aboutsummaryrefslogtreecommitdiffstats
path: root/target/linux/generic/pending-3.18/080-20-fib_trie-Fix-RCU-bug-and-merge-similar-bits-of-infla.patch
diff options
context:
space:
mode:
Diffstat (limited to 'target/linux/generic/pending-3.18/080-20-fib_trie-Fix-RCU-bug-and-merge-similar-bits-of-infla.patch')
-rw-r--r--target/linux/generic/pending-3.18/080-20-fib_trie-Fix-RCU-bug-and-merge-similar-bits-of-infla.patch267
1 files changed, 0 insertions, 267 deletions
diff --git a/target/linux/generic/pending-3.18/080-20-fib_trie-Fix-RCU-bug-and-merge-similar-bits-of-infla.patch b/target/linux/generic/pending-3.18/080-20-fib_trie-Fix-RCU-bug-and-merge-similar-bits-of-infla.patch
deleted file mode 100644
index 7e26127084..0000000000
--- a/target/linux/generic/pending-3.18/080-20-fib_trie-Fix-RCU-bug-and-merge-similar-bits-of-infla.patch
+++ /dev/null
@@ -1,267 +0,0 @@
-From: Alexander Duyck <alexander.h.duyck@redhat.com>
-Date: Thu, 22 Jan 2015 15:51:14 -0800
-Subject: [PATCH] fib_trie: Fix RCU bug and merge similar bits of inflate/halve
-
-This patch addresses two issues.
-
-The first issue is the fact that I believe I had the RCU freeing sequence
-slightly out of order. As a result we could get into an issue if a caller
-went into a child of a child of the new node, then backtraced into the to be
-freed parent, and then attempted to access a child of a child that may have
-been consumed in a resize of one of the new nodes children. To resolve this I
-have moved the resize after we have freed the oldtnode. The only side effect
-of this is that we will now be calling resize on more nodes in the case of
-inflate due to the fact that we don't have a good way to test to see if a
-full_tnode on the new node was there before or after the allocation. This
-should have minimal impact however since the node should already be
-correctly size so it is just the cost of calling should_inflate that we
-will be taking on the node which is only a couple of cycles.
-
-The second issue is the fact that inflate and halve were essentially doing
-the same thing after the new node was added to the trie replacing the old
-one. As such it wasn't really necessary to keep the code in both functions
-so I have split it out into two other functions, called replace and
-update_children.
-
-Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
-Signed-off-by: David S. Miller <davem@davemloft.net>
----
-
---- a/net/ipv4/fib_trie.c
-+++ b/net/ipv4/fib_trie.c
-@@ -396,8 +396,30 @@ static void put_child(struct tnode *tn,
- rcu_assign_pointer(tn->child[i], n);
- }
-
--static void put_child_root(struct tnode *tp, struct trie *t,
-- t_key key, struct tnode *n)
-+static void update_children(struct tnode *tn)
-+{
-+ unsigned long i;
-+
-+ /* update all of the child parent pointers */
-+ for (i = tnode_child_length(tn); i;) {
-+ struct tnode *inode = tnode_get_child(tn, --i);
-+
-+ if (!inode)
-+ continue;
-+
-+ /* Either update the children of a tnode that
-+ * already belongs to us or update the child
-+ * to point to ourselves.
-+ */
-+ if (node_parent(inode) == tn)
-+ update_children(inode);
-+ else
-+ node_set_parent(inode, tn);
-+ }
-+}
-+
-+static inline void put_child_root(struct tnode *tp, struct trie *t,
-+ t_key key, struct tnode *n)
- {
- if (tp)
- put_child(tp, get_index(key, tp), n);
-@@ -434,10 +456,35 @@ static void tnode_free(struct tnode *tn)
- }
- }
-
-+static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)
-+{
-+ struct tnode *tp = node_parent(oldtnode);
-+ unsigned long i;
-+
-+ /* setup the parent pointer out of and back into this node */
-+ NODE_INIT_PARENT(tn, tp);
-+ put_child_root(tp, t, tn->key, tn);
-+
-+ /* update all of the child parent pointers */
-+ update_children(tn);
-+
-+ /* all pointers should be clean so we are done */
-+ tnode_free(oldtnode);
-+
-+ /* resize children now that oldtnode is freed */
-+ for (i = tnode_child_length(tn); i;) {
-+ struct tnode *inode = tnode_get_child(tn, --i);
-+
-+ /* resize child node */
-+ if (tnode_full(tn, inode))
-+ resize(t, inode);
-+ }
-+}
-+
- static int inflate(struct trie *t, struct tnode *oldtnode)
- {
-- struct tnode *inode, *node0, *node1, *tn, *tp;
-- unsigned long i, j, k;
-+ struct tnode *tn;
-+ unsigned long i;
- t_key m;
-
- pr_debug("In inflate\n");
-@@ -446,13 +493,18 @@ static int inflate(struct trie *t, struc
- if (!tn)
- return -ENOMEM;
-
-+ /* prepare oldtnode to be freed */
-+ tnode_free_init(oldtnode);
-+
- /* Assemble all of the pointers in our cluster, in this case that
- * represents all of the pointers out of our allocated nodes that
- * point to existing tnodes and the links between our allocated
- * nodes.
