* Chris Wright ([email protected]) wrote:
> From: Vladimir V. Saveliev <[email protected]>
>
> generic_file_buffered_write() prefaults in user pages in order to avoid
> deadlock on copying from the same page as write goes to.
>
> However, it looks like there is a problem when write is vectored:
> fault_in_pages_readable brings in current segment or its part (maxlen).
> OTOH, filemap_copy_from_user_iovec is called to copy number of bytes
> (bytes) which may exceed current segment, so filemap_copy_from_user_iovec
> switches to the next segment which is not brought in yet. Pagefault is
> generated. That causes the deadlock if pagefault is for the same page
> write goes to: page being written is locked and not uptodate, pagefault
> will deadlock trying to lock locked page.
This is dropped for now, as it causes another problem with 0 length
iovecs. Andrew has written a fix and once it's baked in Linus' tree for
a bit we can take back this one plus the fix.
thanks,
-chris
-
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]
