| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20100227163636.GA10646@elte.hu>
Date: Sat, 27 Feb 2010 17:36:36 +0100
From: Ingo Molnar <mingo@...e.hu>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>,
"Pallipadi, Venkatesh" <venkatesh.pallipadi@...el.com>
Subject: [RFC GIT PULL] x86/pat changes for v2.6.34
Linus,
Please pull the latest x86-pat-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git x86-pat-for-linus
Please have a look at the lib/rbtree.c changes. The rebalancing changes ought
to not impact performance - rb_erase() possibly in a small way. Should this
perhaps be done via a separate API entry, instead of modifying existing rbtree
code?
out-of-topic modifications in x86-pat-for-linus:
------------------------------------------------
include/linux/rbtree.h # 17d9ddc: rbtree: Add support for augmented
lib/rbtree.c # 17d9ddc: rbtree: Add support for augmented
Thanks,
Ingo
------------------>
Pallipadi, Venkatesh (2):
rbtree: Add support for augmented rbtrees
x86, pat: Migrate to rbtree only backend for pat memtype management
venkatesh.pallipadi@...el.com (1):
x86, pat: Preparatory changes in pat.c for bigger rbtree change
Documentation/rbtree.txt | 58 ++++++++++
arch/x86/mm/Makefile | 1 +
arch/x86/mm/pat.c | 231 +++----------------------------------
arch/x86/mm/pat_internal.h | 46 ++++++++
arch/x86/mm/pat_rbtree.c | 271 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/rbtree.h | 5 +-
lib/rbtree.c | 48 +++++++-
7 files changed, 443 insertions(+), 217 deletions(-)
create mode 100644 arch/x86/mm/pat_internal.h
create mode 100644 arch/x86/mm/pat_rbtree.c
diff --git a/Documentation/rbtree.txt b/Documentation/rbtree.txt
index aae8355..221f38b 100644
--- a/Documentation/rbtree.txt
+++ b/Documentation/rbtree.txt
@@ -190,3 +190,61 @@ Example:
for (node = rb_first(&mytree); node; node = rb_next(node))
printk("key=%s\n", rb_entry(node, struct mytype, node)->keystring);
+Support for Augmented rbtrees
+-----------------------------
+
+Augmented rbtree is an rbtree with "some" additional data stored in each node.
+This data can be used to augment some new functionality to rbtree.
+Augmented rbtree is an optional feature built on top of basic rbtree
+infrastructure. rbtree user who wants this feature will have an augment
+callback function in rb_root initialized.
+
+This callback function will be called from rbtree core routines whenever
+a node has a change in one or both of its children. It is the responsibility
+of the callback function to recalculate the additional data that is in the
+rb node using new children information. Note that if this new additional
+data affects the parent node's additional data, then callback function has
+to handle it and do the recursive updates.
+
+
+Interval tree is an example of augmented rb tree. Reference -
+"Introduction to Algorithms" by Cormen, Leiserson, Rivest and Stein.
+More details about interval trees:
+
+Classical rbtree has a single key and it cannot be directly used to store
+interval ranges like [lo:hi] and do a quick lookup for any overlap with a new
+lo:hi or to find whether there is an exact match for a new lo:hi.
+
+However, rbtree can be augmented to store such interval ranges in a structured
+way making it possible to do efficient lookup and exact match.
+
+This "extra information" stored in each node is the maximum hi
+(max_hi) value among all the nodes that are its descendents. This
+information can be maintained at each node just be looking at the node
+and its immediate children. And this will be used in O(log n) lookup
+for lowest match (lowest start address among all possible matches)
+with something like:
+
+find_lowest_match(lo, hi, node)
+{
+ lowest_match = NULL;
+ while (node) {
+ if (max_hi(node->left) > lo) {
+ // Lowest overlap if any must be on left side
+ node = node->left;
+ } else if (overlap(lo, hi, node)) {
+ lowest_match = node;
+ break;
+ } else if (lo > node->lo) {
+ // Lowest overlap if any must be on right side
+ node = node->right;
+ } else {
+ break;
+ }
+ }
+ return lowest_match;
+}
+
+Finding exact match will be to first find lowest match and then to follow
+successor nodes looking for exact match, until the start of a node is beyond
+the hi value we are looking for.
