[PATCH 4/4] tty/serial: sh-sci: remove uneeded IS_ERR_OR_NULL calls
From: geert@linux-m68k.org (Geert Uytterhoeven)
Date: 2017-03-03 19:30:48
Also in:
linux-serial, lkml
Hi Uwe, On Fri, Mar 3, 2017 at 8:12 PM, Uwe Kleine-K?nig [off-list ref] wrote:
quoted hunk ↗ jump to hunk
On Fri, Mar 03, 2017 at 07:58:36PM +0100, Geert Uytterhoeven wrote:quoted
On Fri, Mar 3, 2017 at 3:22 PM, Richard Genoud [off-list ref] wrote:quoted
Since commit 1d267ea6539f ("serial: mctrl-gpio: simplify init routine"), the mctrl_gpio_to_gpiod() function can't return an error anymore. So, just testing for a NULL pointer is ok.If CONFIG_GPIOLIB=n, mctrl_gpio_to_gpiod() always returns ERR_PTR(-ENOSYS). That case should be handled correctly, too.The correct change to handle this is:diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 91e7dddbf72c..2f4cdd4e7b4f 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c@@ -3022,7 +3022,7 @@ static int sci_probe_single(struct platform_device *dev, return ret; sciport->gpios = mctrl_gpio_init(&sciport->port, 0); - if (IS_ERR(sciport->gpios) && PTR_ERR(sciport->gpios) != -ENOSYS) + if (IS_ERR(sciport->gpios)) return PTR_ERR(sciport->gpios);
Now the sh-sci driver fails to probe on legacy platforms where GPIOLIB=n. The check for -ENOSYS made it succeed before.
Then mctrl_gpio_to_gpiod isn't called. I don't have a machine to test
this, but I think currently this makes the machine barf to continue
here because with sciport->gpios = ERR_PTR(-ENOSYS) calling
mctrl_gpio_to_gpiod(sciport->gpios, ...)
is a bad idea.If sciport->gpios == ERR_PTR(-ENOSYS), CONFIG_GPIOLIB is not enabled, the feature is not available, and mctrl_gpio_to_gpiod() will not dereference the error pointer.
quoted
Perhaps mctrl_gpio_to_gpiod() should always return NULL if !CONFIG_GPIOLIB?No, mctrl_gpio_to_gpiod is right. You are only supposed to call it if mctrl_gpio_init succeeded.
Then I have to add checks for sciport->gpios == ERR_PTR(-ENOSYS)...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds