On Tue, Aug 18, 2020 at 06:44:47PM +0100, Matthew Wilcox wrote:
On Tue, Aug 18, 2020 at 07:34:00PM +0200, Christian Brauner wrote:
The only remaining function callable outside of kernel/fork.c is
_do_fork(). It doesn't really follow the naming of kernel-internal
syscall helpers as Christoph righly pointed out. Switch all callers and
references to kernel_clone() and remove _do_fork() once and for all.
My only concern is around return type. long, int, pid_t ... can we
choose one and stick to it? pid_t is probably the right return type
within the kernel, despite the return type of clone3(). It'll save us
some work if we ever go through the hassle of growing pid_t beyond 31-bit.
It should be safe to switch kernel_clone() to return pid_t. (Afair, the
syscall wrappers all have "long" as return type. (I think Linus provided
some more details on that in another mail. Also see
include/linux/syscalls.h. So the return type for clone3() is really
somewhat a userspace thing, I think.)
I wonder whether I should take the opportunity and switch the advertised
flag arguments for the legacy clone() syscalls and kernel_thread() from
unsigned long to unsigned int so we can get rid of the lower
.flags = (lower_32_bits(clone_flags) & ~CSIGNAL),
calls I added to fix sign extension issues glibc ran into...
Christian
