Re: zero-copy read() interface

[Jörn Engel]

On Thu, 18 August 2005 12:01:52 +0200, Folkert van Heusden wrote:
> 
> What about a zero-copy read-interface?
> An ioctl (or something) which enables the kernel to do dma directly to
> the userspace. Of course this should be limited to the root-user or a
> user with special capabilities (rights) since if a drive screws up, data
> from a different sector (or so) might end up in the proces' memory. Of
> course copying a sector from kernel- to userspace can be done pretty
> fast but i.m.h.o. all possible speedimprovements should be made unless
> unclean.

Just use mmap().  Unlike your proposal, it cooperates with the page
cache.

Jörn

-- 
Don't worry about people stealing your ideas. If your ideas are any good,
you'll have to ram them down people's throats.
-- Howard Aiken quoted by Ken Iverson quoted by Jim Horning quoted by
   Raph Levien, 1979
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