[mirror_ubuntu-jammy-kernel.git] / 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>
#include <linux/errno.h>
#include <linux/mm.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 */
};

struct bvec_iter_all {
	struct bio_vec	bv;
	int		idx;
	unsigned	done;
};

/*
 * 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])

/* multi-page (mp_bvec) helpers */
#define mp_bvec_iter_page(bvec, iter)				\
	(__bvec_iter_bvec((bvec), (iter))->bv_page)

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

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

#define mp_bvec_iter_page_idx(bvec, iter)			\
	(mp_bvec_iter_offset((bvec), (iter)) / PAGE_SIZE)

#define mp_bvec_iter_bvec(bvec, iter)				\
((struct bio_vec) {						\
	.bv_page	= mp_bvec_iter_page((bvec), (iter)),	\
	.bv_len		= mp_bvec_iter_len((bvec), (iter)),	\
	.bv_offset	= mp_bvec_iter_offset((bvec), (iter)),	\
})

/* For building single-page bvec in flight */
 #define bvec_iter_offset(bvec, iter)				\
	(mp_bvec_iter_offset((bvec), (iter)) % PAGE_SIZE)

#define bvec_iter_len(bvec, iter)				\
	min_t(unsigned, mp_bvec_iter_len((bvec), (iter)),		\
	      PAGE_SIZE - bvec_iter_offset((bvec), (iter)))

#define bvec_iter_page(bvec, iter)				\
	nth_page(mp_bvec_iter_page((bvec), (iter)),		\
		 mp_bvec_iter_page_idx((bvec), (iter)))

#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 bool bvec_iter_advance(const struct bio_vec *bv,
		struct bvec_iter *iter, unsigned bytes)
{
	if (WARN_ONCE(bytes > iter->bi_size,
		     "Attempted to advance past end of bvec iter\n")) {
		iter->bi_size = 0;
		return false;
	}

	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++;
		}
	}
	return true;
}

#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))

/* for iterating one bio from start to end */
#define BVEC_ITER_ALL_INIT (struct bvec_iter)				\
{									\
	.bi_sector	= 0,						\
	.bi_size	= UINT_MAX,					\
	.bi_idx		= 0,						\
	.bi_bvec_done	= 0,						\
}

static inline struct bio_vec *bvec_init_iter_all(struct bvec_iter_all *iter_all)
{
	iter_all->bv.bv_page = NULL;
	iter_all->done = 0;

	return &iter_all->bv;
}

static inline void mp_bvec_next_segment(const struct bio_vec *bvec,
					struct bvec_iter_all *iter_all)
{
	struct bio_vec *bv = &iter_all->bv;

	if (bv->bv_page) {
		bv->bv_page = nth_page(bv->bv_page, 1);
		bv->bv_offset = 0;
	} else {
		bv->bv_page = bvec->bv_page;
		bv->bv_offset = bvec->bv_offset;
	}
	bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset,
			   bvec->bv_len - iter_all->done);
}

/*
 * Get the last single-page segment from the multi-page bvec and store it
 * in @seg
 */
static inline void mp_bvec_last_segment(const struct bio_vec *bvec,
					struct bio_vec *seg)
{
	unsigned total = bvec->bv_offset + bvec->bv_len;
	unsigned last_page = (total - 1) / PAGE_SIZE;

	seg->bv_page = nth_page(bvec->bv_page, last_page);

	/* the whole segment is inside the last page */
	if (bvec->bv_offset >= last_page * PAGE_SIZE) {
		seg->bv_offset = bvec->bv_offset % PAGE_SIZE;
		seg->bv_len = bvec->bv_len;
	} else {
		seg->bv_offset = 0;
		seg->bv_len = total - last_page * PAGE_SIZE;
	}
}

