diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2014-12-16 12:25:38 +0100 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2014-12-16 12:25:38 +0100 |
commit | 8ab7913675726e5ae23b91221c0b5442d986d44a (patch) | |
tree | f2673dcb25e864cc87abe3f2d58db9bf9730f148 /Documentation/atomic_ops.txt | |
parent | 864b94adfcba752aa902ee34497bbe58b97aa8d3 (diff) | |
parent | 3a5dc1fafb016560315fe45bb4ef8bde259dd1bc (diff) |
Merge branch 'x86/vt-d' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu into x86/apic-picks
Required to apply Jiangs x86 irq handling rework without creating a
nightmare of conflicts.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'Documentation/atomic_ops.txt')
-rw-r--r-- | Documentation/atomic_ops.txt | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/Documentation/atomic_ops.txt b/Documentation/atomic_ops.txt index 68542fe13b85..183e41bdcb69 100644 --- a/Documentation/atomic_ops.txt +++ b/Documentation/atomic_ops.txt @@ -7,12 +7,13 @@ maintainers on how to implement atomic counter, bitops, and spinlock interfaces properly. - The atomic_t type should be defined as a signed integer. -Also, it should be made opaque such that any kind of cast to a normal -C integer type will fail. Something like the following should -suffice: + The atomic_t type should be defined as a signed integer and +the atomic_long_t type as a signed long integer. Also, they should +be made opaque such that any kind of cast to a normal C integer type +will fail. Something like the following should suffice: typedef struct { int counter; } atomic_t; + typedef struct { long counter; } atomic_long_t; Historically, counter has been declared volatile. This is now discouraged. See Documentation/volatile-considered-harmful.txt for the complete rationale. @@ -37,6 +38,9 @@ initializer is used before runtime. If the initializer is used at runtime, a proper implicit or explicit read memory barrier is needed before reading the value with atomic_read from another thread. +As with all of the atomic_ interfaces, replace the leading "atomic_" +with "atomic_long_" to operate on atomic_long_t. + The second interface can be used at runtime, as in: struct foo { atomic_t counter; }; |