signal: simplify set_user_sigmask/restore_user_sigmask

task->saved_sigmask and ->restore_sigmask are only used in the ret-from-
syscall paths.  This means that set_user_sigmask() can save ->blocked in
->saved_sigmask and do set_restore_sigmask() to indicate that ->blocked
was modified.

This way the callers do not need 2 sigset_t's passed to set/restore and
restore_user_sigmask() renamed to restore_saved_sigmask_unless() turns
into the trivial helper which just calls restore_saved_sigmask().

Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Oleg Nesterov <[email protected]>
Cc: Deepa Dinamani <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Eric Wong <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: David Laight <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
8 files changed