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Differential D18893 Diff 53221 sys/kern/subr_rangeset.c

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sys/kern/subr_rangeset.c

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2019 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Konstantin Belousov <kib@FreeBSD.org>
* under sponsorship from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/pctrie.h>
#include <sys/rangeset.h>
#include <vm/uma.h>
#ifdef DIAGNOSTIC
static void rangeset_check(struct rangeset *rs);
#else
#define rangeset_check(rs)
#endif
static uma_zone_t rs_node_zone;
static void
markjUnsubmitted
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Style: missing newline.

markj: Style: missing newline.
rs_rangeset_init(void *arg __unused)
{
rs_node_zone = uma_zcreate("rangeset pctrie nodes",
pctrie_node_size(), NULL, NULL, pctrie_zone_init, NULL,
UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
}
markjUnsubmitted
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Why _NOFREE?

markj: Why _NOFREE?
SYSINIT(rs, SI_SUB_LOCK, SI_ORDER_ANY, rs_rangeset_init, NULL);
static void *
rs_node_alloc(struct pctrie *ptree)
{
struct rangeset *rs;
rs = __containerof(ptree, struct rangeset, rs_trie);
return (uma_zalloc(rs_node_zone, rs->rs_alloc_flags));
}
static void
rs_node_free(struct pctrie *ptree __unused, void *node)
{
uma_zfree(rs_node_zone, node);
}
void
rangeset_init(struct rangeset *rs, rs_dup_data_t dup_data,
rs_free_data_t free_data, void *data_ctx, u_int alloc_flags)
{
pctrie_init(&rs->rs_trie);
rs->rs_dup_data = dup_data;
rs->rs_free_data = free_data;
rs->rs_data_ctx = data_ctx;
rs->rs_alloc_flags = alloc_flags;
}
void
rangeset_fini(struct rangeset *rs)
{
rangeset_check(rs);
rangeset_remove_all(rs);
}
bool
rangeset_check_empty(struct rangeset *rs, uint64_t start, uint64_t end)
{
struct rs_el *r;
uint64_t *r1;
rangeset_check(rs);
r1 = pctrie_lookup_le(&rs->rs_trie, end);
if (r1 != NULL) {
r = __containerof(r1, struct rs_el, re_start);
if (r->re_end > start)
return (false);
}
return (true);
}
int
rangeset_insert(struct rangeset *rs, uint64_t start, uint64_t end,
void *data)
{
struct rs_el *r;
int error;
rangeset_check(rs);
error = rangeset_remove(rs, start, end);
if (error != 0)
return (error);
r = data;
r->re_start = start;
r->re_end = end;
error = pctrie_insert(&rs->rs_trie, &r->re_start, rs_node_alloc);
rangeset_check(rs);
return (error);
}
int
rangeset_remove_pred(struct rangeset *rs, uint64_t start, uint64_t end,
rs_pred_t pred)
{
struct rs_el *r, *rn;
uint64_t *r1;
int error;
rangeset_check(rs);
error = 0;
for (; end > 0 && start < end;) {
r1 = pctrie_lookup_le(&rs->rs_trie, end - 1);
if (r1 == NULL)
break;
r = __containerof(r1, struct rs_el, re_start);
/*
* ------============================--|-------|----
* rs re s e
*/
if (r->re_end <= start)
break;
if (r->re_end <= end) {
if (r->re_start < start) {
/*
* ------========|==============-------|----
* rs s re e
*/
if (pred(rs->rs_data_ctx, r))
r->re_end = start;
break;
}
/*
* ------|--------===================----------|----
* s rs re e
*/
end = r->re_start;
if (pred(rs->rs_data_ctx, r)) {
pctrie_remove(&rs->rs_trie, r->re_start,
rs_node_free);
rs->rs_free_data(rs->rs_data_ctx, r);
}
continue;
}
/*
* ------|--------====================|==========----
* s rs e re
*/
if (r->re_start >= start) {
if (pred(rs->rs_data_ctx, r)) {
pctrie_remove(&rs->rs_trie, r->re_start,
rs_node_free);
r->re_start = end;
error = pctrie_insert(&rs->rs_trie,
&r->re_start, rs_node_alloc);
/*
* The insert above must succeed
* because rs_node zone is marked
* nofree and we freed one element
* just before.
*/
MPASS(error == 0);
} else {
end = r->re_start;
}
continue;
}
/*
* ------=========|===================|==========----
* rs s e re
*/
if (pred(rs->rs_data_ctx, r)) {
/*
* Split. Can only happen once, and then if
* any allocation fails, the rangeset is kept
* intact.
*/
rn = rs->rs_dup_data(rs->rs_data_ctx, r);
if (rn == NULL) {
error = ENOMEM;
break;
}
rn->re_start = end;
rn->re_end = r->re_end;
error = pctrie_insert(&rs->rs_trie, &rn->re_start,
rs_node_alloc);
if (error != 0) {
rs->rs_free_data(rs->rs_data_ctx, rn);
break;
}
r->re_end = start;
}
break;
}
rangeset_check(rs);
return (error);
}
static bool
rangeset_true_pred(void *ctx __unused, void *r __unused)
{
return (true);
}
int
rangeset_remove(struct rangeset *rs, uint64_t start, uint64_t end)
{
return (rangeset_remove_pred(rs, start, end, rangeset_true_pred));
}
void
rangeset_remove_all(struct rangeset *rs)
{
struct rs_el *r;
uint64_t *r1;
for (;;) {
r1 = pctrie_lookup_ge(&rs->rs_trie, 0);
if (r1 == NULL)
break;
r = __containerof(r1, struct rs_el, re_start);
pctrie_remove(&rs->rs_trie, r->re_start, rs_node_free);
rs->rs_free_data(rs->rs_data_ctx, r);
}
}
void *
rangeset_get(struct rangeset *rs, uint64_t place)
{
markjUnsubmitted
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I would call this rangeset_lookup(). To me at least, _get() implies that the range is known to be present, i.e., the lookup cannot fail. Same with pmap_pkru_get().

