linux-kernel - [PATCH] Fix off-by-one errors in some pirq warnings

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Date:	Mon, 31 Mar 2008 04:27:30 +0200
From:	Björn Steinbrink <B.Steinbrink@....de>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Bob Tracy <rct@...s.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] Fix off-by-one errors in some pirq warnings

The conditions for the warnings simply ignored the fact that we later actually
use the original value minus 1, so the warning triggered even for valid values.

Signed-off-by: Björn Steinbrink <B.Steinbrink@....de>
---
[Sorry for the resend, I messed up the first one with a Reply-To instead
of an In-Reply-To header. I'll put on my brown paper bag...]

> In pirq_ali_{get,set} there's probably the same problem, but I can't
> really tell for sure, because pirq isn't used to index the array
> directly, and the comment above that functions tells me not to guess
> anything.

OK, so I made a guess anyway, the new condition at least makes more
sense to me.

 arch/x86/pci/irq.c |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/pci/irq.c b/arch/x86/pci/irq.c
index a871586..579745c 100644
--- a/arch/x86/pci/irq.c
+++ b/arch/x86/pci/irq.c
@@ -200,7 +200,7 @@ static int pirq_ali_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
 {
 	static const unsigned char irqmap[16] = { 0, 9, 3, 10, 4, 5, 7, 6, 1, 11, 0, 12, 0, 14, 0, 15 };
 
-	WARN_ON_ONCE(pirq >= 16);
+	WARN_ON_ONCE(pirq > 16);
 	return irqmap[read_config_nybble(router, 0x48, pirq-1)];
 }
 
@@ -209,7 +209,7 @@ static int pirq_ali_set(struct pci_dev *router, struct pci_dev *dev, int pirq, i
 	static const unsigned char irqmap[16] = { 0, 8, 0, 2, 4, 5, 7, 6, 0, 1, 3, 9, 11, 0, 13, 15 };
 	unsigned int val = irqmap[irq];
 
-	WARN_ON_ONCE(pirq >= 16);
+	WARN_ON_ONCE(pirq > 16);
 	if (val) {
 		write_config_nybble(router, 0x48, pirq-1, val);
 		return 1;
@@ -260,7 +260,7 @@ static int pirq_via586_get(struct pci_dev *router, struct pci_dev *dev, int pirq
 {
 	static const unsigned int pirqmap[5] = { 3, 2, 5, 1, 1 };
 
-	WARN_ON_ONCE(pirq >= 5);
+	WARN_ON_ONCE(pirq > 5);
 	return read_config_nybble(router, 0x55, pirqmap[pirq-1]);
 }
 
@@ -268,7 +268,7 @@ static int pirq_via586_set(struct pci_dev *router, struct pci_dev *dev, int pirq
 {
 	static const unsigned int pirqmap[5] = { 3, 2, 5, 1, 1 };
 
-	WARN_ON_ONCE(pirq >= 5);
+	WARN_ON_ONCE(pirq > 5);
 	write_config_nybble(router, 0x55, pirqmap[pirq-1], irq);
 	return 1;
 }
@@ -282,7 +282,7 @@ static int pirq_ite_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
 {
 	static const unsigned char pirqmap[4] = { 1, 0, 2, 3 };
 
-	WARN_ON_ONCE(pirq >= 4);
+	WARN_ON_ONCE(pirq > 4);
 	return read_config_nybble(router,0x43, pirqmap[pirq-1]);
 }
 
@@ -290,7 +290,7 @@ static int pirq_ite_set(struct pci_dev *router, struct pci_dev *dev, int pirq, i
 {
 	static const unsigned char pirqmap[4] = { 1, 0, 2, 3 };
 
-	WARN_ON_ONCE(pirq >= 4);
+	WARN_ON_ONCE(pirq > 4);
 	write_config_nybble(router, 0x43, pirqmap[pirq-1], irq);
 	return 1;
 }
-- 
1.5.5.rc2
--
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