[PATCH 1/2] select: change do_poll() to return -ERESTARTNOHAND rather than -EINTR

[Oleg Nesterov]

do_poll() returns -EINTR if interrupted and after that all its callers
have to translate it into -ERESTARTNOHAND. Change do_poll() to return
-ERESTARTNOHAND and update (simplify) the callers.

Note that this also unifies all users of restore_saved_sigmask_unless(),
see the next patch.

Signed-off-by: Oleg Nesterov <o...@redhat.com>
---
 fs/select.c | 30 +++++++-----------------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/fs/select.c b/fs/select.c
index 1fc1b24..57712c3 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -925,7 +925,7 @@ static int do_poll(struct poll_list *list, struct 
poll_wqueues *wait,
                if (!count) {
                        count = wait->error;
                        if (signal_pending(current))
-                               count = -EINTR;
+                               count = -ERESTARTNOHAND;
                }
                if (count || timed_out)
                        break;
@@ -1040,7 +1040,7 @@ static long do_restart_poll(struct restart_block 
*restart_block)
 
        ret = do_sys_poll(ufds, nfds, to);
 
-       if (ret == -EINTR) {
+       if (ret == -ERESTARTNOHAND) {
                restart_block->fn = do_restart_poll;
                ret = -ERESTART_RESTARTBLOCK;
        }
@@ -1061,7 +1061,7 @@ SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, 
unsigned int, nfds,
 
        ret = do_sys_poll(ufds, nfds, to);
 
-       if (ret == -EINTR) {
+       if (ret == -ERESTARTNOHAND) {
                struct restart_block *restart_block;
 
                restart_block = &current->restart_block;
@@ -1102,11 +1102,7 @@ SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, 
unsigned int, nfds,
                return ret;
 
        ret = do_sys_poll(ufds, nfds, to);
-
-       restore_saved_sigmask_unless(ret == -EINTR);
-       /* We can restart this syscall, usually */
-       if (ret == -EINTR)
-               ret = -ERESTARTNOHAND;
+       restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
        ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);
 
        return ret;
@@ -1135,11 +1131,7 @@ SYSCALL_DEFINE5(ppoll_time32, struct pollfd __user *, 
ufds, unsigned int, nfds,
                return ret;
 
        ret = do_sys_poll(ufds, nfds, to);
-
-       restore_saved_sigmask_unless(ret == -EINTR);
-       /* We can restart this syscall, usually */
-       if (ret == -EINTR)
-               ret = -ERESTARTNOHAND;
+       restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
        ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);
 
        return ret;
@@ -1413,11 +1405,7 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time32, struct pollfd 
__user *, ufds,
                return ret;
 
        ret = do_sys_poll(ufds, nfds, to);
-
-       restore_saved_sigmask_unless(ret == -EINTR);
-       /* We can restart this syscall, usually */
-       if (ret == -EINTR)
-               ret = -ERESTARTNOHAND;
+       restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
        ret = poll_select_copy_remaining(&end_time, tsp, PT_OLD_TIMESPEC, ret);
 
        return ret;
@@ -1446,11 +1434,7 @@ COMPAT_SYSCALL_DEFINE5(ppoll_time64, struct pollfd 
__user *, ufds,
                return ret;
 
        ret = do_sys_poll(ufds, nfds, to);
-
-       restore_saved_sigmask_unless(ret == -EINTR);
-       /* We can restart this syscall, usually */
-       if (ret == -EINTR)
-               ret = -ERESTARTNOHAND;
+       restore_saved_sigmask_unless(ret == -ERESTARTNOHAND);
        ret = poll_select_copy_remaining(&end_time, tsp, PT_TIMESPEC, ret);
 
        return ret;
-- 
2.5.0