Re: TAKE - fix O_DIRECT and uninitialized user memory

[Andrew Morton <akpm@xxxxxxxxx>]

Andrew Morton <akpm@xxxxxxxxx> wrote:
>
> oops.
> 
>  What happens if an application passes multiple presentations of
>  the same page into a single non-O_DIRECT write() or read()?
> 
>  ie:
> 
>       mmap(buf, 4096, PROT_READ, MAP_FIXED, fd1, 0);
>       mmap(buf+4096, 4096, PROT_READ, MAP_FIXED, fd1, 0);
>       write(fd2, buf, 8192);

oops.  Forget I said that.  I'll go back to sleep now.