Release 4.12 include/linux/bvec.h

/*
 * bvec iterator
 *
 * Copyright (C) 2001 Ming Lei <ming.lei@canonical.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public Licens
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
 */
#ifndef __LINUX_BVEC_ITER_H

#define __LINUX_BVEC_ITER_H

#include <linux/kernel.h>
#include <linux/bug.h>

/*
 * was unsigned short, but we might as well be ready for > 64kB I/O pages
 */

struct bio_vec {
	
struct page	*bv_page;
	
unsigned int	bv_len;
	
unsigned int	bv_offset;
};


struct bvec_iter {
	
sector_t		bi_sector;	/* device address in 512 byte
                                                   sectors */
	
unsigned int		bi_size;	/* residual I/O count */

	
unsigned int		bi_idx;		/* current index into bvl_vec */

	
unsigned int            bi_bvec_done;	/* number of bytes completed in
                                                   current bvec */
};

/*
 * various member access, note that bio_data should of course not be used
 * on highmem page vectors
 */

#define __bvec_iter_bvec(bvec, iter)	(&(bvec)[(iter).bi_idx])


#define bvec_iter_page(bvec, iter)				\
	(__bvec_iter_bvec((bvec), (iter))->bv_page)


#define bvec_iter_len(bvec, iter)				\
	min((iter).bi_size,                                     \
            __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)


#define bvec_iter_offset(bvec, iter)				\
	(__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)


#define bvec_iter_bvec(bvec, iter)				\
((struct bio_vec) {                                             \
        .bv_page        = bvec_iter_page((bvec), (iter)),       \
        .bv_len         = bvec_iter_len((bvec), (iter)),        \
        .bv_offset      = bvec_iter_offset((bvec), (iter)),     \
})



static inline void bvec_iter_advance(const struct bio_vec *bv,
				     struct bvec_iter *iter,
				     unsigned bytes)
{
	WARN_ONCE(bytes > iter->bi_size,
		  "Attempted to advance past end of bvec iter\n");

	while (bytes) {
		unsigned iter_len = bvec_iter_len(bv, *iter);
		unsigned len = min(bytes, iter_len);

		bytes -= len;
		iter->bi_size -= len;
		iter->bi_bvec_done += len;

		if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
			iter->bi_bvec_done = 0;
			iter->bi_idx++;
		}
	}
}

Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
94
90.38%
2
66.67%
Johannes Berg
10
9.62%
1
33.33%
Total
104
100.00%
3
100.00%


#define for_each_bvec(bvl, bio_vec, iter, start)			\
	for (iter = (start);                                            \
             (iter).bi_size &&                                          \
                ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
             bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))

#endif /* __LINUX_BVEC_ITER_H */
Overall Contributors
Person
Tokens
Prop
Commits
CommitProp
Ming Lei
217
95.59%
3
75.00%
Johannes Berg
10
4.41%
1
25.00%
Total
227
100.00%
4
100.00%
Directory: include/linux

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