Fix RCU_GP_CTR_BIT

> > You lost me on this one:
> >
> >     sizeof(long) << 2 = 0x10
> >
> > I could believe the following (run on a 32-bit machine):
> >
> >     1 << (sizeof(long) * 8 - 1) = 0x80000000
> >
> > Or, if you were wanting to use a bit halfway up the word, perhaps this:
> >
> >     1 << (sizeof(long) * 4 - 1) = 0x8000
> >
> > Or am I confused?
>
> Well, I am at least partly confused.  You were wanting a low-order bit,
> so you want to lose the "- 1" above.  Here are some of the possibilities:
>
>       sizeof(long) = 0x4
>       sizeof(long) << 2 = 0x10
>       1 << (sizeof(long) * 8 - 1) = 0x80000000
>       1 << (sizeof(long) * 4) = 0x10000
>       1 << (sizeof(long) * 4 - 1) = 0x8000
>       1 << (sizeof(long) * 2) = 0x100
>       1 << (sizeof(long) * 2 - 1) = 0x80
>
> My guess is that 1 << (sizeof(long) * 4) and 1 << (sizeof(long) * 2)
> are of the most interest.
>

Exactly. I'll change it to :

I somehow thought this define was used as a bit number rather than the
bit mask.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

diff --git a/urcu.h b/urcu.h
index 424980650474953be7c7e081ec0fe07f5e14d034..444d9cdba3346d987070dfa8fc68b78df4fe923f 100644 (file)
--- a/urcu.h
+++ b/urcu.h
@@ -165,9 +165,9 @@ static inline void debug_yield_init(void)
  * The trick here is that RCU_GP_CTR_BIT must be a multiple of 8 so we can use a
  * full 8-bits, 16-bits or 32-bits bitmask for the lower order bits.
  */
-#define RCU_GP_COUNT           (1U << 0)
+#define RCU_GP_COUNT           (1UL << 0)
 /* Use the amount of bits equal to half of the architecture long size */
-#define RCU_GP_CTR_BIT         (sizeof(long) << 2)
+#define RCU_GP_CTR_BIT         (1UL << (sizeof(long) << 2))
 #define RCU_GP_CTR_NEST_MASK   (RCU_GP_CTR_BIT - 1)
 
 /*