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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2016-03-16 02:54:45 +0300 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2016-03-16 02:54:45 +0300 |
| commit | 245f0db0de926601353776085e6f6a4c974c5615 (patch) | |
| tree | b493e9e726f4a898041f7861d0df328aa1a348a1 /include/linux/compiler.h | |
| parent | 24672bdfb357b91bed0ea8d432241bf7bdefc8a8 (diff) | |
| parent | b562e44f507e863c6792946e4e1b1449fbbac85d (diff) | |
| download | linux-245f0db0de926601353776085e6f6a4c974c5615.tar.xz | |
Merge tag 'v4.5' into next
Merge with Linux 4.5 to get PROPERTY_ENTRY_INTEGER() that is needed to
fix pxa/raumfeld rotary encoder properties.
Diffstat (limited to 'include/linux/compiler.h')
| -rw-r--r-- | include/linux/compiler.h | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/include/linux/compiler.h b/include/linux/compiler.h index 4dac1036594f..48f5aab117ae 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -144,7 +144,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); */ #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) ) #define __trace_if(cond) \ - if (__builtin_constant_p((cond)) ? !!(cond) : \ + if (__builtin_constant_p(!!(cond)) ? !!(cond) : \ ({ \ int ______r; \ static struct ftrace_branch_data \ @@ -299,6 +299,23 @@ 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__ */ |