linux-kernel - [PATCH 8/9] select/restart_block: Convert poll's timeout to u64

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Date:   Mon,  9 Sep 2019 11:23:39 +0100
From:   Dmitry Safonov <dima@...sta.com>
To:     linux-kernel@...r.kernel.org
Cc:     Dmitry Safonov <0x7f454c46@...il.com>,
        Dmitry Safonov <dima@...sta.com>,
        Adrian Reber <adrian@...as.de>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Andrei Vagin <avagin@...nvz.org>,
        Andy Lutomirski <luto@...nel.org>,
        Cyrill Gorcunov <gorcunov@...nvz.org>,
        Ingo Molnar <mingo@...hat.com>,
        Oleg Nesterov <oleg@...hat.com>,
        Pavel Emelyanov <xemul@...tuozzo.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        containers@...ts.linux-foundation.org,
        linux-fsdevel@...r.kernel.org
Subject: [PATCH 8/9] select/restart_block: Convert poll's timeout to u64

All preparations have been done - now poll() can set u64 timeout in
restart_block. It allows to do the next step - unifying all timeouts in
restart_block and provide ptrace() API to read it.

Signed-off-by: Dmitry Safonov <dima@...sta.com>
---
 fs/select.c                   | 27 +++++++--------------------
 include/linux/restart_block.h |  4 +---
 2 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/fs/select.c b/fs/select.c
index 4af88feaa2fe..ff2b9c4865cd 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -1001,14 +1001,9 @@ static long do_restart_poll(struct restart_block *restart_block)
 {
 	struct pollfd __user *ufds = restart_block->poll.ufds;
 	int nfds = restart_block->poll.nfds;
-	ktime_t timeout = 0;
+	ktime_t timeout = restart_block->poll.timeout;
 	int ret;
 
-	if (restart_block->poll.has_timeout) {
-		timeout = ktime_set(restart_block->poll.tv_sec,
-				    restart_block->poll.tv_nsec);
-	}
-
 	ret = do_sys_poll(ufds, nfds, timeout);
 
 	if (ret == -ERESTARTNOHAND) {
@@ -1021,14 +1016,12 @@ static long do_restart_poll(struct restart_block *restart_block)
 SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
 		int, timeout_msecs)
 {
-	struct timespec64 end_time;
 	ktime_t timeout = 0;
 	int ret;
 
 	if (timeout_msecs >= 0) {
-		poll_select_set_timeout(&end_time, timeout_msecs / MSEC_PER_SEC,
-			NSEC_PER_MSEC * (timeout_msecs % MSEC_PER_SEC));
-		timeout = timespec64_to_ktime(end_time);
+		timeout = ktime_add_ms(0, timeout_msecs);
+		timeout = ktime_add_safe(ktime_get(), timeout);
 	}
 
 	ret = do_sys_poll(ufds, nfds, timeout);
@@ -1037,16 +1030,10 @@ SYSCALL_DEFINE3(poll, struct pollfd __user *, ufds, unsigned int, nfds,
 		struct restart_block *restart_block;
 
 		restart_block = &current->restart_block;
-		restart_block->fn = do_restart_poll;
-		restart_block->poll.ufds = ufds;
-		restart_block->poll.nfds = nfds;
-
-		if (timeout_msecs >= 0) {
-			restart_block->poll.tv_sec = end_time.tv_sec;
-			restart_block->poll.tv_nsec = end_time.tv_nsec;
-			restart_block->poll.has_timeout = 1;
-		} else
-			restart_block->poll.has_timeout = 0;
+		restart_block->fn		= do_restart_poll;
+		restart_block->poll.ufds	= ufds;
+		restart_block->poll.nfds	= nfds;
+		restart_block->poll.timeout	= timeout;
 
 		ret = -ERESTART_RESTARTBLOCK;
 	}
diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h
index e66e982105f4..63d647b65395 100644
--- a/include/linux/restart_block.h
+++ b/include/linux/restart_block.h
@@ -49,11 +49,9 @@ struct restart_block {
 		} nanosleep;
 		/* For poll */
 		struct {
+			u64 timeout;
 			struct pollfd __user *ufds;
 			int nfds;
-			int has_timeout;
-			unsigned long tv_sec;
-			unsigned long tv_nsec;
 		} poll;
 	};
 };
-- 
2.23.0