/*
* 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) 2019 by Delphix. All rights reserved.
*/
/*
* ARC buffer data (ABD).
*
* ABDs are an abstract data structure for the ARC which can use two
* different ways of storing the underlying data:
*
* (a) Linear buffer. In this case, all the data in the ABD is stored in one
* contiguous buffer in memory (from a zio_[data_]buf_* kmem cache).
*
* +-------------------+
* | ABD (linear) |
* | abd_flags = ... |
* | abd_size = ... | +--------------------------------+
* | abd_buf ------------->| raw buffer of size abd_size |
* +-------------------+ +--------------------------------+
* no abd_chunks
*
* (b) Scattered buffer. In this case, the data in the ABD is split into
* equal-sized chunks (from the abd_chunk_cache kmem_cache), with pointers
* to the chunks recorded in an array at the end of the ABD structure.
*
* +-------------------+
* | ABD (scattered) |
* | abd_flags = ... |
* | abd_size = ... |
* | abd_offset = 0 | +-----------+
* | abd_chunks[0] ----------------------------->| chunk 0 |
* | abd_chunks[1] ---------------------+ +-----------+
* | ... | | +-----------+
* | abd_chunks[N-1] ---------+ +------->| chunk 1 |
* +-------------------+ | +-----------+
* | ...
* | +-----------+
* +----------------->| chunk N-1 |
* +-----------+
*
* In addition to directly allocating a linear or scattered ABD, it is also
* possible to create an ABD by requesting the "sub-ABD" starting at an offset
* within an existing ABD. In linear buffers this is simple (set abd_buf of
* the new ABD to the starting point within the original raw buffer), but
* scattered ABDs are a little more complex. The new ABD makes a copy of the
* relevant abd_chunks pointers (but not the underlying data). However, to
* provide arbitrary rather than only chunk-aligned starting offsets, it also
* tracks an abd_offset field which represents the starting point of the data
* within the first chunk in abd_chunks. For both linear and scattered ABDs,
* creating an offset ABD marks the original ABD as the offset's parent, and the
* original ABD's abd_children refcount is incremented. This data allows us to
* ensure the root ABD isn't deleted before its children.
*
* Most consumers should never need to know what type of ABD they're using --
* the ABD public API ensures that it's possible to transparently switch from
* using a linear ABD to a scattered one when doing so would be beneficial.
*
* If you need to use the data within an ABD directly, if you know it's linear
* (because you allocated it) you can use abd_to_buf() to access the underlying
* raw buffer. Otherwise, you should use one of the abd_borrow_buf* functions
* which will allocate a raw buffer if necessary. Use the abd_return_buf*
* functions to return any raw buffers that are no longer necessary when you're
* done using them.
*
* There are a variety of ABD APIs that implement basic buffer operations:
* compare, copy, read, write, and fill with zeroes. If you need a custom
* function which progressively accesses the whole ABD, use the abd_iterate_*
* functions.
*
* As an additional feature, linear and scatter ABD's can be stitched together
* by using the gang ABD type (abd_alloc_gang_abd()). This allows for
* multiple ABDs to be viewed as a singular ABD.
*
* It is possible to make all ABDs linear by setting zfs_abd_scatter_enabled to
* B_FALSE.
*/
#include <sys/abd_impl.h>
#include <sys/param.h>
#include <sys/zio.h>
#include <sys/zfs_context.h>
#include <sys/zfs_znode.h>
/* see block comment above for description */
int zfs_abd_scatter_enabled = B_TRUE;
boolean_t
abd_is_linear(abd_t *abd)
{
return ((abd->abd_flags & ABD_FLAG_LINEAR) != 0 ? B_TRUE : B_FALSE);
}
boolean_t
abd_is_linear_page(abd_t *abd)
{
return ((abd->abd_flags & ABD_FLAG_LINEAR_PAGE) != 0 ?
