lib/rbtree.c: fix typo in comment of ____rb_erase_color (ce093a04) · Commits · 戴 / test

In Case 3 of `sibling == parent->rb_right': Right rotation will not change color of sl and S in the diagram (i.e. should not change "sl" to "Sl", "S" to "s") In Case 3 of `sibling == parent->rb_left': (p) (p) / \ / \ S N --> sr N / \ / Sl sr S / Sl This is actually left rotation at "S", not right rotation. In Case 4 of `sibling == parent->rb_left': (p) (s) / \ / \ S N --> Sl P / \ / \ sl (sr) (sr) N This is actually right rotation at "(p)" + color flips, not left rotation + color flips. Link: http://lkml.kernel.org/r/1472391115-3702-1-git-send-email-fykcee1@gmail.com Signed-off-by:

Jie Chen <fykcee1@gmail.com> Cc: Wei Yang <weiyang@linux.vnet.ibm.com> Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

lib/rbtree.c

+19 −4

Original line number	Diff line number	Diff line
		@@ -296,9 +296,24 @@ ____rb_erase_color(struct rb_node parent, struct rb_root root,
		*
		* (p) (p)
		* / \ / \
		* N S --> N Sl
		* N S --> N sl
		* / \ \
		* sl Sr s
		* sl Sr S
		* \
		* Sr
		*
		* Note: p might be red, and then both
		* p and sl are red after rotation(which
		* breaks property 4). This is fixed in
		* Case 4 (in __rb_rotate_set_parents()
		* which set sl the color of p
		* and set p RB_BLACK)
		*
		* (p) (sl)
		* / \ / \
		* N sl --> P S
		* \ / \
		* S N Sr
		* \
		* Sr
		*/
		@@ -365,7 +380,7 @@ ____rb_erase_color(struct rb_node parent, struct rb_root root,
		}
		break;
		}
		/* Case 3 - right rotate at sibling */
		/* Case 3 - left rotate at sibling */
		tmp1 = tmp2->rb_left;
		WRITE_ONCE(sibling->rb_right, tmp1);
		WRITE_ONCE(tmp2->rb_left, sibling);
		@@ -377,7 +392,7 @@ ____rb_erase_color(struct rb_node parent, struct rb_root root,
		tmp1 = sibling;
		sibling = tmp2;
		}
		/* Case 4 - left rotate at parent + color flips */
		/* Case 4 - right rotate at parent + color flips */
		tmp2 = sibling->rb_right;
		WRITE_ONCE(parent->rb_left, tmp2);
		WRITE_ONCE(sibling->rb_right, parent);

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