From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: [PATCH] Fix accesses at LBA28 boundary (old bug, but nasty) (v2) Date: Wed, 07 Apr 2010 13:52:08 -0400 Message-ID: <4BBCC648.30807@teksavvy.com> References: <4BBBB975.7000203@teksavvy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from ironport2-out.teksavvy.com ([206.248.154.181]:56274 "EHLO ironport2-out.pppoe.ca" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751401Ab0DGRwM (ORCPT ); Wed, 7 Apr 2010 13:52:12 -0400 In-Reply-To: <4BBBB975.7000203@teksavvy.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: IDE/ATA development list , Jeff Garzik , Tejun Heo , Alan Cox , Ric Wheeler Most drives from Seagate, Hitachi, and possibly other brands, do not allow LBA28 access to sector number 0x0fffffff (2^28 - 1). So instead use LBA48 for such accesses. This bug could bite a lot of systems, especially when the user has taken care to align partitions to 4KB boundaries. On misaligned systems, it is less likely to be encountered, since a 4KB read would end at 0x10000000 rather than at 0x0fffffff. Signed-off-by: Mark Lord --- Reposting with the pre-existing (u64) cast removed. --- linux-2.6.34-rc3/include/linux/ata.h 2010-03-30 12:24:39.000000000 -0400 +++ linux/include/linux/ata.h 2010-04-06 18:39:41.167702612 -0400 @@ -1025,8 +1025,8 @@ static inline int lba_28_ok(u64 block, u32 n_block) { - /* check the ending block number */ - return ((block + n_block) < ((u64)1 << 28)) && (n_block <= 256); + /* check the ending block number: must be LESS THAN 0x0fffffff */ + return ((block + n_block) < ((1 << 28) - 1)) && (n_block <= 256); } static inline int lba_48_ok(u64 block, u32 n_block)