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Subject[PATCH -mm 0/1] signal: simplify set_user_sigmask/restore_user_sigmask
On top of

signal-remove-the-wrong-signal_pending-check-in-restore_user_sigmask.patch

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;

set_restore_sigmask();
current->saved_sigmask = current->blocked;
set_current_blocked(kmask);

return 0;
}

static inline void restore_saved_sigmask_unless(bool interrupted)
{
if (interrupted)
WARN_ON(!test_thread_flag(TIF_SIGPENDING));
else
restore_saved_sigmask();
}

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;
}

Oleg.

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