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 06630d2..a4c7683 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile
@@ -6,6 +6,7 @@ nostackp := $(call cc-option, -fno-stack-protector)
CFLAGS_physaddr.o := $(nostackp)
CFLAGS_setup_nx.o := $(nostackp)
+obj-$(CONFIG_X86_PAT) += pat_rbtree.o
obj-$(CONFIG_SMP) += tlb.o
obj-$(CONFIG_X86_32) += pgtable_32.o iomap_32.o
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index ae9648e..9510111 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -30,6 +30,8 @@
#include <asm/pat.h>
#include <asm/io.h>
+#include "pat_internal.h"
+
#ifdef CONFIG_X86_PAT
int __read_mostly pat_enabled = 1;
@@ -53,19 +55,15 @@ static inline void pat_disable(const char *reason)
#endif
-static int debug_enable;
+int pat_debug_enable;
static int __init pat_debug_setup(char *str)
{
- debug_enable = 1;
+ pat_debug_enable = 1;
return 0;
}
__setup("debugpat", pat_debug_setup);
-#define dprintk(fmt, arg...) \
- do { if (debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)
-
-
static u64 __read_mostly boot_pat_state;
enum {
@@ -132,84 +130,7 @@ void pat_init(void)
#undef PAT
-static char *cattr_name(unsigned long flags)
-{
- switch (flags & _PAGE_CACHE_MASK) {
- case _PAGE_CACHE_UC: return "uncached";
- case _PAGE_CACHE_UC_MINUS: return "uncached-minus";
- case _PAGE_CACHE_WB: return "write-back";
- case _PAGE_CACHE_WC: return "write-combining";
- default: return "broken";
- }
-}
-
-/*
- * The global memtype list keeps track of memory type for specific
- * physical memory areas. Conflicting memory types in different
- * mappings can cause CPU cache corruption. To avoid this we keep track.
- *
- * The list is sorted based on starting address and can contain multiple
- * entries for each address (this allows reference counting for overlapping
- * areas). All the aliases have the same cache attributes of course.
- * Zero attributes are represented as holes.
- *
- * The data structure is a list that is also organized as an rbtree
- * sorted on the start address of memtype range.
- *
- * memtype_lock protects both the linear list and rbtree.
- */
-
-struct memtype {
- u64 start;
- u64 end;
- unsigned long type;
- struct list_head nd;
- struct rb_node rb;
-};
-
-static struct rb_root memtype_rbroot = RB_ROOT;
-static LIST_HEAD(memtype_list);
-static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */
-
-static struct memtype *memtype_rb_search(struct rb_root *root, u64 start)
-{
- struct rb_node *node = root->rb_node;
- struct memtype *last_lower = NULL;
-
- while (node) {
- struct memtype *data = container_of(node, struct memtype, rb);
-
- if (data->start < start) {
- last_lower = data;
- node = node->rb_right;
- } else if (data->start > start) {
- node = node->rb_left;
- } else
- return data;
- }
-
- /* Will return NULL if there is no entry with its start <= start */
- return last_lower;
-}
-
-static void memtype_rb_insert(struct rb_root *root, struct memtype *data)
-{
- struct rb_node **new = &(root->rb_node);
- struct rb_node *parent = NULL;
-
- while (*new) {
- struct memtype *this = container_of(*new, struct memtype, rb);
-
- parent = *new;
- if (data->start <= this->start)
- new = &((*new)->rb_left);
- else if (data->start > this->start)
- new = &((*new)->rb_right);
- }
-
- rb_link_node(&data->rb, parent, new);
- rb_insert_color(&data->rb, root);
-}
+static DEFINE_SPINLOCK(memtype_lock); /* protects memtype accesses */
/*
* Does intersection of PAT memory type and MTRR memory type and returns
