From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: libata .sg_tablesize: why always dividing by 2 ?
Date: Tue, 26 Feb 2008 13:52:03 +1100
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Cc: Jeff Garzik <jgarzik@pobox.com>, Tejun Heo <htejun@gmail.com>, Alan Cox <alan@redhat.com>, James Bottomley <James.Bottomley@HansenPartnership.com>, IDE/ATA development list <linux-ide@vger.kernel.org>


> The block layer uses seg_boundary_mask to ensure that we never have
> to split them again in the LLD.
> 
> A very long time ago, when I wrote the IDE DMA code, this was not the case.

Not good enough, still, because the boundaries can change due to the
iommu merging, thus the split must be re-done.

Ben.