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authorMark Fasheh <mfasheh@suse.com>2008-04-10 13:55:21 -0700
committerJonathan Corbet <corbet@lwn.net>2008-04-11 13:21:14 -0600
commit14dadf1d5eb5bea2dd115852cfee880505c1c169 (patch)
tree03a1060a8191483dbd93964a6909f5c103d75ce4 /Documentation/spinlocks.txt
parentd396c5f158547e50c2b78bc984cb4a72d76e969b (diff)
downloadlinux-linaro-stable-14dadf1d5eb5bea2dd115852cfee880505c1c169.tar.gz
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 <mfasheh@suse.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/spinlocks.txt')
-rw-r--r--Documentation/spinlocks.txt22
1 files changed, 22 insertions, 0 deletions
diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt
index 471e75389778..619699dde593 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.