#endif /* __LINUX_BVEC_ITER_H */
Commit	Line	Data
8fc55455 ML	1	/*
	2	* bvec iterator
	3	*
	4	* Copyright (C) 2001 Ming Lei <ming.lei@canonical.com>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	*
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public Licens
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
	19	*/
	20	#ifndef __LINUX_BVEC_ITER_H
	21	#define __LINUX_BVEC_ITER_H
	22
0781e79e ML	23	#include <linux/kernel.h>
0781e79e ML	24	#include <linux/bug.h>
b1fb2c52	25	#include <linux/errno.h>
3d75ca0a	26	#include <linux/mm.h>
0781e79e ML	27
	28	/*
	29	* was unsigned short, but we might as well be ready for > 64kB I/O pages
	30	*/
	31	struct bio_vec {
	32	struct page *bv_page;
	33	unsigned int bv_len;
	34	unsigned int bv_offset;
	35	};
	36
	37	struct bvec_iter {
	38	sector_t bi_sector; /* device address in 512 byte
	39	sectors */
	40	unsigned int bi_size; /* residual I/O count */
	41
	42	unsigned int bi_idx; /* current index into bvl_vec */
	43
	44	unsigned int bi_bvec_done; /* number of bytes completed in
	45	current bvec */
	46	};
8fc55455	47
6dc4f100 ML	48	struct bvec_iter_all {
	49	struct bio_vec bv;
	50	int idx;
	51	unsigned done;
	52	};
	53
8fc55455 ML	54	/*
	55	* various member access, note that bio_data should of course not be used
	56	* on highmem page vectors
	57	*/
	58	#define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx])
	59
3d75ca0a ML	60	/* multi-page (mp_bvec) helpers */
3d75ca0a ML	61	#define mp_bvec_iter_page(bvec, iter) \
8fc55455 ML	62	(__bvec_iter_bvec((bvec), (iter))->bv_page)
8fc55455 ML	63
3d75ca0a	64	#define mp_bvec_iter_len(bvec, iter) \
8fc55455 ML	65	min((iter).bi_size, \
	66	__bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
	67
3d75ca0a	68	#define mp_bvec_iter_offset(bvec, iter) \
8fc55455 ML	69	(__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
8fc55455 ML	70
3d75ca0a ML	71	#define mp_bvec_iter_page_idx(bvec, iter) \
	72	(mp_bvec_iter_offset((bvec), (iter)) / PAGE_SIZE)
	73
	74	#define mp_bvec_iter_bvec(bvec, iter) \
	75	((struct bio_vec) { \
	76	.bv_page = mp_bvec_iter_page((bvec), (iter)), \
	77	.bv_len = mp_bvec_iter_len((bvec), (iter)), \
	78	.bv_offset = mp_bvec_iter_offset((bvec), (iter)), \
	79	})
	80
	81	/* For building single-page bvec in flight */
	82	#define bvec_iter_offset(bvec, iter) \
	83	(mp_bvec_iter_offset((bvec), (iter)) % PAGE_SIZE)
	84
	85	#define bvec_iter_len(bvec, iter) \
	86	min_t(unsigned, mp_bvec_iter_len((bvec), (iter)), \
	87	PAGE_SIZE - bvec_iter_offset((bvec), (iter)))
	88
	89	#define bvec_iter_page(bvec, iter) \
	90	nth_page(mp_bvec_iter_page((bvec), (iter)), \
	91	mp_bvec_iter_page_idx((bvec), (iter)))
	92
8fc55455 ML	93	#define bvec_iter_bvec(bvec, iter) \
	94	((struct bio_vec) { \
	95	.bv_page = bvec_iter_page((bvec), (iter)), \
	96	.bv_len = bvec_iter_len((bvec), (iter)), \
	97	.bv_offset = bvec_iter_offset((bvec), (iter)), \
	98	})
	99
b1fb2c52 DM	100	static inline bool bvec_iter_advance(const struct bio_vec *bv,
b1fb2c52 DM	101	struct bvec_iter *iter, unsigned bytes)
8fc55455	102	{
b1fb2c52 DM	103	if (WARN_ONCE(bytes > iter->bi_size,
	104	"Attempted to advance past end of bvec iter\n")) {
	105	iter->bi_size = 0;
	106	return false;
	107	}
8fc55455 ML	108
8fc55455 ML	109	while (bytes) {
1ea049b2 JB	110	unsigned iter_len = bvec_iter_len(bv, *iter);
1ea049b2 JB	111	unsigned len = min(bytes, iter_len);
8fc55455 ML	112
	113	bytes -= len;
	114	iter->bi_size -= len;
	115	iter->bi_bvec_done += len;
	116
	117	if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
	118	iter->bi_bvec_done = 0;
	119	iter->bi_idx++;
	120	}
	121	}
b1fb2c52	122	return true;
8fc55455 ML	123	}
	124
	125	#define for_each_bvec(bvl, bio_vec, iter, start) \
	126	for (iter = (start); \
	127	(iter).bi_size && \
	128	((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
	129	bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
	130
3c892a09 ML	131	/* for iterating one bio from start to end */
	132	#define BVEC_ITER_ALL_INIT (struct bvec_iter) \
	133	{ \
	134	.bi_sector = 0, \
	135	.bi_size = UINT_MAX, \
	136	.bi_idx = 0, \
	137	.bi_bvec_done = 0, \
	138	}
	139
6dc4f100 ML	140	static inline struct bio_vec bvec_init_iter_all(struct bvec_iter_all iter_all)
	141	{
	142	iter_all->bv.bv_page = NULL;
	143	iter_all->done = 0;
	144
	145	return &iter_all->bv;
	146	}
	147
	148	static inline void mp_bvec_next_segment(const struct bio_vec *bvec,
	149	struct bvec_iter_all *iter_all)
	150	{
	151	struct bio_vec *bv = &iter_all->bv;
	152
	153	if (bv->bv_page) {
	154	bv->bv_page = nth_page(bv->bv_page, 1);
	155	bv->bv_offset = 0;
	156	} else {
	157	bv->bv_page = bvec->bv_page;
	158	bv->bv_offset = bvec->bv_offset;
	159	}
	160	bv->bv_len = min_t(unsigned int, PAGE_SIZE - bv->bv_offset,
	161	bvec->bv_len - iter_all->done);
	162	}
	163
45a3fb95 ML	164	/*
	165	* Get the last single-page segment from the multi-page bvec and store it
	166	* in @seg
	167	*/
	168	static inline void mp_bvec_last_segment(const struct bio_vec *bvec,
	169	struct bio_vec *seg)
	170	{
	171	unsigned total = bvec->bv_offset + bvec->bv_len;
	172	unsigned last_page = (total - 1) / PAGE_SIZE;
	173
	174	seg->bv_page = nth_page(bvec->bv_page, last_page);
	175
	176	/* the whole segment is inside the last page */
	177	if (bvec->bv_offset >= last_page * PAGE_SIZE) {
	178	seg->bv_offset = bvec->bv_offset % PAGE_SIZE;
	179	seg->bv_len = bvec->bv_len;
	180	} else {
	181	seg->bv_offset = 0;
	182	seg->bv_len = total - last_page * PAGE_SIZE;
	183	}
	184	}
	185
8fc55455	186	#endif /* __LINUX_BVEC_ITER_H */