@@ -237,33 +158,6 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type)
return req_type;
}
-static int
-chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type)
-{
- if (new->type != entry->type) {
- if (type) {
- new->type = entry->type;
- *type = entry->type;
- } else
- goto conflict;
- }
-
- /* check overlaps with more than one entry in the list */
- list_for_each_entry_continue(entry, &memtype_list, nd) {
- if (new->end <= entry->start)
- break;
- else if (new->type != entry->type)
- goto conflict;
- }
- return 0;
-
- conflict:
- printk(KERN_INFO "%s:%d conflicting memory types "
- "%Lx-%Lx %s<->%s\n", current->comm, current->pid, new->start,
- new->end, cattr_name(new->type), cattr_name(entry->type));
- return -EBUSY;
-}
-
static int pat_pagerange_is_ram(unsigned long start, unsigned long end)
{
int ram_page = 0, not_rampage = 0;
@@ -364,9 +258,8 @@ static int free_ram_pages_type(u64 start, u64 end)
int reserve_memtype(u64 start, u64 end, unsigned long req_type,
unsigned long *new_type)
{
- struct memtype *new, *entry;
+ struct memtype *new;
unsigned long actual_type;
- struct list_head *where;
int is_range_ram;
int err = 0;
@@ -423,42 +316,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
spin_lock(&memtype_lock);
- /* Search for existing mapping that overlaps the current range */
- where = NULL;
- list_for_each_entry(entry, &memtype_list, nd) {
- if (end <= entry->start) {
- where = entry->nd.prev;
- break;
- } else if (start <= entry->start) { /* end > entry->start */
- err = chk_conflict(new, entry, new_type);
- if (!err) {
- dprintk("Overlap at 0x%Lx-0x%Lx\n",
- entry->start, entry->end);
- where = entry->nd.prev;
- }
- break;
- } else if (start < entry->end) { /* start > entry->start */
- err = chk_conflict(new, entry, new_type);
- if (!err) {
- dprintk("Overlap at 0x%Lx-0x%Lx\n",
- entry->start, entry->end);
-
- /*
- * Move to right position in the linked
- * list to add this new entry
- */
- list_for_each_entry_continue(entry,
- &memtype_list, nd) {
- if (start <= entry->start) {
- where = entry->nd.prev;
- break;
- }
- }
- }
- break;
- }
- }
-
+ err = rbt_memtype_check_insert(new, new_type);
if (err) {
printk(KERN_INFO "reserve_memtype failed 0x%Lx-0x%Lx, "
"track %s, req %s\n",
@@ -469,13 +327,6 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
return err;
}
- if (where)
- list_add(&new->nd, where);
- else
- list_add_tail(&new->nd, &memtype_list);
-
- memtype_rb_insert(&memtype_rbroot, new);
-
spin_unlock(&memtype_lock);
dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
@@ -487,7 +338,6 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type,
int free_memtype(u64 start, u64 end)
{
- struct memtype *entry, *saved_entry;
int err = -EINVAL;
int is_range_ram;
@@ -511,46 +361,7 @@ int free_memtype(u64 start, u64 end)
}
spin_lock(&memtype_lock);
-
- entry = memtype_rb_search(&memtype_rbroot, start);
- if (unlikely(entry == NULL))
- goto unlock_ret;
-
- /*
- * Saved entry points to an entry with start same or less than what
- * we searched for. Now go through the list in both directions to look
- * for the entry that matches with both start and end, with list stored
- * in sorted start address
- */
- saved_entry = entry;
- list_for_each_entry_from(entry, &memtype_list, nd) {
- if (entry->start == start && entry->end == end) {
- rb_erase(&entry->rb, &memtype_rbroot);
- list_del(&entry->nd);
- kfree(entry);
- err = 0;
- break;
- } else if (entry->start > start) {
- break;
- }
- }
-
- if (!err)
