On Sun, 2005-04-24 at 14:24 -0700, Andrew Morton wrote:
> Anton Altaparmakov <[email protected]> wrote:
> >
> > mm/filemap.c::file_buffered_write():
> >
> > - It calls fault_in_pages_readable() which is completely bogus if
> > @nr_segs > 1. It needs to be replaced by a to be written
> > "fault_in_pages_readable_iovec()".
> >
> > - It increments @buf even in the iovec case thus @buf can point to
> > random memory really quickly (in the iovec case) and then it calls
> > fault_in_pages_readable() on this random memory. Ouch...
>
> hmm, yes. Like this?
Yes, certainly a big improvement over what is there at the moment.
> diff -puN mm/filemap.c~generic_file_buffered_write-fixes mm/filemap.c
> --- 25/mm/filemap.c~generic_file_buffered_write-fixes 2005-04-24 14:18:58.445943000 -0700
> +++ 25-akpm/mm/filemap.c 2005-04-24 14:20:21.995241576 -0700
> @@ -1944,7 +1944,7 @@ generic_file_buffered_write(struct kiocb
> buf = iov->iov_base + written;
> else {
> filemap_set_next_iovec(&cur_iov, &iov_base, written);
> - buf = iov->iov_base + iov_base;
> + buf = cur_iov->iov_base + iov_base;
> }
>
> do {
> @@ -2002,9 +2002,11 @@ generic_file_buffered_write(struct kiocb
> count -= status;
> pos += status;
> buf += status;
> - if (unlikely(nr_segs > 1))
> + if (unlikely(nr_segs > 1)) {
> filemap_set_next_iovec(&cur_iov,
> &iov_base, status);
> + buf = cur_iov->iov_base + iov_base;
> + }
> }
> }
> if (unlikely(copied != bytes))
Best regards,
Anton
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
