Re: [PATCH 1/2] open: add close_range()
From: Al Viro
Date: Tue May 21 2019 - 15:22:58 EST
On Tue, May 21, 2019 at 05:30:27PM +0100, David Howells wrote:
> If we can live with close_from(int first) rather than close_range(), then this
> can perhaps be done a lot more efficiently by:
>
> new = alloc_fdtable(first);
> spin_lock(&files->file_lock);
> old = files_fdtable(files);
> copy_fds(new, old, 0, first - 1);
> rcu_assign_pointer(files->fdt, new);
> spin_unlock(&files->file_lock);
> clear_fds(old, 0, first - 1);
> close_fdt_from(old, first);
> kfree_rcu(old);
I really hate to think how that would interact with POSIX locks...