B_TRUE : B_FALSE);
}
boolean_t
abd_is_gang(abd_t *abd)
{
return ((abd->abd_flags & ABD_FLAG_GANG) != 0 ? B_TRUE :
B_FALSE);
}
void
abd_verify(abd_t *abd)
{
ASSERT3U(abd->abd_size, >, 0);
ASSERT3U(abd->abd_size, <=, SPA_MAXBLOCKSIZE);
ASSERT3U(abd->abd_flags, ==, abd->abd_flags & (ABD_FLAG_LINEAR |
ABD_FLAG_OWNER | ABD_FLAG_META | ABD_FLAG_MULTI_ZONE |
ABD_FLAG_MULTI_CHUNK | ABD_FLAG_LINEAR_PAGE | ABD_FLAG_GANG |
ABD_FLAG_GANG_FREE | ABD_FLAG_ZEROS));
IMPLY(abd->abd_parent != NULL, !(abd->abd_flags & ABD_FLAG_OWNER));
IMPLY(abd->abd_flags & ABD_FLAG_META, abd->abd_flags & ABD_FLAG_OWNER);
if (abd_is_linear(abd)) {
ASSERT3P(ABD_LINEAR_BUF(abd), !=, NULL);
} else if (abd_is_gang(abd)) {
uint_t child_sizes = 0;
for (abd_t *cabd = list_head(&ABD_GANG(abd).abd_gang_chain);
cabd != NULL;
cabd = list_next(&ABD_GANG(abd).abd_gang_chain, cabd)) {
ASSERT(list_link_active(&cabd->abd_gang_link));
child_sizes += cabd->abd_size;
abd_verify(cabd);
}
ASSERT3U(abd->abd_size, ==, child_sizes);
} else {
abd_verify_scatter(abd);
}
}
uint_t
abd_get_size(abd_t *abd)
{
abd_verify(abd);
return (abd->abd_size);
}
/*
* Allocate an ABD, along with its own underlying data buffers. Use this if you
* don't care whether the ABD is linear or not.
*/
abd_t *
abd_alloc(size_t size, boolean_t is_metadata)
{
if (!zfs_abd_scatter_enabled || abd_size_alloc_linear(size))
return (abd_alloc_linear(size, is_metadata));
VERIFY3U(size, <=, SPA_MAXBLOCKSIZE);
abd_t *abd = abd_alloc_struct(size);
abd->abd_flags = ABD_FLAG_OWNER;
abd->abd_u.abd_scatter.abd_offset = 0;
abd_alloc_chunks(abd, size);
if (is_metadata) {
abd->abd_flags |= ABD_FLAG_META;
}
abd->abd_size = size;
abd->abd_parent = NULL;
zfs_refcount_create(&abd->abd_children);
abd_update_scatter_stats(abd, ABDSTAT_INCR);
return (abd);
}
static void
abd_free_scatter(abd_t *abd)
{
abd_free_chunks(abd);
zfs_refcount_destroy(&abd->abd_children);
abd_update_scatter_stats(abd, ABDSTAT_DECR);
abd_free_struct(abd);
}
static void
abd_put_gang_abd(abd_t *abd)
{
ASSERT(abd_is_gang(abd));
abd_t *cabd;
while ((cabd = list_remove_head(&ABD_GANG(abd).abd_gang_chain))
!= NULL) {
ASSERT0(cabd->abd_flags & ABD_FLAG_GANG_FREE);
abd->abd_size -= cabd->abd_size;
abd_put(cabd);
}
ASSERT0(abd->abd_size);
list_destroy(&ABD_GANG(abd).abd_gang_chain);
}
/*
* Free an ABD allocated from abd_get_offset() or abd_get_from_buf(). Will not
* free the underlying scatterlist or buffer.
*/
void
abd_put(abd_t *abd)
{
if (abd == NULL)
return;
abd_verify(abd);
ASSERT(!(abd->abd_flags & ABD_FLAG_OWNER));
if (abd->abd_parent != NULL) {
(void) zfs_refcount_remove_many(&abd->abd_parent->abd_children,
abd->abd_size, abd);
}
if (abd_is_gang(abd))
abd_put_gang_abd(abd);
zfs_refcount_destroy(&abd->abd_children);
abd_free_struct(abd);
}
/*
* Allocate an ABD that must be linear, along with its own underlying data
* buffer. Only use this when it would be very annoying to write your ABD
* consumer with a scattered ABD.
*/
abd_t *
abd_alloc_linear(size_t size, boolean_t is_metadata)
{
abd_t *abd = abd_alloc_struct(0);
VERIFY3U(size, <=, SPA_MAXBLOCKSIZE);
abd->abd_flags = ABD_FLAG_LINEAR | ABD_FLAG_OWNER;
if (is_metadata) {
abd->abd_flags |= ABD_FLAG_META;
}
abd->abd_size = size;
abd->abd_parent = NULL;
zfs_refcount_create(&abd->abd_children);
if (is_metadata) {
ABD_LINEAR_BUF(abd) = zio_buf_alloc(size);
} else {
ABD_LINEAR_BUF(abd) = zio_data_buf_alloc(size);
}
abd_update_linear_stats(abd, ABDSTAT_INCR);
return (abd);
}
static void
abd_free_linear(abd_t *abd)
{
if (abd_is_linear_page(abd)) {
abd_free_linear_page(abd);
return;
}
if (abd->abd_flags & ABD_FLAG_META) {
zio_buf_free(ABD_LINEAR_BUF(abd), abd->abd_size);
} else {
zio_data_buf_free(ABD_LINEAR_BUF(abd), abd->abd_size);
}
zfs_refcount_destroy(&abd->abd_children);
abd_update_linear_stats(abd, ABDSTAT_DECR);
abd_free_struct(abd);
}
static void
abd_free_gang_abd(abd_t *abd)
{
ASSERT(abd_is_gang(abd));
abd_t *cabd = list_head(&ABD_GANG(abd).abd_gang_chain);
while (cabd != NULL) {
/*
* We must acquire the child ABDs mutex to ensure that if it
* is being added to another gang ABD we will set the link
* as inactive when removing it from this gang ABD and before
* adding it to the other gang ABD.