markj: I would call this rangeset_lookup(). To me at least, _get() implies that the range is known to…
struct rs_el *r;
uint64_t *r1;
rangeset_check(rs);
r1 = pctrie_lookup_le(&rs->rs_trie, place);
if (r1 == NULL)
return (NULL);
r = __containerof(r1, struct rs_el, re_start);
if (r->re_end <= place)
return (NULL);
return (r);
}
int
rangeset_copy(struct rangeset *dst_rs, struct rangeset *src_rs)
{
struct rs_el *src_r, *dst_r;
uint64_t cursor, *r1;
int error;
MPASS(pctrie_is_empty(&dst_rs->rs_trie));
rangeset_check(src_rs);
markjUnsubmitted
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I believe this will fail if an earlier attempt returned ENOMEM and we did a partial copy.

markj: I believe this will fail if an earlier attempt returned ENOMEM and we did a partial copy.
kibAuthorUnsubmitted
Done
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FIxed by removing everything on copy failure.

kib: FIxed by removing everything on copy failure.
MPASS(dst_rs->rs_dup_data == src_rs->rs_dup_data);
error = 0;
for (cursor = 0;; cursor = src_r->re_start + 1) {
r1 = pctrie_lookup_ge(&src_rs->rs_trie, cursor);
if (r1 == NULL)
break;
src_r = __containerof(r1, struct rs_el, re_start);
dst_r = dst_rs->rs_dup_data(dst_rs->rs_data_ctx, src_r);
if (dst_r == NULL) {
error = ENOMEM;
break;
}
error = pctrie_insert(&dst_rs->rs_trie, &dst_r->re_start,
rs_node_alloc);
if (error != 0)
break;
}
if (error != 0)
rangeset_remove_all(dst_rs);
return (error);
}
#ifdef DIAGNOSTIC
static void
rangeset_check(struct rangeset *rs)
{
struct rs_el *r, *rp;
uint64_t cursor, *r1;
for (cursor = 0, rp = NULL;; cursor = r->re_start + 1, rp = r) {
r1 = pctrie_lookup_ge(&rs->rs_trie, cursor);
if (r1 == NULL)
break;
r = __containerof(r1, struct rs_el, re_start);
KASSERT(r->re_start < r->re_end,
("invalid interval rs %p elem %p (%#jx, %#jx)",
rs, r, (uintmax_t)r->re_start, (uintmax_t)r->re_end));
if (rp != NULL) {
KASSERT(rp->re_end <= r->re_start,
("non-ascending neighbors rs %p "
"prev elem %p (%#jx, %#jx) elem %p (%#jx, %#jx)",
rs, rp, (uintmax_t)rp->re_start,
(uintmax_t)rp->re_end, r, (uintmax_t)r->re_start,
(uintmax_t)r->re_end));
}
}
}
#endif
#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>
#include <ddb/ddb.h>
DB_SHOW_COMMAND(rangeset, rangeset_show_fn)
{
struct rangeset *rs;
struct rs_el *r;
uint64_t cursor, *r1;
if (!have_addr) {
db_printf("show rangeset addr\n");
return;
}
rs = (struct rangeset *)addr;
db_printf("rangeset %p\n", rs);
for (cursor = 0;; cursor = r->re_start + 1) {
r1 = pctrie_lookup_ge(&rs->rs_trie, cursor);
if (r1 == NULL)
break;
r = __containerof(r1, struct rs_el, re_start);
db_printf(" el %p start %#jx end %#jx\n",
r, r->re_start, r->re_end);
}
}
#endif