Commit 711a49a0 authored Dec 10, 2008 by Manfred Spraul Committed by Linus Torvalds Dec 10, 2008

lib/idr.c: Fix bug introduced by RCU fix



The last patch to lib/idr.c caused a bug if idr_get_new_above() was
called on an empty idr.

Usually, nodes stay on the same layer.  New layers are added to the top
of the tree.

The exception is idr_get_new_above() on an empty tree: In this case, the
new root node is first added on layer 0, then moved upwards.  p->layer
was not updated.

As usual: You shall never rely on the source code comments, they will
only mislead you.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent c7f8d6f6

lib/idr.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -220,8 +220,14 @@ build_up:
		*/
		while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) {
		layers++;
		if (!p->count)
		if (!p->count) {
		/* special case: if the tree is currently empty,
		* then we grow the tree by moving the top node
		* upwards.
		*/
		p->layer++;
		continue;
		}
		if (!(new = get_from_free_list(idp))) {
		/*
		* The allocation failed. If we built part of

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