From: David S. Miller Date: Wed, 18 Aug 2010 00:09:53 +0000 (-0700) Subject: sparc64: Fix rwsem constant bug leading to hangs. X-Git-Tag: v2.6.35.4~56 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e214c09dc0c3a34b543cbcbacd712c5ba1a1d76c;p=karo-tx-linux.git sparc64: Fix rwsem constant bug leading to hangs. [ Upstream commit ef201bebe5afc91a2b99b45dacc8c6dd88ca9e58 ] As noticed by Linus, it is critical that some of the rwsem constants be signed. Yet, hex constants are unsigned unless explicitly casted or negated. The most critical one is RWSEM_WAITING_BIAS. This bug was exacerbated by commit 424acaaeb3a3932d64a9b4bd59df6cf72c22d8f3 ("rwsem: wake queued readers when writer blocks on active read lock") Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/sparc/include/asm/rwsem-const.h b/arch/sparc/include/asm/rwsem-const.h index a303c9d64d84..e4c61a18bb28 100644 --- a/arch/sparc/include/asm/rwsem-const.h +++ b/arch/sparc/include/asm/rwsem-const.h @@ -5,7 +5,7 @@ #define RWSEM_UNLOCKED_VALUE 0x00000000 #define RWSEM_ACTIVE_BIAS 0x00000001 #define RWSEM_ACTIVE_MASK 0x0000ffff -#define RWSEM_WAITING_BIAS 0xffff0000 +#define RWSEM_WAITING_BIAS (-0x00010000) #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS #define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)