- goto unlock_ret;
-
- entry = saved_entry;
- list_for_each_entry_reverse(entry, &memtype_list, nd) {
- if (entry->start == start && entry->end == end) {
- rb_erase(&entry->rb, &memtype_rbroot);
- list_del(&entry->nd);
- kfree(entry);
- err = 0;
- break;
- } else if (entry->start < start) {
- break;
- }
- }
-unlock_ret:
+ err = rbt_memtype_erase(start, end);
spin_unlock(&memtype_lock);
if (err) {
@@ -599,7 +410,7 @@ static unsigned long lookup_memtype(u64 paddr)
spin_lock(&memtype_lock);
- entry = memtype_rb_search(&memtype_rbroot, paddr);
+ entry = rbt_memtype_lookup(paddr);
if (entry != NULL)
rettype = entry->type;
else
@@ -936,29 +747,25 @@ EXPORT_SYMBOL_GPL(pgprot_writecombine);
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
-/* get Nth element of the linked list */
static struct memtype *memtype_get_idx(loff_t pos)
{
- struct memtype *list_node, *print_entry;
- int i = 1;
+ struct memtype *print_entry;
+ int ret;
- print_entry = kmalloc(sizeof(struct memtype), GFP_KERNEL);
+ print_entry = kzalloc(sizeof(struct memtype), GFP_KERNEL);
if (!print_entry)
return NULL;
spin_lock(&memtype_lock);
- list_for_each_entry(list_node, &memtype_list, nd) {
- if (pos == i) {
- *print_entry = *list_node;
- spin_unlock(&memtype_lock);
- return print_entry;
- }
- ++i;
- }
+ ret = rbt_memtype_copy_nth_element(print_entry, pos);
spin_unlock(&memtype_lock);
- kfree(print_entry);
- return NULL;
+ if (!ret) {
+ return print_entry;
+ } else {
+ kfree(print_entry);
+ return NULL;
+ }
}
static void *memtype_seq_start(struct seq_file *seq, loff_t *pos)
diff --git a/arch/x86/mm/pat_internal.h b/arch/x86/mm/pat_internal.h
new file mode 100644
index 0000000..4f39eef
--- /dev/null
+++ b/arch/x86/mm/pat_internal.h
@@ -0,0 +1,46 @@
+#ifndef __PAT_INTERNAL_H_
+#define __PAT_INTERNAL_H_
+
+extern int pat_debug_enable;
+
+#define dprintk(fmt, arg...) \
+ do { if (pat_debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)
+
+struct memtype {
+ u64 start;
+ u64 end;
+ u64 subtree_max_end;
+ unsigned long type;
+ struct rb_node rb;
+};
+
+static inline char *cattr_name(unsigned long flags)
+{
+ switch (flags & _PAGE_CACHE_MASK) {
+ case _PAGE_CACHE_UC: return "uncached";
+ case _PAGE_CACHE_UC_MINUS: return "uncached-minus";
+ case _PAGE_CACHE_WB: return "write-back";
+ case _PAGE_CACHE_WC: return "write-combining";
+ default: return "broken";
+ }
+}
+
+#ifdef CONFIG_X86_PAT
+extern int rbt_memtype_check_insert(struct memtype *new,
+ unsigned long *new_type);
+extern int rbt_memtype_erase(u64 start, u64 end);
+extern struct memtype *rbt_memtype_lookup(u64 addr);
+extern int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos);
+#else
+static inline int rbt_memtype_check_insert(struct memtype *new,
+ unsigned long *new_type)
+{ return 0; }
+static inline int rbt_memtype_erase(u64 start, u64 end)
+{ return 0; }
+static inline struct memtype *rbt_memtype_lookup(u64 addr)
+{ return NULL; }
+static inline int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos)
+{ return 0; }
+#endif
+
+#endif /* __PAT_INTERNAL_H_ */
diff --git a/arch/x86/mm/pat_rbtree.c b/arch/x86/mm/pat_rbtree.c
new file mode 100644
index 0000000..9063f40
--- /dev/null
+++ b/arch/x86/mm/pat_rbtree.c
@@ -0,0 +1,271 @@
+/*
+ * Handle caching attributes in page tables (PAT)
+ *
+ * Authors: Venkatesh Pallipadi <venkatesh.pallipadi@...el.com>
+ * Suresh B Siddha <suresh.b.siddha@...el.com>
+ *
+ * Interval tree (augmented rbtree) used to store the PAT memory type
+ * reservations.