*/
mutex_enter(&cabd->abd_mtx);
ASSERT(list_link_active(&cabd->abd_gang_link));
list_remove(&ABD_GANG(abd).abd_gang_chain, cabd);
mutex_exit(&cabd->abd_mtx);
abd->abd_size -= cabd->abd_size;
if (cabd->abd_flags & ABD_FLAG_GANG_FREE) {
if (cabd->abd_flags & ABD_FLAG_OWNER)
abd_free(cabd);
else
abd_put(cabd);
}
cabd = list_head(&ABD_GANG(abd).abd_gang_chain);
}
ASSERT0(abd->abd_size);
list_destroy(&ABD_GANG(abd).abd_gang_chain);
zfs_refcount_destroy(&abd->abd_children);
abd_free_struct(abd);
}
/*
* Free an ABD. Only use this on ABDs allocated with abd_alloc(),
* abd_alloc_linear(), or abd_alloc_gang_abd().
*/
void
abd_free(abd_t *abd)
{
if (abd == NULL)
return;
abd_verify(abd);
ASSERT3P(abd->abd_parent, ==, NULL);
ASSERT(abd->abd_flags & ABD_FLAG_OWNER);
if (abd_is_linear(abd))
abd_free_linear(abd);
else if (abd_is_gang(abd))
abd_free_gang_abd(abd);
else
abd_free_scatter(abd);
}
/*
* Allocate an ABD of the same format (same metadata flag, same scatterize
* setting) as another ABD.
*/
abd_t *
abd_alloc_sametype(abd_t *sabd, size_t size)
{
boolean_t is_metadata = (sabd->abd_flags & ABD_FLAG_META) != 0;
if (abd_is_linear(sabd) &&
!abd_is_linear_page(sabd)) {
return (abd_alloc_linear(size, is_metadata));
} else {
return (abd_alloc(size, is_metadata));
}
}
/*
* Create gang ABD that will be the head of a list of ABD's. This is used
* to "chain" scatter/gather lists together when constructing aggregated
* IO's. To free this abd, abd_free() must be called.
*/
abd_t *
abd_alloc_gang_abd(void)
{
abd_t *abd;
abd = abd_alloc_struct(0);
abd->abd_flags = ABD_FLAG_GANG | ABD_FLAG_OWNER;
abd->abd_size = 0;
abd->abd_parent = NULL;
list_create(&ABD_GANG(abd).abd_gang_chain,
sizeof (abd_t), offsetof(abd_t, abd_gang_link));
zfs_refcount_create(&abd->abd_children);
return (abd);
}
/*
* Add a child gang ABD to a parent gang ABDs chained list.
*/
static void
abd_gang_add_gang(abd_t *pabd, abd_t *cabd, boolean_t free_on_free)
{
ASSERT(abd_is_gang(pabd));
ASSERT(abd_is_gang(cabd));
if (free_on_free) {
/*
* If the parent is responsible for freeing the child gang
* ABD we will just splice the childs children ABD list to
* the parents list and immediately free the child gang ABD
* struct. The parent gang ABDs children from the child gang
* will retain all the free_on_free settings after being
* added to the parents list.
*/
pabd->abd_size += cabd->abd_size;
list_move_tail(&ABD_GANG(pabd).abd_gang_chain,
&ABD_GANG(cabd).abd_gang_chain);
ASSERT(list_is_empty(&ABD_GANG(cabd).abd_gang_chain));
abd_verify(pabd);
abd_free_struct(cabd);
} else {
for (abd_t *child = list_head(&ABD_GANG(cabd).abd_gang_chain);
child != NULL;
child = list_next(&ABD_GANG(cabd).abd_gang_chain, child)) {
/*
* We always pass B_FALSE for free_on_free as it is the
* original child gang ABDs responsibilty to determine
* if any of its child ABDs should be free'd on the call
* to abd_free().
*/
abd_gang_add(pabd, child, B_FALSE);
}
abd_verify(pabd);
}
}
/*
* Add a child ABD to a gang ABD's chained list.
*/
void
abd_gang_add(abd_t *pabd, abd_t *cabd, boolean_t free_on_free)
{
ASSERT(abd_is_gang(pabd));
abd_t *child_abd = NULL;
/*
* If the child being added is a gang ABD, we will add the
* childs ABDs to the parent gang ABD. This alllows us to account
* for the offset correctly in the parent gang ABD.
