From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Christoph Hellwig <hch@lst.de>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] block: fix blk_queue_alignment_offset
Date: Sun, 19 Jul 2009 22:19:55 -0400 [thread overview]
Message-ID: <yq1ab30jdtg.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <20090719223649.GA32719@lst.de> (Christoph Hellwig's message of "Mon, 20 Jul 2009 00:36:49 +0200")
>>>>> "hch" == Christoph Hellwig <hch@lst.de> writes:
hch> We need to mask out bits inside the logical block, not outside of
hch> it, otherwise we'll always get a 0 alignment_offset.
The alignment_offset only makes sense if physical_block_size >
logical_block_size. For instance (63 * 512) & (4096 - 1) = 3584.
Your patch would yield 28672 = 4096 * 7 and that's incorrect; LBA 63 is
not aligned on a 4KB boundary...
--
Martin K. Petersen Oracle Linux Engineering
prev parent reply other threads:[~2009-07-20 2:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-19 22:36 Christoph Hellwig
2009-07-20 2:19 ` Martin K. Petersen [this message]
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