- */
- for (i = tnode_child_length(oldtnode), m = 1u << tn->pos; i;) {
-- inode = tnode_get_child(oldtnode, --i);
-+ struct tnode *inode = tnode_get_child(oldtnode, --i);
-+ struct tnode *node0, *node1;
-+ unsigned long j, k;
-
- /* An empty child */
- if (inode == NULL)
-@@ -464,6 +516,9 @@ static int inflate(struct trie *t, struc
- continue;
- }
-
-+ /* drop the node in the old tnode free list */
-+ tnode_free_append(oldtnode, inode);
-+
- /* An internal node with two children */
- if (inode->bits == 1) {
- put_child(tn, 2 * i + 1, tnode_get_child(inode, 1));
-@@ -488,9 +543,9 @@ static int inflate(struct trie *t, struc
- node1 = tnode_new(inode->key | m, inode->pos, inode->bits - 1);
- if (!node1)
- goto nomem;
-- tnode_free_append(tn, node1);
-+ node0 = tnode_new(inode->key, inode->pos, inode->bits - 1);
-
-- node0 = tnode_new(inode->key & ~m, inode->pos, inode->bits - 1);
-+ tnode_free_append(tn, node1);
- if (!node0)
- goto nomem;
- tnode_free_append(tn, node0);
-@@ -512,53 +567,9 @@ static int inflate(struct trie *t, struc
- put_child(tn, 2 * i, node0);
- }
-
-- /* setup the parent pointer into and out of this node */
-- tp = node_parent(oldtnode);
-- NODE_INIT_PARENT(tn, tp);
-- put_child_root(tp, t, tn->key, tn);
-+ /* setup the parent pointers into and out of this node */
-+ replace(t, oldtnode, tn);
-
-- /* prepare oldtnode to be freed */
-- tnode_free_init(oldtnode);
--
-- /* update all child nodes parent pointers to route to us */
-- for (i = tnode_child_length(oldtnode); i;) {
-- inode = tnode_get_child(oldtnode, --i);
--
-- /* A leaf or an internal node with skipped bits */
-- if (!tnode_full(oldtnode, inode)) {
-- node_set_parent(inode, tn);
-- continue;
-- }
--
-- /* drop the node in the old tnode free list */
-- tnode_free_append(oldtnode, inode);
--
-- /* fetch new nodes */
-- node1 = tnode_get_child(tn, 2 * i + 1);
-- node0 = tnode_get_child(tn, 2 * i);
--
-- /* bits == 1 then node0 and node1 represent inode's children */
-- if (inode->bits == 1) {
-- node_set_parent(node1, tn);
-- node_set_parent(node0, tn);
-- continue;
-- }
--
-- /* update parent pointers in child node's children */
-- for (k = tnode_child_length(inode), j = k / 2; j;) {
-- node_set_parent(tnode_get_child(inode, --k), node1);
-- node_set_parent(tnode_get_child(inode, --j), node0);
-- node_set_parent(tnode_get_child(inode, --k), node1);
-- node_set_parent(tnode_get_child(inode, --j), node0);
-- }
--
-- /* resize child nodes */
-- resize(t, node1);
-- resize(t, node0);
-- }
--
-- /* we completed without error, prepare to free old node */
-- tnode_free(oldtnode);
- return 0;
- nomem:
- /* all pointers should be clean so we are done */
-@@ -568,7 +579,7 @@ nomem:
-
- static int halve(struct trie *t, struct tnode *oldtnode)
- {
-- struct tnode *tn, *tp, *inode, *node0, *node1;
-+ struct tnode *tn;
- unsigned long i;
-
- pr_debug("In halve\n");
-@@ -577,14 +588,18 @@ static int halve(struct trie *t, struct
- if (!tn)
- return -ENOMEM;
-
-+ /* prepare oldtnode to be freed */
-+ tnode_free_init(oldtnode);
-+
- /* Assemble all of the pointers in our cluster, in this case that
- * represents all of the pointers out of our allocated nodes that
- * point to existing tnodes and the links between our allocated
- * nodes.
- */
- for (i = tnode_child_length(oldtnode); i;) {
-- node1 = tnode_get_child(oldtnode, --i);
-- node0 = tnode_get_child(oldtnode, --i);
-+ struct tnode *node1 = tnode_get_child(oldtnode, --i);
-+ struct tnode *node0 = tnode_get_child(oldtnode, --i);
-+ struct tnode *inode;
-
- /* At least one of the children is empty */
- if (!node1 || !node0) {
-@@ -609,34 +624,8 @@ static int halve(struct trie *t, struct
- put_child(tn, i / 2, inode);
- }
-
-- /* setup the parent pointer out of and back into this node */
-- tp = node_parent(oldtnode);
-- NODE_INIT_PARENT(tn, tp);
-- put_child_root(tp, t, tn->key, tn);
--
-- /* prepare oldtnode to be freed */
-- tnode_free_init(oldtnode);
--
-- /* update all of the child parent pointers */
-- for (i = tnode_child_length(tn); i;) {
-- inode = tnode_get_child(tn, --i);
--
-- /* only new tnodes will be considered "full" nodes */
-- if (!tnode_full(tn, inode)) {
-- node_set_parent(inode, tn);
-- continue;
-- }
--
-- /* Two nonempty children */
-- node_set_parent(tnode_get_child(inode, 1), inode);
-- node_set_parent(tnode_get_child(inode, 0), inode);
--
-- /* resize child node */
-- resize(t, inode);
-- }
--
-- /* all pointers should be clean so we are done */
-- tnode_free(oldtnode);
-+ /* setup the parent pointers into and out of this node */
-+ replace(t, oldtnode, tn);
-
- return 0;
- }
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-28 06:19:51 +0000