*/
if (abd_is_gang(cabd)) {
ASSERT(!list_link_active(&cabd->abd_gang_link));
ASSERT(!list_is_empty(&ABD_GANG(cabd).abd_gang_chain));
return (abd_gang_add_gang(pabd, cabd, free_on_free));
}
ASSERT(!abd_is_gang(cabd));
/*
* In order to verify that an ABD is not already part of
* another gang ABD, we must lock the child ABD's abd_mtx
* to check its abd_gang_link status. We unlock the abd_mtx
* only after it is has been added to a gang ABD, which
* will update the abd_gang_link's status. See comment below
* for how an ABD can be in multiple gang ABD's simultaneously.
*/
mutex_enter(&cabd->abd_mtx);
if (list_link_active(&cabd->abd_gang_link)) {
/*
* If the child ABD is already part of another
* gang ABD then we must allocate a new
* ABD to use a separate link. We mark the newly
* allocated ABD with ABD_FLAG_GANG_FREE, before
* adding it to the gang ABD's list, to make the
* gang ABD aware that it is responsible to call
* abd_put(). We use abd_get_offset() in order
* to just allocate a new ABD but avoid copying the
* data over into the newly allocated ABD.
*
* An ABD may become part of multiple gang ABD's. For
* example, when writing ditto bocks, the same ABD
* is used to write 2 or 3 locations with 2 or 3
* zio_t's. Each of the zio's may be aggregated with
* different adjacent zio's. zio aggregation uses gang
* zio's, so the single ABD can become part of multiple
* gang zio's.
*
* The ASSERT below is to make sure that if
* free_on_free is passed as B_TRUE, the ABD can
* not be in multiple gang ABD's. The gang ABD
* can not be responsible for cleaning up the child
* ABD memory allocation if the ABD can be in
* multiple gang ABD's at one time.
*/
ASSERT3B(free_on_free, ==, B_FALSE);
child_abd = abd_get_offset(cabd, 0);
child_abd->abd_flags |= ABD_FLAG_GANG_FREE;
} else {
child_abd = cabd;
if (free_on_free)
child_abd->abd_flags |= ABD_FLAG_GANG_FREE;
}
ASSERT3P(child_abd, !=, NULL);
list_insert_tail(&ABD_GANG(pabd).abd_gang_chain, child_abd);
mutex_exit(&cabd->abd_mtx);
pabd->abd_size += child_abd->abd_size;
}
/*
* Locate the ABD for the supplied offset in the gang ABD.
* Return a new offset relative to the returned ABD.
*/
abd_t *
abd_gang_get_offset(abd_t *abd, size_t *off)
{
abd_t *cabd;
ASSERT(abd_is_gang(abd));
ASSERT3U(*off, <, abd->abd_size);
for (cabd = list_head(&ABD_GANG(abd).abd_gang_chain); cabd != NULL;
cabd = list_next(&ABD_GANG(abd).abd_gang_chain, cabd)) {
if (*off >= cabd->abd_size)
*off -= cabd->abd_size;
else
return (cabd);
}
VERIFY3P(cabd, !=, NULL);
return (cabd);
}
/*
* Allocate a new ABD to point to offset off of sabd. It shares the underlying
* buffer data with sabd. Use abd_put() to free. sabd must not be freed while
* any derived ABDs exist.
*/
static abd_t *
abd_get_offset_impl(abd_t *sabd, size_t off, size_t size)
{
abd_t *abd = NULL;
abd_verify(sabd);
ASSERT3U(off, <=, sabd->abd_size);
if (abd_is_linear(sabd)) {
abd = abd_alloc_struct(0);
/*
* Even if this buf is filesystem metadata, we only track that
* if we own the underlying data buffer, which is not true in
* this case. Therefore, we don't ever use ABD_FLAG_META here.
*/
abd->abd_flags = ABD_FLAG_LINEAR;
ABD_LINEAR_BUF(abd) = (char *)ABD_LINEAR_BUF(sabd) + off;
} else if (abd_is_gang(sabd)) {
size_t left = size;
abd = abd_alloc_gang_abd();
abd->abd_flags &= ~ABD_FLAG_OWNER;
for (abd_t *cabd = abd_gang_get_offset(sabd, &off);
cabd != NULL && left > 0;
cabd = list_next(&ABD_GANG(sabd).abd_gang_chain, cabd)) {
int csize = MIN(left, cabd->abd_size - off);
abd_t *nabd = abd_get_offset_impl(cabd, off, csize);
abd_gang_add(abd, nabd, B_FALSE);
left -= csize;
off = 0;
}
ASSERT3U(left, ==, 0);
} else {
abd = abd_get_offset_scatter(sabd, off);
}
abd->abd_size = size;
abd->abd_parent = sabd;
zfs_refcount_create(&abd->abd_children);
(void) zfs_refcount_add_many(&sabd->abd_children, abd->abd_size, abd);
return (abd);
}
abd_t *
abd_get_offset(abd_t *sabd, size_t off)
{
size_t size = sabd->abd_size > off ? sabd->abd_size - off : 0;
VERIFY3U(size, >, 0);
return (abd_get_offset_impl(sabd, off, size));
}
abd_t *
abd_get_offset_size(abd_t *sabd, size_t off, size_t size)
{
ASSERT3U(off + size, <=, sabd->abd_size);
return (abd_get_offset_impl(sabd, off, size));
}
/*
* Return a size scatter ABD. In order to free the returned
* ABD abd_put() must be called.