+ */
+
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/rbtree.h>
+#include <linux/sched.h>
+#include <linux/gfp.h>
+
+#include <asm/pgtable.h>
+#include <asm/pat.h>
+
+#include "pat_internal.h"
+
+/*
+ * The memtype tree keeps track of memory type for specific
+ * physical memory areas. Without proper tracking, conflicting memory
+ * types in different mappings can cause CPU cache corruption.
+ *
+ * The tree is an interval tree (augmented rbtree) with tree ordered
+ * on starting address. Tree can contain multiple entries for
+ * different regions which overlap. All the aliases have the same
+ * cache attributes of course.
+ *
+ * memtype_lock protects the rbtree.
+ */
+
+static void memtype_rb_augment_cb(struct rb_node *node);
+static struct rb_root memtype_rbroot = RB_AUGMENT_ROOT(&memtype_rb_augment_cb);
+
+static int is_node_overlap(struct memtype *node, u64 start, u64 end)
+{
+ if (node->start >= end || node->end <= start)
+ return 0;
+
+ return 1;
+}
+
+static u64 get_subtree_max_end(struct rb_node *node)
+{
+ u64 ret = 0;
+ if (node) {
+ struct memtype *data = container_of(node, struct memtype, rb);
+ ret = data->subtree_max_end;
+ }
+ return ret;
+}
+
+/* Update 'subtree_max_end' for a node, based on node and its children */
+static void update_node_max_end(struct rb_node *node)
+{
+ struct memtype *data;
+ u64 max_end, child_max_end;
+
+ if (!node)
+ return;
+
+ data = container_of(node, struct memtype, rb);
+ max_end = data->end;
+
+ child_max_end = get_subtree_max_end(node->rb_right);
+ if (child_max_end > max_end)
+ max_end = child_max_end;
+
+ child_max_end = get_subtree_max_end(node->rb_left);
+ if (child_max_end > max_end)
+ max_end = child_max_end;
+
+ data->subtree_max_end = max_end;
+}
+
+/* Update 'subtree_max_end' for a node and all its ancestors */
+static void update_path_max_end(struct rb_node *node)
+{
+ u64 old_max_end, new_max_end;
+
+ while (node) {
+ struct memtype *data = container_of(node, struct memtype, rb);
+
+ old_max_end = data->subtree_max_end;
+ update_node_max_end(node);
+ new_max_end = data->subtree_max_end;
+
+ if (new_max_end == old_max_end)
+ break;
+
+ node = rb_parent(node);
+ }
+}
+
+/* Find the first (lowest start addr) overlapping range from rb tree */
+static struct memtype *memtype_rb_lowest_match(struct rb_root *root,
+ u64 start, u64 end)
+{
+ struct rb_node *node = root->rb_node;
+ struct memtype *last_lower = NULL;
+
+ while (node) {
+ struct memtype *data = container_of(node, struct memtype, rb);
+
+ if (get_subtree_max_end(node->rb_left) > start) {
+ /* Lowest overlap if any must be on left side */
+ node = node->rb_left;
+ } else if (is_node_overlap(data, start, end)) {
+ last_lower = data;
+ break;
+ } else if (start >= data->start) {
+ /* Lowest overlap if any must be on right side */
+ node = node->rb_right;
+ } else {
+ break;
+ }
+ }
+ return last_lower; /* Returns NULL if there is no overlap */
+}
+
+static struct memtype *memtype_rb_exact_match(struct rb_root *root,
+ u64 start, u64 end)
+{
+ struct memtype *match;
+
+ match = memtype_rb_lowest_match(root, start, end);
+ while (match != NULL && match->start < end) {
