linux-kernel - Re: [KJ] remove SPIN_LOCK

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <3b44d3fb0704102109g380bbb04v3579a94e1b6dabe1@mail.gmail.com>
Date:	Wed, 11 Apr 2007 09:39:16 +0530
From:	"Milind Arun Choudhary" <milindchoudhary@...il.com>
To:	"Matthew Wilcox" <matthew@....cx>
Cc:	"Robert P. J. Day" <rpjday@...dspring.com>,
	kernelnewbies@...linux.org, kernel-janitors@...ts.osdl.org,
	"Roland Dreier" <rdreier@...co.com>,
	"Jan Engelhardt" <jengelh@...ux01.gwdg.de>,
	linux-kernel@...r.kernel.org
Subject: Re: [KJ] remove SPIN_LOCK_UNLOCKED

On 4/11/07, Matthew Wilcox <matthew@....cx> wrote:
> On Tue, Apr 10, 2007 at 05:45:07PM -0400, Robert P. J. Day wrote:
> > that works fine if you're defining a single spinlock, but what do you
> > do in cases like this:
> >
> > arch/sparc/lib/atomic32.c:      [0 ... (ATOMIC_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED
> >
> > that is, when you're assigning an array of them?  you still need some
> > kind of generic, unnamed spinlock in those circumstances, no?
>
> That's a special case for architecture-only code.  It's not to be used
> by drivers.
as per my understanding, [which i should have keyed in earlier]
different places where SPIN_LOCK_UNLOCKED currently appears are

1. static spinlock_t foobar = SPIN_LOCK_UNLOCKED;
needs to be replaced bye DEFINE_SPINLOCK

e.g  linux-core/drm_memory_debug.h
-static spinlock_t drm_mem_lock = SPIN_LOCK_UNLOCKED;
+static DEFINE_SPINLOCK(drm_mem_lock);

there are very few occurrences left in the tree i see

2. allocating a data structure dynamically
& initializing the spinlock embedded within

use spin_lock_init()
e.g   linux-core/via_dmablit.c

-               blitq->blit_lock = SPIN_LOCK_UNLOCKED;
+               spin_lock_init(&blitq->blit_lock);

3. static initialization of structure members
struct foo bar ={
.
.
.
.lock = SPIN_LOCK_UNLOCKED,
.
}
use
struct foo bar ={
.
.
.
.lock = __SPIN_LOCK_UNLOCKED(bar.lock),
.
}

e.g arch/i386/kernel/traps.c
-		.lock =			SPIN_LOCK_UNLOCKED,
+		.lock =			__SPIN_LOCK_UNLOCKED(die.lock),

plenty of these are still there
may be some patches queued


4. arrays of spinlocks
e.g arch/cris/arch-v32/kernel/smp.c

-spinlock_t cris_atomic_locks[] = { [0 ... LOCK_COUNT - 1] =
SPIN_LOCK_UNLOCKED};
+raw_spinlock_t cris_atomic_locks[] = { [0 ... LOCK_COUNT - 1] =
__RAW_SPIN_LOCK_UNLOCKED};


my question is still there in the original post
about spin_lock_init()

CMIIW
Refer:
http://lkml.org/lkml/2005/6/20/47
http://lkml.org/lkml/2007/1/16/90
http://lists.openwall.net/linux-kernel/2007/02/01/258
-- 
Milind Arun Choudhary
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/