Re: [PATCH 01/12] ARM: ixp4xx: fix ioport_unmap definition

From: Krzysztof HaÅasa
Date: Fri Jul 21 2017 - 08:29:51 EST


Arnd Bergmann <arnd@xxxxxxxx> writes:

> An empty macro definition can cause unexpected behavior, in
> case of the ixp4xx ioport_unmap, we get two warnings:
>
> drivers/net/wireless/marvell/libertas/if_cs.c: In function 'if_cs_release':
> drivers/net/wireless/marvell/libertas/if_cs.c:826:3: error: suggest braces around empty body in an 'if' statement [-Werror=empty-body]
> ioport_unmap(card->iobase);
> drivers/vfio/pci/vfio_pci_rdwr.c: In function 'vfio_pci_vga_rw':
> drivers/vfio/pci/vfio_pci_rdwr.c:230:15: error: the omitted middle operand in ?: will always be 'true', suggest explicit middle operand [-Werror=parentheses]
> is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
>
> This uses an inline function to define the macro in a safer way.
>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> arch/arm/mach-ixp4xx/include/mach/io.h | 11 +++++++++--

Acked-by: Krzysztof Halasa <khalasa@xxxxxxx>

In fact, the old code contained another bug (missing parentheses):

> --- a/arch/arm/mach-ixp4xx/include/mach/io.h
>
> -#define ioport_map(port, nr) ((void __iomem*)(port + PIO_OFFSET))
^^^^
--
Krzysztof Halasa

Industrial Research Institute for Automation and Measurements PIAP
Al. Jerozolimskie 202, 02-486 Warsaw, Poland