From: Joerg Roedel <joro@8bytes.org>
To: Mark Hounschell <markh@compro.net>
Cc: iommu@lists.linux-foundation.org, Hannes Reinecke <hare@suse.de>,
"linux-scsi@vger.kernel.org >> SCSI development list"
<linux-scsi@vger.kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: BUG: SCSI aic7xxx driver and AMD IOMMU
Date: Thu, 26 Mar 2015 16:52:49 +0100 [thread overview]
Message-ID: <20150326155248.GW4441@8bytes.org> (raw)
In-Reply-To: <55141E87.8040506@compro.net>
Hi Mark,
On Thu, Mar 26, 2015 at 10:58:15AM -0400, Mark Hounschell wrote:
> Sorry but CMA was still badly broken. I have a patch below that works.
In which way is it broken? What happens when you try to allocate memory
with dma_alloc_coherent?
> I've tested it with small (no CMA) and large (with CMA) dma's using
> dma_alloc_coherent. The patch below is just the "git diff" from your
> cloned tree piped to a file then copied into this email. If you require
> an official patch I can send one. Just let me know.
The main differences I can spot are that you change the order (first
CMA, then buddy) and you manually align the input size. I can see the
reason for the later, but why does CMA need to be tried first?
> Also, in my opinion, this CMA thing is clearly a BUG not a feature
> request. The AMD iommu clearly breaks CMA. I feel what ever fix
> you are happy with should be back ported to stable.
It is not a BUG, the interface definition for dma_alloc_coherent does
not specify that it can allocate infinite amounts of memory. So this
patch does not qualify for stable.
Joerg
next prev parent reply other threads:[~2015-03-26 15:52 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-16 14:34 BUG: SCSI aic7xxx driver and AMD IOMMU Mark Hounschell
[not found] ` <54E1FFFA.1060403-n2QNKt385d+sTnJN9+BGXg@public.gmane.org>
2015-03-03 19:36 ` Mark Hounschell
2015-03-23 15:03 ` Joerg Roedel
[not found] ` <20150323150304.GQ4441-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2015-03-24 11:57 ` Mark Hounschell
2015-03-25 13:59 ` Joerg Roedel
[not found] ` <20150325135937.GR4441-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2015-03-25 15:13 ` Joerg Roedel
2015-03-25 16:36 ` Mark Hounschell
[not found] ` <5512E412.9040807-n2QNKt385d+sTnJN9+BGXg@public.gmane.org>
2015-03-26 12:45 ` Joerg Roedel
2015-03-26 14:58 ` Mark Hounschell
2015-03-26 15:52 ` Joerg Roedel [this message]
[not found] ` <20150326155248.GW4441-zLv9SwRftAIdnm+yROfE0A@public.gmane.org>
2015-03-26 17:09 ` Mark Hounschell
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