+ struct rb_node *node;
+
+ if (match->start == start && match->end == end)
+ return match;
+
+ node = rb_next(&match->rb);
+ if (node)
+ match = container_of(node, struct memtype, rb);
+ else
+ match = NULL;
+ }
+
+ return NULL; /* Returns NULL if there is no exact match */
+}
+
+static int memtype_rb_check_conflict(struct rb_root *root,
+ u64 start, u64 end,
+ unsigned long reqtype, unsigned long *newtype)
+{
+ struct rb_node *node;
+ struct memtype *match;
+ int found_type = reqtype;
+
+ match = memtype_rb_lowest_match(&memtype_rbroot, start, end);
+ if (match == NULL)
+ goto success;
+
+ if (match->type != found_type && newtype == NULL)
+ goto failure;
+
+ dprintk("Overlap at 0x%Lx-0x%Lx\n", match->start, match->end);
+ found_type = match->type;
+
+ node = rb_next(&match->rb);
+ while (node) {
+ match = container_of(node, struct memtype, rb);
+
+ if (match->start >= end) /* Checked all possible matches */
+ goto success;
+
+ if (is_node_overlap(match, start, end) &&
+ match->type != found_type) {
+ goto failure;
+ }
+
+ node = rb_next(&match->rb);
+ }
+success:
+ if (newtype)
+ *newtype = found_type;
+
+ return 0;
+
+failure:
+ printk(KERN_INFO "%s:%d conflicting memory types "
+ "%Lx-%Lx %s<->%s\n", current->comm, current->pid, start,
+ end, cattr_name(found_type), cattr_name(match->type));
+ return -EBUSY;
+}
+
+static void memtype_rb_augment_cb(struct rb_node *node)
+{
+ if (node)
+ update_path_max_end(node);
+}
+
+static void memtype_rb_insert(struct rb_root *root, struct memtype *newdata)
+{
+ struct rb_node **node = &(root->rb_node);
+ struct rb_node *parent = NULL;
+
+ while (*node) {
+ struct memtype *data = container_of(*node, struct memtype, rb);
+
+ parent = *node;
+ if (newdata->start <= data->start)
+ node = &((*node)->rb_left);
+ else if (newdata->start > data->start)
+ node = &((*node)->rb_right);
+ }
+
+ rb_link_node(&newdata->rb, parent, node);
+ rb_insert_color(&newdata->rb, root);
+}
+
+int rbt_memtype_check_insert(struct memtype *new, unsigned long *ret_type)
+{
+ int err = 0;
+
+ err = memtype_rb_check_conflict(&memtype_rbroot, new->start, new->end,
+ new->type, ret_type);
+
+ if (!err) {
+ new->type = *ret_type;
+ memtype_rb_insert(&memtype_rbroot, new);
+ }
+ return err;
+}
+
+int rbt_memtype_erase(u64 start, u64 end)
+{
+ struct memtype *data;
+
+ data = memtype_rb_exact_match(&memtype_rbroot, start, end);
+ if (!data)
+ return -EINVAL;
+
+ rb_erase(&data->rb, &memtype_rbroot);
+ return 0;
+}
+
+struct memtype *rbt_memtype_lookup(u64 addr)
+{
+ struct memtype *data;
+ data = memtype_rb_lowest_match(&memtype_rbroot, addr, addr + PAGE_SIZE);
+ return data;
+}
+
+#if defined(CONFIG_DEBUG_FS)
+int rbt_memtype_copy_nth_element(struct memtype *out, loff_t pos)
+{
+ struct rb_node *node;
+ int i = 1;
+
+ node = rb_first(&memtype_rbroot);
+ while (node && pos != i) {
+ node = rb_next(node);
+ i++;
+ }
+
+ if (node) { /* pos == i */
+ struct memtype *this = container_of(node, struct memtype, rb);
+ *out = *this;
+ return 0;
+ } else {
+ return 1;
+ }
+}
+#endif
diff --git a/include/linux/rbtree.h b/include/linux/rbtree.h
index 9c29541..8e33a25 100644
