On 13/10/2020 22.54, Christian Brauner wrote:
> On Tue, Oct 13, 2020 at 04:06:08PM +0200, Giuseppe Scrivano wrote:
>
> Hey Guiseppe,
>
> Thanks for the patch!
>
>> When the flag CLOSE_RANGE_CLOEXEC is set, close_range doesn't
>> immediately close the files but it sets the close-on-exec bit.
>
> Hm, please expand on the use-cases a little here so people know where
> and how this is useful. Keeping the rationale for a change in the commit
> log is really important.
>
> I think I don't have quarrels with this patch in principle but I wonder
> if something like the following wouldn't be easier to follow:
>
> diff --git a/fs/file.c b/fs/file.c
> index 21c0893f2f1d..872a4098c3be 100644
> --- a/fs/file.c
> +++ b/fs/file.c
> @@ -672,6 +672,32 @@ int __close_fd(struct files_struct *files, unsigned fd)
> }
> EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
>
> +static inline void __range_cloexec(struct files_struct *cur_fds,
> + unsigned int fd, unsigned max_fd)
> +{
> + struct fdtable *fdt;
> + spin_lock(&cur_fds->file_lock);
> + fdt = files_fdtable(cur_fds);
> + while (fd <= max_fd)
> + __set_close_on_exec(fd++, fdt);
Doesn't that want to be
bitmap_set(fdt->close_on_exec, fd, max_fd - fd + 1)
to do word-at-a-time? I assume this would mostly be called with (3, ~0U)
as arguments or something like that.
Rasmus
