zfs-builds-mm/zfs-2.0.0-rc6/include/sys/abd_impl.h
2020-11-15 11:35:49 +01:00

150 lines
4.4 KiB
C

/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2014 by Chunwei Chen. All rights reserved.
* Copyright (c) 2016, 2019 by Delphix. All rights reserved.
*/
#ifndef _ABD_IMPL_H
#define _ABD_IMPL_H
#include <sys/abd.h>
#ifdef __cplusplus
extern "C" {
#endif
typedef enum abd_flags {
ABD_FLAG_LINEAR = 1 << 0, /* is buffer linear (or scattered)? */
ABD_FLAG_OWNER = 1 << 1, /* does it own its data buffers? */
ABD_FLAG_META = 1 << 2, /* does this represent FS metadata? */
ABD_FLAG_MULTI_ZONE = 1 << 3, /* pages split over memory zones */
ABD_FLAG_MULTI_CHUNK = 1 << 4, /* pages split over multiple chunks */
ABD_FLAG_LINEAR_PAGE = 1 << 5, /* linear but allocd from page */
ABD_FLAG_GANG = 1 << 6, /* mult ABDs chained together */
ABD_FLAG_GANG_FREE = 1 << 7, /* gang ABD is responsible for mem */
ABD_FLAG_ZEROS = 1 << 8, /* ABD for zero-filled buffer */
} abd_flags_t;
typedef enum abd_stats_op {
ABDSTAT_INCR, /* Increase abdstat values */
ABDSTAT_DECR /* Decrease abdstat values */
} abd_stats_op_t;
struct abd {
abd_flags_t abd_flags;
uint_t abd_size; /* excludes scattered abd_offset */
list_node_t abd_gang_link;
struct abd *abd_parent;
zfs_refcount_t abd_children;
kmutex_t abd_mtx;
union {
struct abd_scatter {
uint_t abd_offset;
#if defined(__FreeBSD__) && defined(_KERNEL)
uint_t abd_chunk_size;
void *abd_chunks[];
#else
uint_t abd_nents;
struct scatterlist *abd_sgl;
#endif
} abd_scatter;
struct abd_linear {
void *abd_buf;
struct scatterlist *abd_sgl; /* for LINEAR_PAGE */
} abd_linear;
struct abd_gang {
list_t abd_gang_chain;
} abd_gang;
} abd_u;
};
struct scatterlist; /* forward declaration */
struct abd_iter {
/* public interface */
void *iter_mapaddr; /* addr corresponding to iter_pos */
size_t iter_mapsize; /* length of data valid at mapaddr */
/* private */
abd_t *iter_abd; /* ABD being iterated through */
size_t iter_pos;
size_t iter_offset; /* offset in current sg/abd_buf, */
/* abd_offset included */
struct scatterlist *iter_sg; /* current sg */
};
extern abd_t *abd_zero_scatter;
abd_t *abd_gang_get_offset(abd_t *, size_t *);
/*
* OS specific functions
*/
abd_t *abd_alloc_struct(size_t);
abd_t *abd_get_offset_scatter(abd_t *, size_t);
void abd_free_struct(abd_t *);
void abd_alloc_chunks(abd_t *, size_t);
void abd_free_chunks(abd_t *);
boolean_t abd_size_alloc_linear(size_t);
void abd_update_scatter_stats(abd_t *, abd_stats_op_t);
void abd_update_linear_stats(abd_t *, abd_stats_op_t);
void abd_verify_scatter(abd_t *);
void abd_free_linear_page(abd_t *);
/* OS specific abd_iter functions */
void abd_iter_init(struct abd_iter *, abd_t *);
boolean_t abd_iter_at_end(struct abd_iter *);
void abd_iter_advance(struct abd_iter *, size_t);
void abd_iter_map(struct abd_iter *);
void abd_iter_unmap(struct abd_iter *);
/*
* Helper macros
*/
#define ABDSTAT(stat) (abd_stats.stat.value.ui64)
#define ABDSTAT_INCR(stat, val) \
atomic_add_64(&abd_stats.stat.value.ui64, (val))
#define ABDSTAT_BUMP(stat) ABDSTAT_INCR(stat, 1)
#define ABDSTAT_BUMPDOWN(stat) ABDSTAT_INCR(stat, -1)
#define ABD_SCATTER(abd) (abd->abd_u.abd_scatter)
#define ABD_LINEAR_BUF(abd) (abd->abd_u.abd_linear.abd_buf)
#define ABD_GANG(abd) (abd->abd_u.abd_gang)
#if defined(_KERNEL)
#if defined(__FreeBSD__)
#define abd_enter_critical(flags) critical_enter()
#define abd_exit_critical(flags) critical_exit()
#else
#define abd_enter_critical(flags) local_irq_save(flags)
#define abd_exit_critical(flags) local_irq_restore(flags)
#endif
#else /* !_KERNEL */
#define abd_enter_critical(flags) ((void)0)
#define abd_exit_critical(flags) ((void)0)
#endif
#ifdef __cplusplus
}
#endif
#endif /* _ABD_IMPL_H */