--- a/include/linux/rbtree.h
+++ b/include/linux/rbtree.h
@@ -110,6 +110,7 @@ struct rb_node
struct rb_root
{
struct rb_node *rb_node;
+ void (*augment_cb)(struct rb_node *node);
};
@@ -129,7 +130,9 @@ static inline void rb_set_color(struct rb_node *rb, int color)
rb->rb_parent_color = (rb->rb_parent_color & ~1) | color;
}
-#define RB_ROOT (struct rb_root) { NULL, }
+#define RB_ROOT (struct rb_root) { NULL, NULL, }
+#define RB_AUGMENT_ROOT(x) (struct rb_root) { NULL, x}
+
#define rb_entry(ptr, type, member) container_of(ptr, type, member)
#define RB_EMPTY_ROOT(root) ((root)->rb_node == NULL)
diff --git a/lib/rbtree.c b/lib/rbtree.c
index e2aa3be..15e10b1 100644
--- a/lib/rbtree.c
+++ b/lib/rbtree.c
@@ -44,6 +44,11 @@ static void __rb_rotate_left(struct rb_node *node, struct rb_root *root)
else
root->rb_node = right;
rb_set_parent(node, right);
+
+ if (root->augment_cb) {
+ root->augment_cb(node);
+ root->augment_cb(right);
+ }
}
static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
@@ -67,12 +72,20 @@ static void __rb_rotate_right(struct rb_node *node, struct rb_root *root)
else
root->rb_node = left;
rb_set_parent(node, left);
+
+ if (root->augment_cb) {
+ root->augment_cb(node);
+ root->augment_cb(left);
+ }
}
void rb_insert_color(struct rb_node *node, struct rb_root *root)
{
struct rb_node *parent, *gparent;
+ if (root->augment_cb)
+ root->augment_cb(node);
+
while ((parent = rb_parent(node)) && rb_is_red(parent))
{
gparent = rb_parent(parent);
@@ -227,12 +240,15 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
else
{
struct rb_node *old = node, *left;
+ int old_parent_cb = 0;
+ int successor_parent_cb = 0;
node = node->rb_right;
while ((left = node->rb_left) != NULL)
node = left;
if (rb_parent(old)) {
+ old_parent_cb = 1;
if (rb_parent(old)->rb_left == old)
rb_parent(old)->rb_left = node;
else
@@ -247,8 +263,10 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
if (parent == old) {
parent = node;
} else {
+ successor_parent_cb = 1;
if (child)
rb_set_parent(child, parent);
+
parent->rb_left = child;
node->rb_right = old->rb_right;
@@ -259,6 +277,24 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
node->rb_left = old->rb_left;
rb_set_parent(old->rb_left, node);
+ if (root->augment_cb) {
+ /*
+ * Here, three different nodes can have new children.
+ * The parent of the successor node that was selected
+ * to replace the node to be erased.
+ * The node that is getting erased and is now replaced
+ * by its successor.
+ * The parent of the node getting erased-replaced.
+ */
+ if (successor_parent_cb)
+ root->augment_cb(parent);
+
+ root->augment_cb(node);
+
+ if (old_parent_cb)
+ root->augment_cb(rb_parent(old));
+ }
+
goto color;
}
@@ -267,15 +303,19 @@ void rb_erase(struct rb_node *node, struct rb_root *root)
if (child)
rb_set_parent(child, parent);
- if (parent)
- {
+
+ if (parent) {
if (parent->rb_left == node)
parent->rb_left = child;
else
parent->rb_right = child;
- }
- else
+
+ if (root->augment_cb)
+ root->augment_cb(parent);
+
+ } else {
root->rb_node = child;
+ }
color:
if (color == RB_BLACK)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists