[PATCH -mm 0/1] signal: simplify set_user_sigmask/restore_user_sigmask

From: Oleg Nesterov
Date: Wed Jun 05 2019 - 12:02:29 EST

On top of


Let me repeat, every file touched by this patch needs more cleanups,
fs/aio.c looks wrong with or without the recent changes. Lets discuss
this later.

To simplify the review, please see the code with this patch applied.
I am using epoll_pwait() as an example because it looks very simple.

Note that this patch moves WARN_ON(!TIF_SIGPENDING) from set_restore_sigmask()
to restore_unless().

int set_user_sigmask(const sigset_t __user *umask, size_t sigsetsize)
sigset_t *kmask;

if (!umask)
return 0;
if (sigsetsize != sizeof(sigset_t))
return -EINVAL;
if (copy_from_user(kmask, umask, sizeof(sigset_t)))
return -EFAULT;

current->saved_sigmask = current->blocked;

return 0;

static inline void restore_saved_sigmask_unless(bool interrupted)
if (interrupted)

SYSCALL_DEFINE6(epoll_pwait, int, epfd, struct epoll_event __user *, events,
int, maxevents, int, timeout, const sigset_t __user *, sigmask,
size_t, sigsetsize)
int error;

* If the caller wants a certain signal mask to be set during the wait,
* we apply it here.
error = set_user_sigmask(sigmask, sigsetsize);
if (error)
return error;

error = do_epoll_wait(epfd, events, maxevents, timeout);
restore_saved_sigmask_unless(error == -EINTR);

return error;