Re: [PATCH 1/3 v2] iscsi iser: remove DMA alignment restriction

[Erez Zilber <erezz@Voltaire.COM>]

Pete Wyckoff wrote:
> Thanks to James pointing out the problems with the BLK_BOUNCE_ANY
> for IB devices, this revised patch contains only the DMA alignment
> fix for iSER.
>
> Mike, can you take care of this and the other two patches in the
> series:
>
>     [PATCH 2/3] iscsi iser: increase max_sectors
>     [PATCH 3/3] iscsi iser: increase sg_tablesize
>
> 		-- Pete
>
>
> From 255e73b67ec1458af18395981fddebdc958e8fe9 Mon Sep 17 00:00:00 2001
> From: Pete Wyckoff <pw@osc.edu>
> Date: Thu, 14 Feb 2008 16:09:27 -0500
> Subject: [PATCH] iscsi iser: remove DMA alignment restriction
>
> iscsi_iser does not require any particular DMA aligement
> requirement.  Add a slave_configure function to set the alignment
> to zero, allowing the use of direct IO from arbitrary offsets
> within a page.
>   

We had a long discussion about it, and I'm ok with this patch. However,
I would change the description:

iSER has DMA alignment requirements that are too complex to express with
q->dma_alignment. Therefore, if necessary, bouncing should be done by
the iSER driver. Add a slave_configure function to set the alignment to
zero, allowing the use of direct IO from arbitrary offsets within a page.

Erez