From 017f021c7e5fe3f82ccc5cbb7b1750e66e00f527 Mon Sep 17 00:00:00 2001 From: "Ed L. Cashin" Date: Sun, 15 Jul 2007 23:41:50 -0700 Subject: 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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/spinlocks.txt | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) (limited to 'Documentation/spinlocks.txt') diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt index a661d684768..471e7538977 100644 --- a/Documentation/spinlocks.txt +++ b/Documentation/spinlocks.txt @@ -1,7 +1,12 @@ -UPDATE March 21 2005 Amit Gud +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. ----------------------- -- cgit v1.2.3