*/
abd_t *
abd_get_zeros(size_t size)
{
ASSERT3P(abd_zero_scatter, !=, NULL);
ASSERT3U(size, <=, SPA_MAXBLOCKSIZE);
return (abd_get_offset_size(abd_zero_scatter, 0, size));
}
/*
* Allocate a linear ABD structure for buf. You must free this with abd_put()
* since the resulting ABD doesn't own its own buffer.
*/
abd_t *
abd_get_from_buf(void *buf, size_t size)
{
abd_t *abd = abd_alloc_struct(0);
VERIFY3U(size, <=, SPA_MAXBLOCKSIZE);
/*
* Even if this buf is filesystem metadata, we only track that if we
* own the underlying data buffer, which is not true in this case.
* Therefore, we don't ever use ABD_FLAG_META here.
*/
abd->abd_flags = ABD_FLAG_LINEAR;
abd->abd_size = size;
abd->abd_parent = NULL;
zfs_refcount_create(&abd->abd_children);
ABD_LINEAR_BUF(abd) = buf;
return (abd);
}
/*
* Get the raw buffer associated with a linear ABD.
*/
void *
abd_to_buf(abd_t *abd)
{
ASSERT(abd_is_linear(abd));
abd_verify(abd);
return (ABD_LINEAR_BUF(abd));
}
/*
* Borrow a raw buffer from an ABD without copying the contents of the ABD
* into the buffer. If the ABD is scattered, this will allocate a raw buffer
* whose contents are undefined. To copy over the existing data in the ABD, use
* abd_borrow_buf_copy() instead.
*/
void *
abd_borrow_buf(abd_t *abd, size_t n)
{
void *buf;
abd_verify(abd);
ASSERT3U(abd->abd_size, >=, n);
if (abd_is_linear(abd)) {
buf = abd_to_buf(abd);
} else {
buf = zio_buf_alloc(n);
}
(void) zfs_refcount_add_many(&abd->abd_children, n, buf);
return (buf);
}
void *
abd_borrow_buf_copy(abd_t *abd, size_t n)
{
void *buf = abd_borrow_buf(abd, n);
if (!abd_is_linear(abd)) {
abd_copy_to_buf(buf, abd, n);
}
return (buf);
}
/*
* Return a borrowed raw buffer to an ABD. If the ABD is scattered, this will
* not change the contents of the ABD and will ASSERT that you didn't modify
* the buffer since it was borrowed. If you want any changes you made to buf to
* be copied back to abd, use abd_return_buf_copy() instead.
*/
void
abd_return_buf(abd_t *abd, void *buf, size_t n)
{
abd_verify(abd);
ASSERT3U(abd->abd_size, >=, n);
if (abd_is_linear(abd)) {
ASSERT3P(buf, ==, abd_to_buf(abd));
} else {
ASSERT0(abd_cmp_buf(abd, buf, n));
zio_buf_free(buf, n);
}
(void) zfs_refcount_remove_many(&abd->abd_children, n, buf);
}
void
abd_return_buf_copy(abd_t *abd, void *buf, size_t n)
{
if (!abd_is_linear(abd)) {
abd_copy_from_buf(abd, buf, n);
}
abd_return_buf(abd, buf, n);
}
void
abd_release_ownership_of_buf(abd_t *abd)
{
ASSERT(abd_is_linear(abd));
ASSERT(abd->abd_flags & ABD_FLAG_OWNER);
/*
* abd_free() needs to handle LINEAR_PAGE ABD's specially.
* Since that flag does not survive the
* abd_release_ownership_of_buf() -> abd_get_from_buf() ->
* abd_take_ownership_of_buf() sequence, we don't allow releasing
* these "linear but not zio_[data_]buf_alloc()'ed" ABD's.
*/
ASSERT(!abd_is_linear_page(abd));
abd_verify(abd);
abd->abd_flags &= ~ABD_FLAG_OWNER;
/* Disable this flag since we no longer own the data buffer */
abd->abd_flags &= ~ABD_FLAG_META;
abd_update_linear_stats(abd, ABDSTAT_DECR);
}
/*
* Give this ABD ownership of the buffer that it's storing. Can only be used on
* linear ABDs which were allocated via abd_get_from_buf(), or ones allocated
* with abd_alloc_linear() which subsequently released ownership of their buf
* with abd_release_ownership_of_buf().
