Introduce this_cpu_cmpxchg_double. this_cpu_cmpxchg_double() allows the comparision between two consecutive words and replaces them if there is a match. bool this_cpu_cmpxchg_double(pcp1, pcp2, old_word1, old_word2, new_word1, new_word2) this_cpu_cmpxchg_double does not return the old value (difficult since there are two words) but a boolean indicating if the operation was successful. The first percpu variable must be double word aligned! Signed-off-by: Christoph Lameter --- include/linux/percpu.h | 130 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 130 insertions(+) Index: linux-2.6/include/linux/percpu.h =================================================================== --- linux-2.6.orig/include/linux/percpu.h 2011-01-10 10:22:35.000000000 -0600 +++ linux-2.6/include/linux/percpu.h 2011-01-10 10:26:43.000000000 -0600 @@ -255,6 +255,29 @@ extern void __bad_size_call_parameter(vo pscr2_ret__; \ }) +/* + * Special handling for cmpxchg_double. cmpxchg_double is passed two + * percpu variables. The first has to be aligned to a double word + * boundary and the second has to follow directly thereafter. + */ +#define __pcpu_double_call_return_int(stem, pcp1, pcp2, ...) \ +({ \ + int ret__; \ + __verify_pcpu_ptr(&pcp1); \ + VM_BUG_ON((unsigned long)(&pcp1) % (2 * sizeof(pcp1))); \ + VM_BUG_ON((unsigned long)(&pcp2) != (unsigned long)(&pcp1) + sizeof(pcp1));\ + VM_BUG_ON(sizeof(pcp1) != sizeof(pcp2)); \ + switch(sizeof(pcp1)) { \ + case 1: ret__ = stem##1(pcp1, pcp2, __VA_ARGS__);break; \ + case 2: ret__ = stem##2(pcp1, pcp2, __VA_ARGS__);break; \ + case 4: ret__ = stem##4(pcp1, pcp2, __VA_ARGS__);break; \ + case 8: ret__ = stem##8(pcp1, pcp2, __VA_ARGS__);break; \ + default: \ + __bad_size_call_parameter();break; \ + } \ + ret__; \ +}) + #define __pcpu_size_call(stem, variable, ...) \ do { \ __verify_pcpu_ptr(&(variable)); \ @@ -318,6 +341,80 @@ do { \ # define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, (pcp)) #endif +/* + * cmpxchg_double replaces two adjacent scalars at once. The first two + * parameters are per cpu variables which have to be of the same size. + * A truth value is returned to indicate success or + * failure (since a double register result is difficult to handle). + * There is very limited hardware support for these operations. So only certain + * sizes may work. + */ +#define __this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \ +({ \ + int __ret = 0; \ + if (__this_cpu_read(pcp1) == (oval1) && \ + __this_cpu_read(pcp2) == (oval2)) { \ + __this_cpu_write(pcp1, (nval1)); \ + __this_cpu_write(pcp2, (nval2)); \ + __ret = 1; \ + } \ + (__ret); \ +}) + +#ifndef __this_cpu_cmpxchg_double +# ifndef __this_cpu_cmpxchg_double_1 +# define __this_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + __this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef __this_cpu_cmpxchg_double_2 +# define __this_cpu_cmpxchg_double_2(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + __this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef __this_cpu_cmpxchg_double_4 +# define __this_cpu_cmpxchg_double_4(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + __this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef __this_cpu_cmpxchg_double_8 +# define __this_cpu_cmpxchg_double_8(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + __this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# define __this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + __pcpu_double_call_return_int(__this_cpu_cmpxchg_double_, (pcp1), (pcp2) \ + oval1, oval2, nval1, nval2) +#endif + +#define _this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \ +({ \ + int ret__; \ + preempt_disable(); \ + ret__ = __this_cpu_generic_cmpxchg_double(pcp1, pcp2, \ + oval1, oval2, nval1, nval2); \ + preempt_enable(); \ + ret__; \ +}) + +#ifndef this_cpu_cmpxchg_double +# ifndef this_cpu_cmpxchg_double_1 +# define this_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + _this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef this_cpu_cmpxchg_double_2 +# define this_cpu_cmpxchg_double_2(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + _this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef this_cpu_cmpxchg_double_4 +# define this_cpu_cmpxchg_double_4(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + _this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef this_cpu_cmpxchg_double_8 +# define this_cpu_cmpxchg_double_8(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + _this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# define this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + __pcpu_double_call_return_int(this_cpu_cmpxchg_double_, (pcp1), (pcp2), \ + oval1, oval2, nval1, nval2) +#endif + #define _this_cpu_generic_to_op(pcp, val, op) \ do { \ preempt_disable(); \ @@ -823,4 +920,37 @@ do { \ __pcpu_size_call_return2(irqsafe_cpu_cmpxchg_, (pcp), oval, nval) #endif +#define irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \ +({ \ + int ret__; \ + unsigned long flags; \ + local_irq_save(flags); \ + ret__ = __this_cpu_generic_cmpxchg_double(pcp1, pcp2, \ + oval1, oval2, nval1, nval2); \ + local_irq_restore(flags); \ + ret__; \ +}) + +#ifndef irqsafe_cpu_cmpxchg_double +# ifndef irqsafe_cpu_cmpxchg_double_1 +# define irqsafe_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef irqsafe_cpu_cmpxchg_double_2 +# define irqsafe_cpu_cmpxchg_double_2(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef irqsafe_cpu_cmpxchg_double_4 +# define irqsafe_cpu_cmpxchg_double_4(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# ifndef irqsafe_cpu_cmpxchg_double_8 +# define irqsafe_cpu_cmpxchg_double_8(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) +# endif +# define irqsafe_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \ + __pcpu_double_call_return_int(irqsafe_cpu_cmpxchg_double_, (pcp1), (pcp2), \ + oval1, oval2, nval1, nval2) +#endif + #endif /* __LINUX_PERCPU_H */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/