resource: add resource_size()

Avoid one-off errors by introducing a resource_size() function.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 2cd07cc29687..22d2115458c6 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -118,6 +118,10 @@ extern int allocate_resource(struct resource *root, struct resource *new,
 int adjust_resource(struct resource *res, resource_size_t start,
                     resource_size_t size);
 resource_size_t resource_alignment(struct resource *res);
+static inline resource_size_t resource_size(struct resource *res)
+{
+        return res->end - res->start + 1;
+}
 
 /* Convenience shorthand with allocation */
 #define request_region(start,n,name)    __request_region(&ioport_resource, (start), (n), (name))