*/
void
abd_take_ownership_of_buf(abd_t *abd, boolean_t is_metadata)
{
ASSERT(abd_is_linear(abd));
ASSERT(!(abd->abd_flags & ABD_FLAG_OWNER));
abd_verify(abd);
abd->abd_flags |= ABD_FLAG_OWNER;
if (is_metadata) {
abd->abd_flags |= ABD_FLAG_META;
}
abd_update_linear_stats(abd, ABDSTAT_INCR);
}
/*
* Initializes an abd_iter based on whether the abd is a gang ABD
* or just a single ABD.
*/
static inline abd_t *
abd_init_abd_iter(abd_t *abd, struct abd_iter *aiter, size_t off)
{
abd_t *cabd = NULL;
if (abd_is_gang(abd)) {
cabd = abd_gang_get_offset(abd, &off);
if (cabd) {
abd_iter_init(aiter, cabd);
abd_iter_advance(aiter, off);
}
} else {
abd_iter_init(aiter, abd);
abd_iter_advance(aiter, off);
}
return (cabd);
}
/*
* Advances an abd_iter. We have to be careful with gang ABD as
* advancing could mean that we are at the end of a particular ABD and
* must grab the ABD in the gang ABD's list.
*/
static inline abd_t *
abd_advance_abd_iter(abd_t *abd, abd_t *cabd, struct abd_iter *aiter,
size_t len)
{
abd_iter_advance(aiter, len);
if (abd_is_gang(abd) && abd_iter_at_end(aiter)) {
ASSERT3P(cabd, !=, NULL);
cabd = list_next(&ABD_GANG(abd).abd_gang_chain, cabd);
if (cabd) {
abd_iter_init(aiter, cabd);
abd_iter_advance(aiter, 0);
}
}
return (cabd);
}
int
abd_iterate_func(abd_t *abd, size_t off, size_t size,
abd_iter_func_t *func, void *private)
{
int ret = 0;
struct abd_iter aiter;
boolean_t abd_multi;
abd_t *c_abd;
abd_verify(abd);
ASSERT3U(off + size, <=, abd->abd_size);
abd_multi = abd_is_gang(abd);
c_abd = abd_init_abd_iter(abd, &aiter, off);
while (size > 0) {
/* If we are at the end of the gang ABD we are done */
if (abd_multi && !c_abd)
break;
abd_iter_map(&aiter);
size_t len = MIN(aiter.iter_mapsize, size);
ASSERT3U(len, >, 0);
ret = func(aiter.iter_mapaddr, len, private);
abd_iter_unmap(&aiter);
if (ret != 0)
break;
size -= len;
c_abd = abd_advance_abd_iter(abd, c_abd, &aiter, len);
}
return (ret);
}
struct buf_arg {
void *arg_buf;
};
static int
abd_copy_to_buf_off_cb(void *buf, size_t size, void *private)
{
struct buf_arg *ba_ptr = private;
(void) memcpy(ba_ptr->arg_buf, buf, size);
ba_ptr->arg_buf = (char *)ba_ptr->arg_buf + size;
return (0);
}
/*
* Copy abd to buf. (off is the offset in abd.)
*/
void
abd_copy_to_buf_off(void *buf, abd_t *abd, size_t off, size_t size)
{
struct buf_arg ba_ptr = { buf };
(void) abd_iterate_func(abd, off, size, abd_copy_to_buf_off_cb,
&ba_ptr);
}
static int
abd_cmp_buf_off_cb(void *buf, size_t size, void *private)
{
int ret;
struct buf_arg *ba_ptr = private;
ret = memcmp(buf, ba_ptr->arg_buf, size);
ba_ptr->arg_buf = (char *)ba_ptr->arg_buf + size;
return (ret);
}
/*
* Compare the contents of abd to buf. (off is the offset in abd.)
*/
int
abd_cmp_buf_off(abd_t *abd, const void *buf, size_t off, size_t size)
{
struct buf_arg ba_ptr = { (void *) buf };
return (abd_iterate_func(abd, off, size, abd_cmp_buf_off_cb, &ba_ptr));
}
static int
abd_copy_from_buf_off_cb(void *buf, size_t size, void *private)
{
struct buf_arg *ba_ptr = private;
(void) memcpy(buf, ba_ptr->arg_buf, size);
ba_ptr->arg_buf = (char *)ba_ptr->arg_buf + size;
return (0);
}
/*
* Copy from buf to abd. (off is the offset in abd.)
