On Sat, Oct 31, 2015 at 02:23:31PM -0700, Linus Torvalds wrote:

> The other stuff we probably can't do all that much about. Unless we
> decide to go for some complicated lockless optimistic file descriptor
> allocation scheme with retry-on-failure instead of locks. Which I'm
> sure is possible, but I'm equally sure is painful.

The interesting part is dup2() - we'd have to do something like
        serialize against other dup2
        was_claimed = atomically set and test bit in bitmap
        if was_claimed
                tofree = fdt->fd[fd];
                if (!tofree)
                        fail with EBUSY
        install into ->fd[...]
        end of critical area
in there; __alloc_fd() could be made retry-on-failure, but I don't see
how to cope with dup2 vs. dup2 without an explicit exclusion.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to