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| author | Davidlohr Bueso <dave@stgolabs.net> | 2017-09-08 16:14:42 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-08 18:26:48 -0700 |
| commit | 35dc67d7d922b2c9a1adb006c7a0f370eeb5c114 (patch) | |
| tree | 5f9f7154581152b4557d7cf7e64179fccbc02209 | |
| parent | 2aadf7fc7df9e70c99786ffb8452ccdd83d49e59 (diff) | |
| download | lwn-35dc67d7d922b2c9a1adb006c7a0f370eeb5c114.tar.gz lwn-35dc67d7d922b2c9a1adb006c7a0f370eeb5c114.zip | |
rbtree: add some additional comments for rebalancing cases
While overall the code is very nicely commented, it might not be
immediately obvious from the diagrams what is going on. Add a very
brief summary of each case. Opposite cases where the node is the left
child are left untouched.
Link: http://lkml.kernel.org/r/20170719014603.19029-4-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | lib/rbtree.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/lib/rbtree.c b/lib/rbtree.c index e7cce12f404f..ba4a9d165f1b 100644 --- a/lib/rbtree.c +++ b/lib/rbtree.c @@ -132,7 +132,7 @@ __rb_insert(struct rb_node *node, struct rb_root *root, if (parent != tmp) { /* parent == gparent->rb_left */ if (tmp && rb_is_red(tmp)) { /* - * Case 1 - color flips + * Case 1 - node's uncle is red (color flips). * * G g * / \ / \ @@ -155,7 +155,8 @@ __rb_insert(struct rb_node *node, struct rb_root *root, tmp = parent->rb_right; if (node == tmp) { /* - * Case 2 - left rotate at parent + * Case 2 - node's uncle is black and node is + * the parent's right child (left rotate at parent). * * G G * / \ / \ @@ -179,7 +180,8 @@ __rb_insert(struct rb_node *node, struct rb_root *root, } /* - * Case 3 - right rotate at gparent + * Case 3 - node's uncle is black and node is + * the parent's left child (right rotate at gparent). * * G P * / \ / \ |