[PATCH] Get rid of check_resource() before it becomes a problem

The new resource interface foolishly replicated the (obsolete,
racy) spirit of the check_region call as check_resource.  You
should use request_resource/release_resource instead.

drivers/pcmcia/rsrc_mgr.c

@@ -124,16 +124,36 @@ static struct resource *resource_parent(unsigned long b, unsigned long n,
 	return &ioport_resource;
 }
 
+/* FIXME: Fundamentally racy. */
 static inline int check_io_resource(unsigned long b, unsigned long n,
 				    struct pci_dev *dev)
 {
-	return check_resource(resource_parent(b, n, IORESOURCE_IO, dev), b, n);
+	struct resource *region;
+
+	region = __request_region(resource_parent(b, n, IORESOURCE_IO, dev),
+				  b, n, "check_io_resource");
+	if (!region)
+		return -EBUSY;
+
+	release_resource(region);
+	kfree(region);
+	return 0;
 }
 
+/* FIXME: Fundamentally racy. */
 static inline int check_mem_resource(unsigned long b, unsigned long n,
 				     struct pci_dev *dev)
 {
-	return check_resource(resource_parent(b, n, IORESOURCE_MEM, dev), b, n);
+	struct resource *region;
+
+	region = __request_region(resource_parent(b, n, IORESOURCE_MEM, dev),
+				  b, n, "check_mem_resource");
+	if (!region)
+		return -EBUSY;
+
+	release_resource(region);
+	kfree(region);
+	return 0;
 }
 
 static struct resource *make_resource(unsigned long b, unsigned long n,

include/linux/ioport.h

@@ -85,7 +85,6 @@ extern struct resource iomem_resource;
 
 extern int get_resource_list(struct resource *, char *buf, int size);
 
-extern int check_resource(struct resource *root, unsigned long, unsigned long);
 extern int request_resource(struct resource *root, struct resource *new);
 extern int release_resource(struct resource *new);
 extern int allocate_resource(struct resource *root, struct resource *new,

kernel/ksyms.c

@@ -445,7 +445,6 @@ EXPORT_SYMBOL(enable_hlt);
 EXPORT_SYMBOL(request_resource);
 EXPORT_SYMBOL(release_resource);
 EXPORT_SYMBOL(allocate_resource);
-EXPORT_SYMBOL(check_resource);
 EXPORT_SYMBOL(__request_region);
 EXPORT_SYMBOL(__check_region);
 EXPORT_SYMBOL(__release_region);

kernel/resource.c

@@ -131,20 +131,6 @@ int release_resource(struct resource *old)
 	return retval;
 }
 
-int check_resource(struct resource *root, unsigned long start, unsigned long len)
-{
-	struct resource *conflict, tmp;
-
-	tmp.start = start;
-	tmp.end = start + len - 1;
-	write_lock(&resource_lock);
-	conflict = __request_resource(root, &tmp);
-	if (!conflict)
-		__release_resource(&tmp);
-	write_unlock(&resource_lock);
-	return conflict ? -EBUSY : 0;
-}
-
 /*
  * Find empty slot in the resource tree given range and alignment.
  */