Commit 8a866fee authored Oct 08, 2017 by Sean Young Committed by Mauro Carvalho Chehab Dec 14, 2017

kfifo: DECLARE_KIFO_PTR(fifo, u64) does not work on arm 32 bit



If you try to store u64 in a kfifo (or a struct with u64 members),
then the buf member of __STRUCT_KFIFO_PTR will cause 4 bytes
padding due to alignment (note that struct __kfifo is 20 bytes
on 32 bit).

That in turn causes the __is_kfifo_ptr() to fail, which is caught
by kfifo_alloc(), which now returns EINVAL.

So, ensure that __is_kfifo_ptr() compares to the right structure.

Signed-off-by: Sean Young <sean@mess.org>
Acked-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

parent 62d6f199

include/linux/kfifo.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -113,7 +113,8 @@ struct kfifo_rec_ptr_2 __STRUCT_KFIFO_PTR(unsigned char, 2, void);
		* array is a part of the structure and the fifo type where the array is
		* outside of the fifo structure.
		*/
		#define __is_kfifo_ptr(fifo) (sizeof(*fifo) == sizeof(struct __kfifo))
		#define __is_kfifo_ptr(fifo) \
		(sizeof(fifo) == sizeof(STRUCT_KFIFO_PTR(typeof((fifo)->type))))

		/**
		* DECLARE_KFIFO_PTR - macro to declare a fifo pointer object