platform: finally disallow IRQ0 in platform_get_irq() and its ilk

The commit a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is
invalid") only calls WARN() when IRQ0 is about to be returned, however
using IRQ0 is considered invalid (according to Linus) outside the arch/
code where it's used by the i8253 drivers. Many driver subsystems treat
0 specially (e.g. as an indication of the polling mode by libata), so
the users of platform_get_irq[_byname]() in them would have to filter
out IRQ0 explicitly and this (quite obviously) doesn't scale...
Let's finally get this straight and return -EINVAL instead of IRQ0!

Fixes: a85a6c86c25b ("driver core: platform: Clarify that IRQ 0 is invalid")
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/025679e1-1f0a-ae4b-4369-01164f691511@omp.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index b684157b7f2f9c01a147f4a51b1f4a33effcbace..5259f1f931873d380be0e1bca7f78b0f3a454d08 100644 (file)
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -231,7 +231,8 @@ int platform_get_irq_optional(struct platform_device *dev, unsigned int num)
 out_not_found:
        ret = -ENXIO;
 out:
-       WARN(ret == 0, "0 is an invalid IRQ number\n");
+       if (WARN(!ret, "0 is an invalid IRQ number\n"))
+               return -EINVAL;
        return ret;
 }
 EXPORT_SYMBOL_GPL(platform_get_irq_optional);
@@ -446,7 +447,8 @@ static int __platform_get_irq_byname(struct platform_device *dev,
 
        r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name);
        if (r) {
-               WARN(r->start == 0, "0 is an invalid IRQ number\n");
+               if (WARN(!r->start, "0 is an invalid IRQ number\n"))
+                       return -EINVAL;
                return r->start;
        }