[PATCH] epoll_pwait()

Implement the epoll_pwait system call, that extend the event wait mechanism
with the same logic ppoll and pselect do.  The definition of epoll_pwait
is:

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

The difference between the vanilla epoll_wait and epoll_pwait is that the
latter allows the caller to specify a signal mask to be set while waiting
for events.  Hence epoll_pwait will wait until either one monitored event,
or an unmasked signal happen.  If sigmask is NULL, the epoll_pwait system
call will act exactly like epoll_wait.  For the POSIX definition of
pselect, information is available here:

http://www.opengroup.org/onlinepubs/009695399/functions/select.html

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 6 insertions, 1 deletions

diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index 3ca7ab963d7d..beeeaf6b054a 100644
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -324,10 +324,11 @@
 #define __NR_vmsplice           316
 #define __NR_move_pages         317
 #define __NR_getcpu             318
+#define __NR_epoll_pwait        319
 
 #ifdef __KERNEL__
 
-#define NR_syscalls 319
+#define NR_syscalls 320
 #include <linux/err.h>
 
 /*
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index b0ace3fd7eb9..1912c6cbef55 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -431,6 +431,10 @@ asmlinkage long sys_epoll_ctl(int epfd, int op, int fd,
                                 struct epoll_event __user *event);
 asmlinkage long sys_epoll_wait(int epfd, struct epoll_event __user *events,
                                 int maxevents, int timeout);
+asmlinkage long sys_epoll_pwait(int epfd, struct epoll_event __user *events,
+                                int maxevents, int timeout,
+                                const sigset_t __user *sigmask,
+                                size_t sigsetsize);
 asmlinkage long sys_gethostname(char __user *name, int len);
 asmlinkage long sys_sethostname(char __user *name, int len);
 asmlinkage long sys_setdomainname(char __user *name, int len);