All of lore.kernel.org
 help / color / mirror / Atom feed
From: "Ed L. Cashin" <ecashin@coraid.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, Greg K-H <greg@kroah.com>
Subject: [PATCH 1/1] docs: static initialization of spinlocks is OK
Date: Tue, 3 Jul 2007 12:33:56 -0400	[thread overview]
Message-ID: <20070703163356.GF30089@coraid.com> (raw)
In-Reply-To: <<20070702213832.8864656c.akpm@linux-foundation.org>>

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>
---
 Documentation/spinlocks.txt |   20 +++++++++++---------
 1 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt
index a661d68..471e753 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.
 
 -----------------------
 
-- 
1.5.2.1

           reply	other threads:[~2007-07-03 16:35 UTC|newest]

Thread overview: expand[flat|nested]  mbox.gz  Atom feed
 [parent not found: <<20070702213832.8864656c.akpm@linux-foundation.org>]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20070703163356.GF30089@coraid.com \
    --to=ecashin@coraid.com \
    --cc=akpm@linux-foundation.org \
    --cc=greg@kroah.com \
    --cc=linux-kernel@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.