From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id E72135F0001 for ; Tue, 14 Apr 2009 02:21:36 -0400 (EDT) Received: from mt1.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n3E6Ltke021105 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 14 Apr 2009 15:21:55 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 5F35D45DE56 for ; Tue, 14 Apr 2009 15:21:55 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 883C445DE58 for ; Tue, 14 Apr 2009 15:21:54 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id A57861DB803E for ; Tue, 14 Apr 2009 15:21:53 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.249.87.107]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 1CEEF1DB8040 for ; Tue, 14 Apr 2009 15:21:53 +0900 (JST) From: KOSAKI Motohiro Subject: [RFC][PATCH v3 5/6] don't use bio-map in read() path In-Reply-To: <20090414151204.C647.A69D9226@jp.fujitsu.com> References: <20090414151204.C647.A69D9226@jp.fujitsu.com> Message-Id: <20090414152020.C656.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 14 Apr 2009 15:21:51 +0900 (JST) Sender: owner-linux-mm@kvack.org To: LKML Cc: kosaki.motohiro@jp.fujitsu.com, Linus Torvalds , Andrew Morton , Nick Piggin , Andrea Arcangeli , Jeff Moyer , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, FUJITA Tomonori , Jens Axboe , James Bottomley List-ID: Who know proper fixing way? ================= Subject: [Untested][RFC][PATCH] don't use bio-map in read() path __bio_map_user_iov() has wrong usage of get_user_pages_fast(). it doesn't have prevent fork mechanism. then, it sould be used read-side (memory to device transfer) gup only. This patch is obviously temporally fix. we can implement fork safe bio_map_user() the future... Signed-off-by: KOSAKI Motohiro Cc: FUJITA Tomonori Cc: Jens Axboe Cc: James Bottomley --- block/blk-map.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Index: b/block/blk-map.c =================================================================== --- a/block/blk-map.c 2009-02-21 16:53:21.000000000 +0900 +++ b/block/blk-map.c 2009-04-12 23:36:32.000000000 +0900 @@ -55,7 +55,7 @@ static int __blk_rq_map_user(struct requ * direct dma. else, set up kernel bounce buffers */ uaddr = (unsigned long) ubuf; - if (blk_rq_aligned(q, ubuf, len) && !map_data) + if (blk_rq_aligned(q, ubuf, len) && !map_data && !reading) bio = bio_map_user(q, NULL, uaddr, len, reading, gfp_mask); else bio = bio_copy_user(q, map_data, uaddr, len, reading, gfp_mask); @@ -208,7 +208,7 @@ int blk_rq_map_user_iov(struct request_q } } - if (unaligned || (q->dma_pad_mask & len) || map_data) + if (unaligned || (q->dma_pad_mask & len) || map_data || read) bio = bio_copy_user_iov(q, map_data, iov, iov_count, read, gfp_mask); else -- 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