Eric Lee / linux-smarc-t335x-v3.2

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Commit 711a49a07f84f914aac26a52143f6e7526571143

Authored by Manfred Spraul
Committed by Linus Torvalds
1 parent c7f8d6f6b5
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

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>

Showing 1 changed file with 7 additions and 1 deletions Side-by-side Diff

... ... @@ -220,8 +220,14 @@
220 220 */
221 221 while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) {
222 222 layers++;
223   - if (!p->count)
  223 + if (!p->count) {
  224 + /* special case: if the tree is currently empty,
  225 + * then we grow the tree by moving the top node
  226 + * upwards.
  227 + */
  228 + p->layer++;
224 229 continue;
  230 + }
225 231 if (!(new = get_from_free_list(idp))) {
226 232 /*
227 233 * The allocation failed. If we built part of