[lkml]   [2017]   [Apr]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC 5/8] scatterlist: Modify SG copy functions to support io memory.
On Mon, Apr 3, 2017 at 2:20 PM, Logan Gunthorpe <> wrote:
> Hi Christoph,
> What are your thoughts on an approach like the following untested
> draft patch.
> The patch (if fleshed out) makes it so iomem can be used in an sgl
> and WARN_ONs will occur in places where drivers attempt to access
> iomem directly through the sgl.
> I'd also probably create a p2pmem_alloc_sgl helper function so driver
> writers wouldn't have to mess with sg_set_iomem_page.
> With all that in place, it should be relatively safe for drivers to
> implement p2pmem even though we'd still technically be violating the
> __iomem boundary in some places.

Just reacting to this mail, I still haven't had a chance to take a
look at the rest of the series.

The pfn_t type was invented to carry extra type and page lookup
information about the memory behind a given pfn. At first glance that
seems a more natural place to carry an indication that this is an
"I/O" pfn.

 \ /
  Last update: 2017-04-03 23:45    [W:0.068 / U:0.728 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site