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author | 2017-12-16 22:11:55 -0500 | |
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committer | 2017-12-16 22:11:55 -0500 | |
commit | c30abd5e40dd863f88e26be09b6ce949145a630a (patch) | |
tree | 5b25362084308502a336d8da26b8dc7430d7c812 /tools/include/linux/compiler.h | |
parent | net: phy: broadcom: Add entry for 5395 switch PHYs (diff) | |
parent | Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma (diff) | |
download | wireguard-linux-c30abd5e40dd863f88e26be09b6ce949145a630a.tar.xz wireguard-linux-c30abd5e40dd863f88e26be09b6ce949145a630a.zip |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Three sets of overlapping changes, two in the packet scheduler
and one in the meson-gxl PHY driver.
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'tools/include/linux/compiler.h')
-rw-r--r-- | tools/include/linux/compiler.h | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h index 07fd03c74a77..04e32f965ad7 100644 --- a/tools/include/linux/compiler.h +++ b/tools/include/linux/compiler.h @@ -84,8 +84,6 @@ #define uninitialized_var(x) x = *(&(x)) -#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x)) - #include <linux/types.h> /* @@ -135,20 +133,19 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s /* * Prevent the compiler from merging or refetching reads or writes. The * compiler is also forbidden from reordering successive instances of - * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the - * compiler is aware of some particular ordering. One way to make the - * compiler aware of ordering is to put the two invocations of READ_ONCE, - * WRITE_ONCE or ACCESS_ONCE() in different C statements. + * READ_ONCE and WRITE_ONCE, but only when the compiler is aware of some + * particular ordering. One way to make the compiler aware of ordering is to + * put the two invocations of READ_ONCE or WRITE_ONCE in different C + * statements. * - * In contrast to ACCESS_ONCE these two macros will also work on aggregate - * data types like structs or unions. If the size of the accessed data - * type exceeds the word size of the machine (e.g., 32 bits or 64 bits) - * READ_ONCE() and WRITE_ONCE() will fall back to memcpy and print a - * compile-time warning. + * These two macros will also work on aggregate data types like structs or + * unions. If the size of the accessed data type exceeds the word size of + * the machine (e.g., 32 bits or 64 bits) READ_ONCE() and WRITE_ONCE() will + * fall back to memcpy and print a compile-time warning. * * Their two major use cases are: (1) Mediating communication between * process-level code and irq/NMI handlers, all running on the same CPU, - * and (2) Ensuring that the compiler does not fold, spindle, or otherwise + * and (2) Ensuring that the compiler does not fold, spindle, or otherwise * mutilate accesses that either do not require ordering or that interact * with an explicit memory barrier or atomic instruction that provides the * required ordering. |