*/
void
abd_copy_from_buf_off(abd_t *abd, const void *buf, size_t off, size_t size)
{
struct buf_arg ba_ptr = { (void *) buf };
(void) abd_iterate_func(abd, off, size, abd_copy_from_buf_off_cb,
&ba_ptr);
}
/*ARGSUSED*/
static int
abd_zero_off_cb(void *buf, size_t size, void *private)
{
(void) memset(buf, 0, size);
return (0);
}
/*
* Zero out the abd from a particular offset to the end.
*/
void
abd_zero_off(abd_t *abd, size_t off, size_t size)
{
(void) abd_iterate_func(abd, off, size, abd_zero_off_cb, NULL);
}
/*
* Iterate over two ABDs and call func incrementally on the two ABDs' data in
* equal-sized chunks (passed to func as raw buffers). func could be called many
* times during this iteration.
*/
int
abd_iterate_func2(abd_t *dabd, abd_t *sabd, size_t doff, size_t soff,
size_t size, abd_iter_func2_t *func, void *private)
{
int ret = 0;
struct abd_iter daiter, saiter;
boolean_t dabd_is_gang_abd, sabd_is_gang_abd;
abd_t *c_dabd, *c_sabd;
abd_verify(dabd);
abd_verify(sabd);
ASSERT3U(doff + size, <=, dabd->abd_size);
ASSERT3U(soff + size, <=, sabd->abd_size);
dabd_is_gang_abd = abd_is_gang(dabd);
sabd_is_gang_abd = abd_is_gang(sabd);
c_dabd = abd_init_abd_iter(dabd, &daiter, doff);
c_sabd = abd_init_abd_iter(sabd, &saiter, soff);
while (size > 0) {
/* if we are at the end of the gang ABD we are done */
if ((dabd_is_gang_abd && !c_dabd) ||
(sabd_is_gang_abd && !c_sabd))
break;
abd_iter_map(&daiter);
abd_iter_map(&saiter);
size_t dlen = MIN(daiter.iter_mapsize, size);
size_t slen = MIN(saiter.iter_mapsize, size);
size_t len = MIN(dlen, slen);
ASSERT(dlen > 0 || slen > 0);
ret = func(daiter.iter_mapaddr, saiter.iter_mapaddr, len,
private);
abd_iter_unmap(&saiter);
abd_iter_unmap(&daiter);
if (ret != 0)
break;
size -= len;
c_dabd =
abd_advance_abd_iter(dabd, c_dabd, &daiter, len);
c_sabd =
abd_advance_abd_iter(sabd, c_sabd, &saiter, len);
}
return (ret);
}
/*ARGSUSED*/
static int
abd_copy_off_cb(void *dbuf, void *sbuf, size_t size, void *private)
{
(void) memcpy(dbuf, sbuf, size);
return (0);
}
/*
* Copy from sabd to dabd starting from soff and doff.
*/
void
abd_copy_off(abd_t *dabd, abd_t *sabd, size_t doff, size_t soff, size_t size)
{
(void) abd_iterate_func2(dabd, sabd, doff, soff, size,
abd_copy_off_cb, NULL);
}
/*ARGSUSED*/
static int
abd_cmp_cb(void *bufa, void *bufb, size_t size, void *private)
{
return (memcmp(bufa, bufb, size));
}
/*
* Compares the contents of two ABDs.
*/
int
abd_cmp(abd_t *dabd, abd_t *sabd)
{
ASSERT3U(dabd->abd_size, ==, sabd->abd_size);
return (abd_iterate_func2(dabd, sabd, 0, 0, dabd->abd_size,
abd_cmp_cb, NULL));
}
/*
* Iterate over code ABDs and a data ABD and call @func_raidz_gen.
*
* @cabds parity ABDs, must have equal size
* @dabd data ABD. Can be NULL (in this case @dsize = 0)
* @func_raidz_gen should be implemented so that its behaviour
* is the same when taking linear and when taking scatter
*/
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))
{
int i;
ssize_t len, dlen;
struct abd_iter caiters[3];
struct abd_iter daiter = {0};
void *caddrs[3];
unsigned long flags __maybe_unused = 0;
abd_t *c_cabds[3];
abd_t *c_dabd = NULL;
boolean_t cabds_is_gang_abd[3];
boolean_t dabd_is_gang_abd = B_FALSE;
ASSERT3U(parity, <=, 3);
for (i = 0; i < parity; i++) {
cabds_is_gang_abd[i] = abd_is_gang(cabds[i]);
c_cabds[i] = abd_init_abd_iter(cabds[i], &caiters[i], 0);
}
if (dabd) {
dabd_is_gang_abd = abd_is_gang(dabd);
c_dabd = abd_init_abd_iter(dabd, &daiter, 0);
}
ASSERT3S(dsize, >=, 0);
abd_enter_critical(flags);
while (csize > 0) {
/* if we are at the end of the gang ABD we are done */
if (dabd_is_gang_abd && !c_dabd)
break;
for (i = 0; i < parity; i++) {
/*
* If we are at the end of the gang ABD we are
* done.
