The plan is to store what's left of timeout in restart block as ktime_t
which will be used for futex() and nanosleep() timeouts too. That will
be a value to return with a new ptrace() request API.

Convert end_time argument of do_{sys_,}poll() functions to ktime_t as
a preparation ground for storing ktime_t inside restart_block.

Signed-off-by: Dmitry Safonov <d...@arista.com>
---
 fs/select.c | 47 +++++++++++++++++++++++------------------------
 1 file changed, 23 insertions(+), 24 deletions(-)

diff --git a/fs/select.c b/fs/select.c
index 262300e58370..4af88feaa2fe 100644
--- a/fs/select.c
+++ b/fs/select.c
@@ -854,25 +854,22 @@ static inline __poll_t do_pollfd(struct pollfd *pollfd, 
poll_table *pwait,
 }
 
 static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
-                  struct timespec64 *end_time)
+                  ktime_t end_time)
 {
        poll_table* pt = &wait->pt;
-       ktime_t expire, *to = NULL;
+       ktime_t *to = NULL;
        int timed_out = 0, count = 0;
        u64 slack = 0;
        __poll_t busy_flag = net_busy_loop_on() ? POLL_BUSY_LOOP : 0;
        unsigned long busy_start = 0;
 
        /* Optimise the no-wait case */
-       if (end_time && !end_time->tv_sec && !end_time->tv_nsec) {
+       if (ktime_compare(ktime_get(), end_time) >= 0) {
                pt->_qproc = NULL;
                timed_out = 1;
-       }
-
-       if (end_time && !timed_out) {
-               expire = timespec64_to_ktime(*end_time);
-               to = &expire;
-               slack = select_estimate_accuracy(expire);
+       } else {
+               to = &end_time;
+               slack = select_estimate_accuracy(end_time);
        }
 
        for (;;) {
@@ -936,7 +933,7 @@ static int do_poll(struct poll_list *list, struct 
poll_wqueues *wait,
                        sizeof(struct pollfd))
 
 static int do_sys_poll(struct pollfd __user *ufds, unsigned int nfds,
-               struct timespec64 *end_time)
+                      ktime_t end_time)
 {
        struct poll_wqueues table;
        int err = -EFAULT, fdcount, len;
@@ -1004,16 +1001,15 @@ static long do_restart_poll(struct restart_block 
*restart_block)
 {
        struct pollfd __user *ufds = restart_block->poll.ufds;
        int nfds = restart_block->poll.nfds;
-       struct timespec64 *to = NULL, end_time;
+       ktime_t timeout = 0;
        int ret;
 
        if (restart_block->poll.has_timeout) {
-               end_time.tv_sec = restart_block->poll.tv_sec;
-               end_time.tv_nsec = restart_block->poll.tv_nsec;
-               to = &end_time;
+               timeout = ktime_set(restart_block->poll.tv_sec,
+                                   restart_block->poll.tv_nsec);
        }
 
-       ret = do_sys_poll(ufds, nfds, to);
+       ret = do_sys_poll(ufds, nfds, timeout);
 
        if (ret == -ERESTARTNOHAND) {
                restart_block->fn = do_restart_poll;
@@ -1025,16 +1021,17 @@ 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, *to = NULL;
+       struct timespec64 end_time;
+       ktime_t timeout = 0;
        int ret;
 
        if (timeout_msecs >= 0) {
-               to = &end_time;
-               poll_select_set_timeout(to, timeout_msecs / MSEC_PER_SEC,
+               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);
        }
 
-       ret = do_sys_poll(ufds, nfds, to);
+       ret = do_sys_poll(ufds, nfds, timeout);
 
        if (ret == -ERESTARTNOHAND) {
                struct restart_block *restart_block;
@@ -1060,7 +1057,8 @@ static int do_sys_ppoll(struct pollfd __user *ufds, 
unsigned int nfds,
                        void __user *tsp, const void __user *sigmask,
                        size_t sigsetsize, enum poll_time_type pt_type)
 {
-       struct timespec64 ts, end_time, *to = NULL;
+       struct timespec64 ts, *to = NULL;
+       ktime_t timeout = 0;
        int ret;
 
        if (tsp) {
@@ -1078,9 +1076,10 @@ static int do_sys_ppoll(struct pollfd __user *ufds, 
unsigned int nfds,
                        return -ENOSYS;
                }
 
-               to = &end_time;
-               if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
+               to = &ts;
+               if (poll_select_set_timeout(&ts, ts.tv_sec, ts.tv_nsec))
                        return -EINVAL;
+               timeout = timespec64_to_ktime(ts);
        }
 
        if (!in_compat_syscall())
@@ -1091,8 +1090,8 @@ static int do_sys_ppoll(struct pollfd __user *ufds, 
unsigned int nfds,
        if (ret)
                return ret;
 
-       ret = do_sys_poll(ufds, nfds, to);
-       return poll_select_finish(&end_time, tsp, pt_type, ret);
+       ret = do_sys_poll(ufds, nfds, timeout);
+       return poll_select_finish(to, tsp, pt_type, ret);
 }
 
 SYSCALL_DEFINE5(ppoll, struct pollfd __user *, ufds, unsigned int, nfds,
-- 
2.23.0

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