From: konrad.wilk@oracle•com (Konrad Rzeszutek Wilk)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v5 1/1] iommu-api: Add map_sg/unmap_sg functions
Date: Mon, 11 Aug 2014 21:35:59 -0400 [thread overview]
Message-ID: <20140812013559.GA25121@laptop.dumpdata.com> (raw)
In-Reply-To: <1407797150-515-2-git-send-email-ohaugan@codeaurora.org>
On Mon, Aug 11, 2014 at 03:45:50PM -0700, Olav Haugan wrote:
> Mapping and unmapping are more often than not in the critical path.
> map_sg and unmap_sg allows IOMMU driver implementations to optimize
> the process of mapping and unmapping buffers into the IOMMU page tables.
>
> Instead of mapping a buffer one page at a time and requiring potentially
> expensive TLB operations for each page, this function allows the driver
> to map all pages in one go and defer TLB maintenance until after all
> pages have been mapped.
>
> Additionally, the mapping operation would be faster in general since
> clients does not have to keep calling map API over and over again for
> each physically contiguous chunk of memory that needs to be mapped to a
> virtually contiguous region.
>
> Signed-off-by: Olav Haugan <ohaugan@codeaurora•org>
Thank you for changing it this way.
.. snip..
> + for_each_sg(sg, s, nents, i) {
> + phys_addr_t phys = page_to_phys(sg_page(s));
> + size_t page_len = s->offset + s->length;
> +
> + ret = iommu_map(domain, iova + offset, phys, page_len,
> + prot);
> + if (ret) {
> + /* undo mappings already done */
> + iommu_unmap(domain, iova, offset);
Don't we want then to unmap all of the scatter list instead of just
the last one?
> + break;
> + }
> + offset += page_len;
> + }
> +
> + return ret;
> +}
next prev parent reply other threads:[~2014-08-12 1:35 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-11 22:45 [PATCH v5 0/1] Add iommu map_sg/unmap_sg API Olav Haugan
2014-08-11 22:45 ` [PATCH v5 1/1] iommu-api: Add map_sg/unmap_sg functions Olav Haugan
2014-08-12 1:35 ` Konrad Rzeszutek Wilk [this message]
2014-08-12 16:53 ` Olav Haugan
2014-08-12 1:51 ` Hiroshi Doyu
2014-08-12 10:48 ` Rob Clark
2014-08-12 16:56 ` Olav Haugan
2014-08-18 14:07 ` joro at 8bytes.org
2014-08-18 18:32 ` Rob Clark
2014-08-18 20:48 ` Olav Haugan
2014-08-18 21:26 ` joro at 8bytes.org
2014-08-18 21:32 ` Olav Haugan
2014-08-12 16:55 ` Laurent Pinchart
2014-08-12 17:10 ` Olav Haugan
2014-08-18 21:55 ` Joerg Roedel
2014-08-18 22:47 ` Olav Haugan
2014-08-19 11:59 ` Joerg Roedel
2014-08-19 16:11 ` Laurent Pinchart
2014-08-19 18:40 ` Olav Haugan
2014-08-19 20:52 ` Laurent Pinchart
2014-08-20 5:21 ` Thierry Reding
2014-08-20 13:02 ` Konrad Rzeszutek Wilk
2014-08-20 14:15 ` Laurent Pinchart
2014-08-19 18:37 ` Olav Haugan
2014-09-25 17:01 ` Joerg Roedel
2014-10-06 19:02 ` Olav Haugan
2014-10-15 9:16 ` Thierry Reding
2014-10-16 17:23 ` Olav Haugan
2014-10-17 9:09 ` Joerg Roedel
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