From 14dadf1d5eb5bea2dd115852cfee880505c1c169 Mon Sep 17 00:00:00 2001 From: Mark Fasheh Date: Thu, 10 Apr 2008 13:55:21 -0700 Subject: [PATCH] Add additional examples in Documentation/spinlocks.txt Checkpatch will throw an error if code doesn't use the correct initializers for static spinlocks: ERROR: Use of SPIN_LOCK_UNLOCKED is deprecated: see Documentation/spinlocks.txt This is fine, but Documentation/spinlocks.txt isn't very clear on how to _use_ the new initializers for static variables. To save people time in the future, I added two small examples of how to fix old-style static initializers to be more lockdep friendly. Signed-off-by: Mark Fasheh Signed-off-by: Jonathan Corbet --- Documentation/spinlocks.txt | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt index 471e7538977..619699dde59 100644 --- a/Documentation/spinlocks.txt +++ b/Documentation/spinlocks.txt @@ -5,6 +5,28 @@ Please use DEFINE_SPINLOCK()/DEFINE_RWLOCK() or __SPIN_LOCK_UNLOCKED()/__RW_LOCK_UNLOCKED() as appropriate for static initialization. +Most of the time, you can simply turn: + + static spinlock_t xxx_lock = SPIN_LOCK_UNLOCKED; + +into: + + static DEFINE_SPINLOCK(xxx_lock); + +Static structure member variables go from: + + struct foo bar { + .lock = SPIN_LOCK_UNLOCKED; + }; + +to: + + struct foo bar { + .lock = __SPIN_LOCK_UNLOCKED(bar.lock); + }; + +Declaration of static rw_locks undergo a similar transformation. + Dynamic initialization, when necessary, may be performed as demonstrated below.