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    SubjectRE: [PATCH] [scsi] Remove __GFP_DMA
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    The 31 bit limit for some of these cards is a problem, we currently only
    do __GFP_DMA for bounce buffer sg elements allocated for user supplied
    references in ioctls.

    I figure we should be using pci_alloc_consistent calls for these
    allocations to more accurately acquire memory within the 31 bit limit if
    necessary, we could switch to these to remove the need for the __GFP_DMA
    flag in the aacraid driver?

    -- Mark

    -----Original Message-----
    From: linux-scsi-owner@vger.kernel.org
    [mailto:linux-scsi-owner@vger.kernel.org] On Behalf Of James Bottomley
    Sent: Wednesday, May 23, 2007 11:18 AM
    To: Aubrey Li
    Cc: Christoph Lameter; Bernhard Walle; linux-scsi@vger.kernel.org;
    Andrew Morton; linux-kernel@vger.kernel.org
    Subject: Re: [PATCH] [scsi] Remove __GFP_DMA

    On Wed, 2007-05-23 at 10:41 +0800, Aubrey Li wrote:
    > On 5/23/07, Christoph Lameter <clameter@sgi.com> wrote:
    > > On Mon, 21 May 2007, Bernhard Walle wrote:
    > >
    > > > [PATCH] [scsi] Remove __GFP_DMA
    > > >
    > > > After 821de3a27bf33f11ec878562577c586cd5f83c64, it's not necessary
    to alloate a
    > > > DMA buffer any more in sd.c.
    > > >
    > > > Signed-off-by: Bernhard Walle <bwalle@suse.de>
    > >
    > > Great that avoids a DMA kmalloc slab. Any other GFP_DMAs left in the
    scsi
    > > layer?
    > >
    > > Acked-by: Christoph Lameter <clameter@sgi.com>
    >
    > Yes, here is another patch

    I'll defer to Mark on this one. However, please remember that you can't
    just blindly remove GFP_DMA ... there are some cards which require it.

    Aacraid is one example ... it has a set of cards that can only DMA to 31
    bits. For them, the GFP_DMA is necessary: The allocation in question
    is a scatterlist, which must be within the device DMA mask.

    James


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