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| author | Ed L. Cashin <ecashin@coraid.com> | 2007-07-16 08:41:50 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-16 18:05:52 +0200 |
| commit | 017f021c7e5fe3f82ccc5cbb7b1750e66e00f527 (patch) | |
| tree | 755a3f0f15a4adc1254ebb2ed1497afcf406ba55 /Documentation/spinlocks.txt | |
| parent | serial: remove termios checks from various old char serial drivers (diff) | |
| download | linux-017f021c7e5fe3f82ccc5cbb7b1750e66e00f527.tar.xz linux-017f021c7e5fe3f82ccc5cbb7b1750e66e00f527.zip | |
docs: static initialization of spinlocks is OK
Static initialization of spinlocks is preferable to dynamic initialization
when it is practical. This patch updates documentation for consistency
with comments in spinlock_types.h.
Signed-off-by: Ed L. Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/spinlocks.txt')
| -rw-r--r-- | Documentation/spinlocks.txt | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt index a661d684768e..471e75389778 100644 --- a/Documentation/spinlocks.txt +++ b/Documentation/spinlocks.txt @@ -1,7 +1,12 @@ -UPDATE March 21 2005 Amit Gud <gud@eth.net> +SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED defeat lockdep state tracking and +are hence deprecated. -Macros SPIN_LOCK_UNLOCKED and RW_LOCK_UNLOCKED are deprecated and will be -removed soon. So for any new code dynamic initialization should be used: +Please use DEFINE_SPINLOCK()/DEFINE_RWLOCK() or +__SPIN_LOCK_UNLOCKED()/__RW_LOCK_UNLOCKED() as appropriate for static +initialization. + +Dynamic initialization, when necessary, may be performed as +demonstrated below. spinlock_t xxx_lock; rwlock_t xxx_rw_lock; @@ -15,12 +20,9 @@ removed soon. So for any new code dynamic initialization should be used: module_init(xxx_init); -Reasons for deprecation - - it hurts automatic lock validators - - it becomes intrusive for the realtime preemption patches - -Following discussion is still valid, however, with the dynamic initialization -of spinlocks instead of static. +The following discussion is still valid, however, with the dynamic +initialization of spinlocks or with DEFINE_SPINLOCK, etc., used +instead of SPIN_LOCK_UNLOCKED. ----------------------- |