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From akpm@osdl.org Fri Jun 30 16:33:01 2006
From: Matthew Wilcox <matthew@wil.cx>
Message-Id: <200606300931.k5U9VOdN001627@shell0.pdx.osdl.net>
Subject: Resources: insert identical resources above existing resources
To: greg@kroah.com
Cc: akpm@osdl.org, matthew@wil.cx, ink@jurassic.park.msu.ru, linux@dominikbrodowski.net
Date: Fri, 30 Jun 2006 02:31:24 -0700
From: Matthew Wilcox <matthew@wil.cx>
If you have two resources which aree exactly the same size,
insert_resource() currently inserts the new one below the existing one.
This is wrong because there's no way to insert a resource of the same size
above an existing one.
I took this opportunity to rewrite the initial loop to be a for-loop
instead of a goto-loop and fix the documentation.
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
kernel/resource.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)
--- gregkh-2.6.orig/kernel/resource.c
+++ gregkh-2.6/kernel/resource.c
@@ -341,12 +341,11 @@ EXPORT_SYMBOL(allocate_resource);
*
* Returns 0 on success, -EBUSY if the resource can't be inserted.
*
- * This function is equivalent of request_resource when no conflict
+ * This function is equivalent to request_resource when no conflict
* happens. If a conflict happens, and the conflicting resources
* entirely fit within the range of the new resource, then the new
- * resource is inserted and the conflicting resources become childs of
- * the new resource. Otherwise the new resource becomes the child of
- * the conflicting resource
+ * resource is inserted and the conflicting resources become children of
+ * the new resource.
*/
int insert_resource(struct resource *parent, struct resource *new)
{
@@ -354,20 +353,21 @@ int insert_resource(struct resource *par
struct resource *first, *next;
write_lock(&resource_lock);
- begin:
- result = 0;
- first = __request_resource(parent, new);
- if (!first)
- goto out;
- result = -EBUSY;
- if (first == parent)
- goto out;
+ for (;; parent = first) {
+ result = 0;
+ first = __request_resource(parent, new);
+ if (!first)
+ goto out;
- /* Resource fully contained by the clashing resource? Recurse into it */
- if (first->start <= new->start && first->end >= new->end) {
- parent = first;
- goto begin;
+ result = -EBUSY;
+ if (first == parent)
+ goto out;
+
+ if ((first->start > new->start) || (first->end < new->end))
+ break;
+ if ((first->start == new->start) && (first->end == new->end))
+ break;
}
for (next = first; ; next = next->sibling) {
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