From 5a3cbef53373a0e9a24c8b605fb0ac163913bec3 Mon Sep 17 00:00:00 2001
From: Sapan Bhatia <sapanb@cs.princeton.edu>
Date: Sat, 28 Feb 2009 08:10:37 +0000
Subject: [PATCH] Garbage collect dcookies to plug a memory hole in Chopstix.
---
linux-2.6-590-GC-dcookies.patch | 139 ++++++++++++++++++++++++++++++++
1 file changed, 139 insertions(+)
create mode 100644 linux-2.6-590-GC-dcookies.patch
diff --git a/linux-2.6-590-GC-dcookies.patch b/linux-2.6-590-GC-dcookies.patch
new file mode 100644
index 000000000..bf9c6f2eb
--- /dev/null
+++ b/linux-2.6-590-GC-dcookies.patch
@@ -0,0 +1,139 @@
+--- linux-2.6.22.19-chopstix/fs/dcookies.c 2009-02-28 03:10:05.000000000 -0500
++++ linux-2.6.22.19-chopstix/fs/dcookies.c.orig 2008-02-25 18:59:40.000000000 -0500
+@@ -38,19 +38,14 @@
+ static LIST_HEAD(dcookie_users);
+ static DEFINE_MUTEX(dcookie_mutex);
+ static struct kmem_cache *dcookie_cache __read_mostly;
+-static struct list_head *dcookie_hashtable[2] __read_mostly;
++static struct list_head *dcookie_hashtable __read_mostly;
+ static size_t hash_size __read_mostly;
+-unsigned int current_hash = 0;
+
+ static inline int is_live(void)
+ {
+ return !(list_empty(&dcookie_users));
+ }
+
+-static inline int is_shared(void)
+-{
+- return !(list_empty(&dcookie_users)) && !(list_empty(dcookie_users.next));
+-}
+
+ /* The dentry is locked, its address will do for the cookie */
+ static inline unsigned long dcookie_value(struct dcookie_struct * dcs)
+@@ -72,7 +67,7 @@
+ struct list_head * pos;
+ struct list_head * list;
+
+- list = dcookie_hashtable[current_hash] + dcookie_hash(dcookie);
++ list = dcookie_hashtable + dcookie_hash(dcookie);
+
+ list_for_each(pos, list) {
+ dcs = list_entry(pos, struct dcookie_struct, hash_list);
+@@ -88,7 +83,7 @@
+
+ static void hash_dcookie(struct dcookie_struct * dcs)
+ {
+- struct list_head * list = dcookie_hashtable[current_hash] + dcookie_hash(dcookie_value(dcs));
++ struct list_head * list = dcookie_hashtable + dcookie_hash(dcookie_value(dcs));
+ list_add(&dcs->hash_list, list);
+ }
+
+@@ -96,7 +91,7 @@
+ static struct dcookie_struct * alloc_dcookie(struct dentry * dentry,
+ struct vfsmount * vfsmnt)
+ {
+- struct dcookie_struct * dcs = kmem_cache_alloc(dcookie_cache, GFP_ATOMIC);
++ struct dcookie_struct * dcs = kmem_cache_alloc(dcookie_cache, GFP_KERNEL);
+ if (!dcs)
+ return NULL;
+
+@@ -215,12 +210,8 @@
+ if (!dcookie_cache)
+ goto out;
+
+- dcookie_hashtable[0] = kmalloc(PAGE_SIZE, GFP_KERNEL);
+- if (!dcookie_hashtable[0])
+- goto out_kmem;
+-
+- dcookie_hashtable[1] = kmalloc(PAGE_SIZE, GFP_KERNEL);
+- if (!dcookie_hashtable[1])
++ dcookie_hashtable = kmalloc(PAGE_SIZE, GFP_KERNEL);
++ if (!dcookie_hashtable)
+ goto out_kmem;
+
+ err = 0;
+@@ -244,15 +235,7 @@
+ hash_size = 1UL << hash_bits;
+
+ /* And initialize the newly allocated array */
+- d = dcookie_hashtable[0];
+- i = hash_size;
+- do {
+- INIT_LIST_HEAD(d);
+- d++;
+- i--;
+- } while (i);
+-
+- d = dcookie_hashtable[1];
++ d = dcookie_hashtable;
+ i = hash_size;
+ do {
+ INIT_LIST_HEAD(d);
+@@ -276,30 +259,6 @@
+ kmem_cache_free(dcookie_cache, dcs);
+ }
+
+-/* Switch to the second hash */
+-int garbage_collect(void) {
+- struct list_head * list;
+- struct list_head * pos;
+- struct list_head * pos2;
+- struct dcookie_struct * dcs;
+- size_t i;
+-
+- if (is_shared())
+- return -EAGAIN;
+-
+- for (i = 0; i < hash_size; ++i) {
+- list = dcookie_hashtable[current_hash] + i;
+- list_for_each_safe(pos, pos2, list) {
+- dcs = list_entry(pos, struct dcookie_struct, hash_list);
+- list_del(&dcs->hash_list);
+- free_dcookie(dcs);
+- }
+- }
+-
+- current_hash = (current_hash & 1) ^ 1;
+-
+- return 0;
+-}
+
+ static void dcookie_exit(void)
+ {
+@@ -310,14 +269,7 @@
+ size_t i;
+
+ for (i = 0; i < hash_size; ++i) {
+- list = dcookie_hashtable[0] + i;
+- list_for_each_safe(pos, pos2, list) {
+- dcs = list_entry(pos, struct dcookie_struct, hash_list);
+- list_del(&dcs->hash_list);
+- free_dcookie(dcs);
+- }
+-
+- list = dcookie_hashtable[1] + i;
++ list = dcookie_hashtable + i;
+ list_for_each_safe(pos, pos2, list) {
+ dcs = list_entry(pos, struct dcookie_struct, hash_list);
+ list_del(&dcs->hash_list);
+@@ -325,8 +277,7 @@
+ }
+ }
+
+- kfree(dcookie_hashtable[0]);
+- kfree(dcookie_hashtable[1]);
++ kfree(dcookie_hashtable);
+ kmem_cache_destroy(dcookie_cache);
+ }
+
--
2.47.0