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Message-ID: <5e001ec1-d3f1-bcb8-7f30-a6301fd9930c@omp.ru>
Date: Sat, 6 Nov 2021 23:26:47 +0300
From: Sergey Shtylyov <s.shtylyov@....ru>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
"Rafael J. Wysocki" <rafael@...nel.org>
CC: <linux-kernel@...r.kernel.org>
Subject: [PATCH] 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")
Signed-off-by: Sergey Shtylyov <s.shtylyov@....ru>
---
The patch is against the 'driver-core-linus' branch of Greg Kroah-Hartman's
'driver-core.git' repo.
drivers/base/platform.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
Index: driver-core/drivers/base/platform.c
===================================================================
--- driver-core.orig/drivers/base/platform.c
+++ driver-core/drivers/base/platform.c
@@ -231,7 +231,8 @@ int platform_get_irq_optional(struct pla
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);
@@ -445,7 +446,8 @@ static int __platform_get_irq_byname(str
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;
}
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