From: Jens Axboe <jens.axboe@oracle.com>
To: Benny Halevy <bhalevy@panasas.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH 8/12] x86-64: update iommu/dma mapping functions to sg helpers
Date: Thu, 10 May 2007 23:38:39 +0200 [thread overview]
Message-ID: <20070510213839.GZ4163@kernel.dk> (raw)
In-Reply-To: <464322BC.50101@panasas.com>
On Thu, May 10 2007, Benny Halevy wrote:
> Jens Axboe wrote:
> <snip>
> > @@ -323,13 +324,17 @@ static int __dma_map_cont(struct scatterlist *sg, int start, int stopat,
> > {
> > unsigned long iommu_start = alloc_iommu(pages);
> > unsigned long iommu_page = iommu_start;
> > - int i;
> > + struct scatterlist *s;
> > + int i, nelems;
> >
> > if (iommu_start == -1)
> > return -1;
> > +
> > + nelems = stopat - start;
> > + while (start--)
> > + sg = sg_next(sg);
>
> Ouch. This will suck if we merge many times in a long list.
> How about keeping and passing start as a struct scatterlist * rather
> than an index? (see attached example, (compiles, bu untested though)
It will suck indeed, I like your patch! I'll review and incorporate.
Your other points are good, noted.
--
Jens Axboe
next prev parent reply other threads:[~2007-05-10 22:00 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-10 11:40 [PATCH 0/12] Chaining sg lists for bio IO commands v4 Jens Axboe
2007-05-10 11:40 ` [PATCH 1/12] crypto: don't pollute the global namespace with sg_next() Jens Axboe
2007-05-10 13:55 ` Benny Halevy
2007-05-10 21:37 ` Jens Axboe
2007-05-11 5:20 ` Benny Halevy
2007-05-12 2:34 ` Herbert Xu
2007-05-10 11:40 ` [PATCH 2/12] Add sg helpers for iterating over a scatterlist table Jens Axboe
2007-05-10 11:40 ` [PATCH 3/12] libata: convert to using sg helpers Jens Axboe
2007-05-10 11:40 ` [PATCH 4/12] block: " Jens Axboe
2007-05-10 11:40 ` [PATCH 5/12] scsi: " Jens Axboe
2007-05-10 11:40 ` [PATCH 6/12] i386 dma_map_sg: " Jens Axboe
2007-05-10 11:40 ` [PATCH 7/12] i386 sg: add support for chaining scatterlists Jens Axboe
2007-05-10 13:00 ` Satyam Sharma
2007-05-10 13:23 ` Satyam Sharma
2007-05-10 11:40 ` [PATCH 8/12] x86-64: update iommu/dma mapping functions to sg helpers Jens Axboe
2007-05-10 13:48 ` Benny Halevy
2007-05-10 21:38 ` Jens Axboe [this message]
2007-05-21 6:32 ` Jens Axboe
2007-05-21 7:09 ` Benny Halevy
2007-05-21 7:13 ` Jens Axboe
2007-05-10 11:40 ` [PATCH 9/12] x86-64: enable sg chaining Jens Axboe
2007-05-10 11:40 ` [PATCH 10/12] scsi: simplify scsi_free_sgtable() Jens Axboe
2007-05-10 11:40 ` [PATCH 11/12] SCSI: support for allocating large scatterlists Jens Axboe
2007-05-10 11:40 ` [PATCH 12/12] ll_rw_blk: temporarily enable max_segments tweaking Jens Axboe
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