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From: Roel Kluin <roel.kluin@gmail.com>
To: ralf@linux-mips.org
Cc: linux-mips@linux-mips.org
Subject: [PATCH] MIPS: unsigned result is always greater than 0
Date: Fri, 02 Jan 2009 16:09:59 +0100	[thread overview]
Message-ID: <495E2E47.6080605@gmail.com> (raw)

unsigned result is always greater than 0

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
---
I cannot determine whether the same bug occurs as well in assembly.
Also shouldn't similar checks occur in atomic64_sub_return and in
atomic64_add_return for negative values of i?

diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h
index 1232be3..3cd07a9 100644
--- a/arch/mips/include/asm/atomic.h
+++ b/arch/mips/include/asm/atomic.h
@@ -296,9 +296,10 @@ static __inline__ int atomic_sub_if_positive(int i, atomic_t * v)
 
 		raw_local_irq_save(flags);
 		result = v->counter;
-		result -= i;
-		if (result >= 0)
+		if (i <= result) {
+			result -= i;
 			v->counter = result;
+		}
 		raw_local_irq_restore(flags);
 	}
 
@@ -677,9 +678,10 @@ static __inline__ long atomic64_sub_if_positive(long i, atomic64_t * v)
 
 		raw_local_irq_save(flags);
 		result = v->counter;
-		result -= i;
-		if (result >= 0)
+		if (i >= result) {
+			result -= i;
 			v->counter = result;
+		}
 		raw_local_irq_restore(flags);
 	}
 

             reply	other threads:[~2009-01-02 15:10 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-02 15:09 Roel Kluin [this message]
2009-01-06 21:46 ` [PATCH] MIPS: unsigned result is always greater than 0 David VomLehn (dvomlehn)
2009-01-06 21:46   ` David VomLehn (dvomlehn)
2009-01-12  1:26   ` Ralf Baechle

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