On Tue, Jun 14, 2016 at 06:48:08PM -0400, Waiman Long wrote: > +++ b/arch/alpha/include/asm/rwsem.h > @@ -17,9 +17,9 @@ > #define RWSEM_UNLOCKED_VALUE 0x0000000000000000L > #define RWSEM_ACTIVE_BIAS 0x0000000000000001L > #define RWSEM_ACTIVE_MASK 0x00000000ffffffffL > -#define RWSEM_WAITING_BIAS (-0x0000000100000000L) > +#define RWSEM_WAITING_BIAS 0xc000000000000000L > #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS > -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + > RWSEM_ACTIVE_BIAS) > +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK)
> +++ b/arch/ia64/include/asm/rwsem.h > @@ -30,9 +30,9 @@ > #define RWSEM_UNLOCKED_VALUE __IA64_UL_CONST(0x0000000000000000) > #define RWSEM_ACTIVE_BIAS (1L) > #define RWSEM_ACTIVE_MASK (0xffffffffL) > -#define RWSEM_WAITING_BIAS (-0x100000000L) > +#define RWSEM_WAITING_BIAS (-(1L << 62)) > #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS > -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + > RWSEM_ACTIVE_BIAS) > +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK) > +++ b/arch/s390/include/asm/rwsem.h > @@ -42,9 +42,9 @@ > #define RWSEM_UNLOCKED_VALUE 0x0000000000000000L > #define RWSEM_ACTIVE_BIAS 0x0000000000000001L > #define RWSEM_ACTIVE_MASK 0x00000000ffffffffL > -#define RWSEM_WAITING_BIAS (-0x0000000100000000L) > +#define RWSEM_WAITING_BIAS 0xc000000000000000L > #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS > -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) > +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK) > +++ b/arch/x86/include/asm/rwsem.h > @@ -41,21 +41,23 @@ > > /* > * The bias values and the counter type limits the number of > - * potential readers/writers to 32767 for 32 bits and 2147483647 > - * for 64 bits. > + * potential writers to 16383 for 32 bits and 1073741823 for 64 bits. > + * The combined readers and writers can go up to 65534 for 32-bits and > + * 4294967294 for 64-bits. > */ > > #ifdef CONFIG_X86_64 > # define RWSEM_ACTIVE_MASK 0xffffffffL > +# define RWSEM_WAITING_BIAS (-(1L << 62)) > #else > # define RWSEM_ACTIVE_MASK 0x0000ffffL > +# define RWSEM_WAITING_BIAS (-(1L << 30)) > #endif > > #define RWSEM_UNLOCKED_VALUE 0x00000000L > #define RWSEM_ACTIVE_BIAS 0x00000001L > -#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1) > #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS > -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + > RWSEM_ACTIVE_BIAS) > +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK) > +++ b/include/asm-generic/rwsem.h > @@ -18,15 +18,16 @@ > */ > #ifdef CONFIG_64BIT > # define RWSEM_ACTIVE_MASK 0xffffffffL > +# define RWSEM_WAITING_BIAS (-(1L << 62)) > #else > # define RWSEM_ACTIVE_MASK 0x0000ffffL > +# define RWSEM_WAITING_BIAS (-(1L << 30)) > #endif > > #define RWSEM_UNLOCKED_VALUE 0x00000000L > #define RWSEM_ACTIVE_BIAS 0x00000001L > -#define RWSEM_WAITING_BIAS (-RWSEM_ACTIVE_MASK-1) > #define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS > -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + > RWSEM_ACTIVE_BIAS) > +#define RWSEM_ACTIVE_WRITE_BIAS (-RWSEM_ACTIVE_MASK) Can't we collapse all that? They all seem very similar.
