Re: zero-copy read() interface

[Christoph Hellwig <hch@infradead.org>]

On Thu, Aug 18, 2005 at 12:01:52PM +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.

It's called O_DIRECT, and doesn't need root, just some alignment-constraints.

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