On Thu, Jun 18, 2020 at 04:46:27PM +0200, Christoph Hellwig wrote:
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -1626,6 +1626,22 @@ long kernel_wait4(pid_t upid, int __user *stat_addr, int options,
> return ret;
> }
>
> +int kernel_wait(pid_t pid, int *stat)
> +{
> + struct wait_opts wo = {
> + .wo_type = PIDTYPE_PID,
> + .wo_pid = find_get_pid(pid),
> + .wo_flags = WEXITED,
> + };
> + int ret;
> +
> + ret = do_wait(&wo);
> + if (ret > 0 && wo.wo_stat)
> + *stat = wo.wo_stat;
Since all we care about is WEXITED, that could be simplified
to something like this:
if (ret > 0 && KWIFEXITED(wo.wo_stat)
*stat = KWEXITSTATUS(wo.wo_stat)
Otherwise callers have to use W*() wrappers.
> + put_pid(wo.wo_pid);
> + return ret;
> +}
Then we don't get *any* in-kernel code dealing with the W*() crap.
I just unwrapped this for the umh [0], given that otherwise we'd
have to use KW*() callers elsewhere. Doing it upshot one level
further would be even better.
[0] https://lkml.kernel.org/r/20200610154923.27510-1-mcgrof@xxxxxxxxxx
Luis
