Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=7aae6dd80e265aa9402ed507caaff4a5dba55069
Commit: 7aae6dd80e265aa9402ed507caaff4a5dba55069
Parent: dc0afa8388972a9ed7c2203cc46d8df1a4713f65
Author: Tejun Heo <[EMAIL PROTECTED]>
AuthorDate: Thu Jun 14 03:45:12 2007 +0900
Committer: Greg Kroah-Hartman <[EMAIL PROTECTED]>
CommitDate: Wed Jul 11 16:09:02 2007 -0700
idr: fix obscure bug in allocation path
In sub_alloc(), when bitmap search fails, it goes up one level to
continue search. This is done by updating the id cursor and searching
the upper level again. If the cursor was at the end of the upper
level, we need to go further than that.
This wasn't implemented and when that happens the part of the cursor
which indexes into the upper level wraps and sub_alloc() ends up
searching the wrong bitmap. It allocates id which doesn't match the
actual slot.
This patch fixes this by restarting from the top if the search needs
to go higher than one level.
Signed-off-by: Tejun Heo <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
lib/idr.c | 16 ++++++++++++++--
1 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/lib/idr.c b/lib/idr.c
index 305117c..7b5a59c 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -100,10 +100,11 @@ static int sub_alloc(struct idr *idp, void *ptr, int
*starting_id)
int n, m, sh;
struct idr_layer *p, *new;
struct idr_layer *pa[MAX_LEVEL];
- int l, id;
+ int l, id, oid;
long bm;
id = *starting_id;
+ restart:
p = idp->top;
l = idp->layers;
pa[l--] = NULL;
@@ -117,12 +118,23 @@ static int sub_alloc(struct idr *idp, void *ptr, int
*starting_id)
if (m == IDR_SIZE) {
/* no space available go back to previous layer. */
l++;
+ oid = id;
id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
+
+ /* if already at the top layer, we need to grow */
if (!(p = pa[l])) {
*starting_id = id;
return -2;
}
- continue;
+
+ /* If we need to go up one layer, continue the
+ * loop; otherwise, restart from the top.
+ */
+ sh = IDR_BITS * (l + 1);
+ if (oid >> sh == id >> sh)
+ continue;
+ else
+ goto restart;
}
if (m != n) {
sh = IDR_BITS*l;
-
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