*/
if (cabds_is_gang_abd[i] && !c_cabds[i])
break;
abd_iter_map(&caiters[i]);
caddrs[i] = caiters[i].iter_mapaddr;
}
len = csize;
if (dabd && dsize > 0)
abd_iter_map(&daiter);
switch (parity) {
case 3:
len = MIN(caiters[2].iter_mapsize, len);
/* falls through */
case 2:
len = MIN(caiters[1].iter_mapsize, len);
/* falls through */
case 1:
len = MIN(caiters[0].iter_mapsize, len);
}
/* must be progressive */
ASSERT3S(len, >, 0);
if (dabd && dsize > 0) {
/* this needs precise iter.length */
len = MIN(daiter.iter_mapsize, len);
dlen = len;
} else
dlen = 0;
/* must be progressive */
ASSERT3S(len, >, 0);
/*
* The iterated function likely will not do well if each
* segment except the last one is not multiple of 512 (raidz).
*/
ASSERT3U(((uint64_t)len & 511ULL), ==, 0);
func_raidz_gen(caddrs, daiter.iter_mapaddr, len, dlen);
for (i = parity-1; i >= 0; i--) {
abd_iter_unmap(&caiters[i]);
c_cabds[i] =
abd_advance_abd_iter(cabds[i], c_cabds[i],
&caiters[i], len);
}
if (dabd && dsize > 0) {
abd_iter_unmap(&daiter);
c_dabd =
abd_advance_abd_iter(dabd, c_dabd, &daiter,
dlen);
dsize -= dlen;
}
csize -= len;
ASSERT3S(dsize, >=, 0);
ASSERT3S(csize, >=, 0);
}
abd_exit_critical(flags);
}
/*
* Iterate over code ABDs and data reconstruction target ABDs and call
* @func_raidz_rec. Function maps at most 6 pages atomically.
*
* @cabds parity ABDs, must have equal size
* @tabds rec target ABDs, at most 3
* @tsize size of data target columns
* @func_raidz_rec expects syndrome data in target columns. Function
* reconstructs data and overwrites target columns.
*/
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)
{
int i;
ssize_t len;
struct abd_iter citers[3];
struct abd_iter xiters[3];
void *caddrs[3], *xaddrs[3];
unsigned long flags __maybe_unused = 0;
boolean_t cabds_is_gang_abd[3];
boolean_t tabds_is_gang_abd[3];
abd_t *c_cabds[3];
abd_t *c_tabds[3];
ASSERT3U(parity, <=, 3);
for (i = 0; i < parity; i++) {
cabds_is_gang_abd[i] = abd_is_gang(cabds[i]);
tabds_is_gang_abd[i] = abd_is_gang(tabds[i]);
c_cabds[i] =
abd_init_abd_iter(cabds[i], &citers[i], 0);
c_tabds[i] =
abd_init_abd_iter(tabds[i], &xiters[i], 0);
}
abd_enter_critical(flags);
while (tsize > 0) {
for (i = 0; i < parity; i++) {
/*
* If we are at the end of the gang ABD we
* are done.
*/
if (cabds_is_gang_abd[i] && !c_cabds[i])
break;
if (tabds_is_gang_abd[i] && !c_tabds[i])
break;
abd_iter_map(&citers[i]);
abd_iter_map(&xiters[i]);
caddrs[i] = citers[i].iter_mapaddr;
xaddrs[i] = xiters[i].iter_mapaddr;
}
len = tsize;
switch (parity) {
case 3:
len = MIN(xiters[2].iter_mapsize, len);
len = MIN(citers[2].iter_mapsize, len);
/* falls through */
case 2:
len = MIN(xiters[1].iter_mapsize, len);
len = MIN(citers[1].iter_mapsize, len);
/* falls through */
case 1:
len = MIN(xiters[0].iter_mapsize, len);
len = MIN(citers[0].iter_mapsize, len);
}
/* must be progressive */
ASSERT3S(len, >, 0);
/*
* The iterated function likely will not do well if each
* segment except the last one is not multiple of 512 (raidz).
*/
ASSERT3U(((uint64_t)len & 511ULL), ==, 0);
func_raidz_rec(xaddrs, len, caddrs, mul);
for (i = parity-1; i >= 0; i--) {
abd_iter_unmap(&xiters[i]);
abd_iter_unmap(&citers[i]);
c_tabds[i] =
abd_advance_abd_iter(tabds[i], c_tabds[i],
&xiters[i], len);
c_cabds[i] =
abd_advance_abd_iter(cabds[i], c_cabds[i],
&citers[i], len);
}
tsize -= len;
ASSERT3S(tsize, >=, 0);
}
abd_exit_critical(flags);
}