diff options
Diffstat (limited to 'include/linux/compiler.h')
| -rw-r--r-- | include/linux/compiler.h | 24 |
1 files changed, 5 insertions, 19 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 793c0829e..668569844 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -17,7 +17,6 @@ # define __release(x) __context__(x,-1) # define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0) # define __percpu __attribute__((noderef, address_space(3))) -# define __pmem __attribute__((noderef, address_space(5))) #ifdef CONFIG_SPARSE_RCU_POINTER # define __rcu __attribute__((noderef, address_space(4))) #else /* CONFIG_SPARSE_RCU_POINTER */ @@ -45,7 +44,6 @@ extern void __chk_io_ptr(const volatile void __iomem *); # define __cond_lock(x,c) (c) # define __percpu # define __rcu -# define __pmem # define __private # define ACCESS_PRIVATE(p, member) ((p)->member) #endif /* __CHECKER__ */ @@ -304,23 +302,6 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s __u.__val; \ }) -/** - * smp_cond_acquire() - Spin wait for cond with ACQUIRE ordering - * @cond: boolean expression to wait for - * - * Equivalent to using smp_load_acquire() on the condition variable but employs - * the control dependency of the wait to reduce the barrier on many platforms. - * - * The control dependency provides a LOAD->STORE order, the additional RMB - * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order, - * aka. ACQUIRE. - */ -#define smp_cond_acquire(cond) do { \ - while (!(cond)) \ - cpu_relax(); \ - smp_rmb(); /* ctrl + rmb := acquire */ \ -} while (0) - #endif /* __KERNEL__ */ #endif /* __ASSEMBLY__ */ @@ -545,10 +526,15 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s * Similar to rcu_dereference(), but for situations where the pointed-to * object's lifetime is managed by something other than RCU. That * "something other" might be reference counting or simple immortality. + * + * The seemingly unused variable ___typecheck_p validates that @p is + * indeed a pointer type by using a pointer to typeof(*p) as the type. + * Taking a pointer to typeof(*p) again is needed in case p is void *. */ #define lockless_dereference(p) \ ({ \ typeof(p) _________p1 = READ_ONCE(p); \ + typeof(*(p)) *___typecheck_p __maybe_unused; \ smp_read_barrier_depends(); /* Dependency order vs. p above. */ \ (_________p1); \ }) |