

		if (ret < 0)

			break;

		pos += bvec.bv_len;

	}

	if (page) {

		kunmap(page);



	__free_page(page);

	}

out:

	return ret;

fail:

	printk_ratelimited(KERN_ERR "loop: Failed to allocate temporary page for write.\n");

	ret = -ENOMEM;

	goto out;

}



struct lo_read_data {

	struct loop_device *lo;

	struct page *page;

	unsigned offset;

	int bsize;

};



static int

lo_splice_actor(struct pipe_inode_info *pipe, struct pipe_buffer *buf,

		struct splice_desc *sd)

static int lo_read_simple(struct loop_device *lo, struct request *rq,

		loff_t pos)

{

	struct lo_read_data *p = sd->u.data;

	struct loop_device *lo = p->lo;

	struct page *page = buf->page;

	sector_t IV;

	int size;



	IV = ((sector_t) page->index << (PAGE_CACHE_SHIFT - 9)) +

							(buf->offset >> 9);

	size = sd->len;

	if (size > p->bsize)

		size = p->bsize;

	struct bio_vec bvec;

	struct req_iterator iter;

	struct iov_iter i;

	ssize_t len;



	if (lo_do_transfer(lo, READ, page, buf->offset, p->page, p->offset, size, IV)) {

		printk_ratelimited(KERN_ERR "loop: transfer error block %ld\n",

		       page->index);

		size = -EINVAL;

	}

	rq_for_each_segment(bvec, rq, iter) {

		iov_iter_bvec(&i, ITER_BVEC, &bvec, 1, bvec.bv_len);

		len = vfs_iter_read(lo->lo_backing_file, &i, &pos);

		if (len < 0)

			return len;



	flush_dcache_page(p->page);

		flush_dcache_page(bvec.bv_page);



	if (size > 0)

		p->offset += size;

		if (len != bvec.bv_len) {

			struct bio *bio;



	return size;

			__rq_for_each_bio(bio, rq)

				zero_fill_bio(bio);

			break;

		}

		cond_resched();

	}



static int

lo_direct_splice_actor(struct pipe_inode_info *pipe, struct splice_desc *sd)

{

	return __splice_from_pipe(pipe, sd, lo_splice_actor);

	return 0;

}



static ssize_t

do_lo_receive(struct loop_device *lo,

	      struct bio_vec *bvec, int bsize, loff_t pos)

static int lo_read_transfer(struct loop_device *lo, struct request *rq,

		loff_t pos)

{

	struct lo_read_data cookie;

	struct splice_desc sd;

	struct file *file;

	ssize_t retval;

	struct bio_vec bvec, b;

	struct req_iterator iter;

	struct iov_iter i;

	struct page *page;

	ssize_t len;

	int ret = 0;



	cookie.lo = lo;

	cookie.page = bvec->bv_page;

	cookie.offset = bvec->bv_offset;

	cookie.bsize = bsize;

	page = alloc_page(GFP_NOIO);

	if (unlikely(!page))

		return -ENOMEM;



	sd.len = 0;

	sd.total_len = bvec->bv_len;

	sd.flags = 0;

	sd.pos = pos;

	sd.u.data = &cookie;

	rq_for_each_segment(bvec, rq, iter) {

		loff_t offset = pos;



	file = lo->lo_backing_file;

	retval = splice_direct_to_actor(file, &sd, lo_direct_splice_actor);

		b.bv_page = page;

		b.bv_offset = 0;

		b.bv_len = bvec.bv_len;



	return retval;

		iov_iter_bvec(&i, ITER_BVEC, &b, 1, b.bv_len);

		len = vfs_iter_read(lo->lo_backing_file, &i, &pos);

		if (len < 0) {

			ret = len;

			goto out_free_page;

		}



static int

lo_receive(struct loop_device *lo, struct request *rq, int bsize, loff_t pos)

{

	struct bio_vec bvec;

	struct req_iterator iter;

	ssize_t s;

		ret = lo_do_transfer(lo, READ, page, 0, bvec.bv_page,

			bvec.bv_offset, len, offset >> 9);

		if (ret)

			goto out_free_page;



	rq_for_each_segment(bvec, rq, iter) {

		s = do_lo_receive(lo, &bvec, bsize, pos);

		if (s < 0)

			return s;

		flush_dcache_page(bvec.bv_page);



		if (s != bvec.bv_len) {

		if (len != bvec.bv_len) {

			struct bio *bio;



			__rq_for_each_bio(bio, rq)

				zero_fill_bio(bio);

			break;

		}

		pos += bvec.bv_len;

	}

	return 0;



	ret = 0;

out_free_page:

	__free_page(page);

	return ret;

}



static int lo_discard(struct loop_device *lo, struct request *rq, loff_t pos)
@@ -464,10 +403,17 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq) 
			ret = lo_req_flush(lo, rq);

		else if (rq->cmd_flags & REQ_DISCARD)

			ret = lo_discard(lo, rq, pos);

		else if (lo->transfer)

			ret = lo_write_transfer(lo, rq, pos);

		else

			ret = lo_send(lo, rq, pos);

	} else

		ret = lo_receive(lo, rq, lo->lo_blocksize, pos);

			ret = lo_write_simple(lo, rq, pos);



	} else {

		if (lo->transfer)

			ret = lo_read_transfer(lo, rq, pos);

		else

			ret = lo_read_simple(lo, rq, pos);

	}



	return ret;

}
@@ -788,7 +734,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode, 
	lo->lo_device = bdev;

	lo->lo_flags = lo_flags;

	lo->lo_backing_file = file;

	lo->transfer = transfer_none;

	lo->transfer = NULL;

	lo->ioctl = NULL;

	lo->lo_sizelimit = 0;

	lo->old_gfp_mask = mapping_gfp_mask(mapping);