From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: dio_get_page() lockdep complaints From: Peter Zijlstra In-Reply-To: <1194857152.972.5.camel@localhost> References: <20070419073828.GB20928@kernel.dk> <1194627742.6289.175.camel@twins> <4734992C.7000408@oracle.com> <1194630300.7459.65.camel@heimdal.trondhjem.org> <1194810546.6098.6.camel@lappy> <1194857152.972.5.camel@localhost> Content-Type: text/plain Date: Mon, 12 Nov 2007 10:27:22 +0100 Message-Id: <1194859642.7179.1.camel@twins> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: schwidefsky@de.ibm.com Cc: Trond Myklebust , Zach Brown , Jens Axboe , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-aio@kvack.org, Chris Mason , linux-mm , Hugh Dickins , Linus Torvalds List-ID: On Mon, 2007-11-12 at 09:45 +0100, Martin Schwidefsky wrote: > On Sun, 2007-11-11 at 20:49 +0100, Peter Zijlstra wrote: > > Right, which gets us into all kinds of trouble because some sites need > > mmap_sem to resolve some races, notably s390 31-bit and shm. > > You are refering to the mmap_sem use in compat_linux.c:do_mmap2, aren't > you? That check for adresses > 2GB after the call to do_mmap_pgoff can > be removed since arch_get_unmapped_area already checks against > TASK_SIZE. The result of the do_mmap_pgoff call will never be out of > range. This check is a left-over from the early days of the s390 compat > code. Correct, that is the one I was referring to. Thanks for the explanation, I'll clean it up when I take this patch forward. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org