From: Pavel Emelianov <xemul@sw.ru>
To: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@redhat.com>,
Arjan van de Ven <arjan@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH] Lockdep treats down_write_trylock like regular down_write
Date: Mon, 09 Apr 2007 13:56:44 +0400 [thread overview]
Message-ID: <461A0DDC.5060709@sw.ru> (raw)
[-- Attachment #1: Type: text/plain, Size: 282 bytes --]
This causes constructions like
down_write(&mm1->mmap_sem);
if (down_write_trylock(&mm2->mmap_sem)) {
...
up_write(&mm2->mmap_sem);
}
up_write(&mm1->mmap_sem);
generate a lockdep warning about circular locking dependence.
Call rwsem_acquire() with trylock set to 1.
[-- Attachment #2: diff-lockdep-rwsem-trylock --]
[-- Type: text/plain, Size: 356 bytes --]
--- ./kernel/rwsem.c.pbonrem 2007-03-06 19:09:50.000000000 +0300
+++ ./kernel/rwsem.c 2007-04-06 14:02:18.000000000 +0400
@@ -60,7 +60,7 @@ int down_write_trylock(struct rw_semapho
int ret = __down_write_trylock(sem);
if (ret == 1)
- rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+ rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_);
return ret;
}
next reply other threads:[~2007-04-09 9:52 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-09 9:56 Pavel Emelianov [this message]
2007-04-09 15:09 ` [PATCH] Lockdep treats down_write_trylock like regular down_write Arjan van de Ven
2007-04-10 7:37 ` Pavel Emelianov
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