mirror_zfs/include/sys/abd.h
Rob Norris 52a2af6fd1 abd: add page iterator
The regular ABD iterators yield data buffers, so they have to map and
unmap pages into kernel memory. If the caller only wants to count
chunks, or can use page pointers directly, then the map/unmap is just
unnecessary overhead.

This adds adb_iterate_page_func, which yields unmapped struct page
instead.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Closes #15533
Closes #15588
(cherry picked from commit 390b448726)
2024-03-28 13:29:46 -07:00

234 lines
6.2 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 https://opensource.org/licenses/CDDL-1.0.
* 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_H
#define _ABD_H
#include <sys/isa_defs.h>
#include <sys/debug.h>
#include <sys/zfs_refcount.h>
#include <sys/uio.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_FLAG_ALLOCD = 1 << 9, /* we allocated the abd_t */
} abd_flags_t;
typedef struct abd {
abd_flags_t abd_flags;
uint_t abd_size; /* excludes scattered abd_offset */
list_node_t abd_gang_link;
#ifdef ZFS_DEBUG
struct abd *abd_parent;
zfs_refcount_t abd_children;
#endif
kmutex_t abd_mtx;
union {
struct abd_scatter {
uint_t abd_offset;
#if defined(__FreeBSD__) && defined(_KERNEL)
void *abd_chunks[1]; /* actually variable-length */
#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;
} abd_t;
typedef int abd_iter_func_t(void *buf, size_t len, void *priv);
typedef int abd_iter_func2_t(void *bufa, void *bufb, size_t len, void *priv);
#if defined(__linux__) && defined(_KERNEL)
typedef int abd_iter_page_func_t(struct page *, size_t, size_t, void *);
#endif
extern int zfs_abd_scatter_enabled;
/*
* Allocations and deallocations
*/
__attribute__((malloc))
abd_t *abd_alloc(size_t, boolean_t);
__attribute__((malloc))
abd_t *abd_alloc_linear(size_t, boolean_t);
__attribute__((malloc))
abd_t *abd_alloc_gang(void);
__attribute__((malloc))
abd_t *abd_alloc_for_io(size_t, boolean_t);
__attribute__((malloc))
abd_t *abd_alloc_sametype(abd_t *, size_t);
boolean_t abd_size_alloc_linear(size_t);
void abd_gang_add(abd_t *, abd_t *, boolean_t);
void abd_free(abd_t *);
abd_t *abd_get_offset(abd_t *, size_t);
abd_t *abd_get_offset_size(abd_t *, size_t, size_t);
abd_t *abd_get_offset_struct(abd_t *, abd_t *, size_t, size_t);
abd_t *abd_get_zeros(size_t);
abd_t *abd_get_from_buf(void *, size_t);
void abd_cache_reap_now(void);
/*
* Conversion to and from a normal buffer
*/
void *abd_to_buf(abd_t *);
void *abd_borrow_buf(abd_t *, size_t);
void *abd_borrow_buf_copy(abd_t *, size_t);
void abd_return_buf(abd_t *, void *, size_t);
void abd_return_buf_copy(abd_t *, void *, size_t);
void abd_take_ownership_of_buf(abd_t *, boolean_t);
void abd_release_ownership_of_buf(abd_t *);
/*
* ABD operations
*/
int abd_iterate_func(abd_t *, size_t, size_t, abd_iter_func_t *, void *);
int abd_iterate_func2(abd_t *, abd_t *, size_t, size_t, size_t,
abd_iter_func2_t *, void *);
#if defined(__linux__) && defined(_KERNEL)
int abd_iterate_page_func(abd_t *, size_t, size_t, abd_iter_page_func_t *,
void *);
#endif
void abd_copy_off(abd_t *, abd_t *, size_t, size_t, size_t);
void abd_copy_from_buf_off(abd_t *, const void *, size_t, size_t);
void abd_copy_to_buf_off(void *, abd_t *, size_t, size_t);
int abd_cmp(abd_t *, abd_t *);
int abd_cmp_buf_off(abd_t *, const void *, size_t, size_t);
void abd_zero_off(abd_t *, size_t, size_t);
void abd_verify(abd_t *);
void abd_raidz_gen_iterate(abd_t **cabds, abd_t *dabd,
ssize_t csize, ssize_t dsize, const unsigned parity,
void (*func_raidz_gen)(void **, const void *, size_t, size_t));
void abd_raidz_rec_iterate(abd_t **cabds, abd_t **tabds,
ssize_t tsize, const unsigned parity,
void (*func_raidz_rec)(void **t, const size_t tsize, void **c,
const unsigned *mul),
const unsigned *mul);
/*
* Wrappers for calls with offsets of 0
*/
static inline void
abd_copy(abd_t *dabd, abd_t *sabd, size_t size)
{
abd_copy_off(dabd, sabd, 0, 0, size);
}
static inline void
abd_copy_from_buf(abd_t *abd, const void *buf, size_t size)
{
abd_copy_from_buf_off(abd, buf, 0, size);
}
static inline void
abd_copy_to_buf(void* buf, abd_t *abd, size_t size)
{
abd_copy_to_buf_off(buf, abd, 0, size);
}
static inline int
abd_cmp_buf(abd_t *abd, const void *buf, size_t size)
{
return (abd_cmp_buf_off(abd, buf, 0, size));
}
static inline void
abd_zero(abd_t *abd, size_t size)
{
abd_zero_off(abd, 0, size);
}
/*
* ABD type check functions
*/
static inline boolean_t
abd_is_linear(abd_t *abd)
{
return ((abd->abd_flags & ABD_FLAG_LINEAR) ? B_TRUE : B_FALSE);
}
static inline boolean_t
abd_is_linear_page(abd_t *abd)
{
return ((abd->abd_flags & ABD_FLAG_LINEAR_PAGE) ? B_TRUE : B_FALSE);
}
static inline boolean_t
abd_is_gang(abd_t *abd)
{
return ((abd->abd_flags & ABD_FLAG_GANG) ? B_TRUE : B_FALSE);
}
static inline uint_t
abd_get_size(abd_t *abd)
{
return (abd->abd_size);
}
/*
* Module lifecycle
* Defined in each specific OS's abd_os.c
*/
void abd_init(void);
void abd_fini(void);
/*
* Linux ABD bio functions
*/
#if defined(__linux__) && defined(_KERNEL)
unsigned int abd_bio_map_off(struct bio *, abd_t *, unsigned int, size_t);
unsigned long abd_nr_pages_off(abd_t *, unsigned int, size_t);
#endif
#ifdef __cplusplus
}
#endif
#endif /* _ABD_H */