linux-kernel - [PATCH 4/8] ipmi: kill off 'timespec' usage again

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Date:   Fri,  8 Nov 2019 21:34:27 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     y2038@...ts.linaro.org, Corey Minyard <minyard@....org>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, Corey Minyard <cminyard@...sta.com>,
        openipmi-developer@...ts.sourceforge.net
Subject: [PATCH 4/8] ipmi: kill off 'timespec' usage again

'struct timespec' is getting removed from the kernel. The usage in ipmi
was fixed before in commit 48862ea2ce86 ("ipmi: Update timespec usage
to timespec64"), but unfortunately it crept back in.

The busy looping code can better use ktime_t anyway, so use that
there to simplify the implementation.

Fixes: cbb19cb1eef0 ("ipmi_si: Convert timespec64 to timespec")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/char/ipmi/ipmi_si_intf.c | 40 +++++++++++---------------------
 1 file changed, 13 insertions(+), 27 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index 6b9a0593d2eb..c7cc8538b84a 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -265,10 +265,10 @@ static void cleanup_ipmi_si(void);
 #ifdef DEBUG_TIMING
 void debug_timestamp(char *msg)
 {
-	struct timespec t;
+	struct timespec64 t;
 
-	ktime_get_ts(&t);
-	pr_debug("**%s: %ld.%9.9ld\n", msg, (long) t.tv_sec, t.tv_nsec);
+	ktime_get_ts64(&t);
+	pr_debug("**%s: %lld.%9.9ld\n", msg, t.tv_sec, t.tv_nsec);
 }
 #else
 #define debug_timestamp(x)
@@ -935,38 +935,25 @@ static void set_run_to_completion(void *send_info, bool i_run_to_completion)
 }
 
 /*
- * Use -1 in the nsec value of the busy waiting timespec to tell that
- * we are spinning in kipmid looking for something and not delaying
- * between checks
+ * Use -1 as a special constant to tell that we are spinning in kipmid
+ * looking for something and not delaying between checks
  */
-static inline void ipmi_si_set_not_busy(struct timespec *ts)
-{
-	ts->tv_nsec = -1;
-}
-static inline int ipmi_si_is_busy(struct timespec *ts)
-{
-	return ts->tv_nsec != -1;
-}
-
+#define IPMI_TIME_NOT_BUSY ns_to_ktime(-1ull)
 static inline bool ipmi_thread_busy_wait(enum si_sm_result smi_result,
 					 const struct smi_info *smi_info,
-					 struct timespec *busy_until)
+					 ktime_t *busy_until)
 {
 	unsigned int max_busy_us = 0;
 
 	if (smi_info->si_num < num_max_busy_us)
 		max_busy_us = kipmid_max_busy_us[smi_info->si_num];
 	if (max_busy_us == 0 || smi_result != SI_SM_CALL_WITH_DELAY)
-		ipmi_si_set_not_busy(busy_until);
-	else if (!ipmi_si_is_busy(busy_until)) {
-		ktime_get_ts(busy_until);
-		timespec_add_ns(busy_until, max_busy_us * NSEC_PER_USEC);
+		*busy_until = IPMI_TIME_NOT_BUSY;
+	else if (*busy_until == IPMI_TIME_NOT_BUSY) {
+		*busy_until = ktime_get() + max_busy_us * NSEC_PER_USEC;
 	} else {
-		struct timespec now;
-
-		ktime_get_ts(&now);
-		if (unlikely(timespec_compare(&now, busy_until) > 0)) {
-			ipmi_si_set_not_busy(busy_until);
+		if (unlikely(ktime_get() > *busy_until)) {
+			*busy_until = IPMI_TIME_NOT_BUSY;
 			return false;
 		}
 	}
@@ -988,9 +975,8 @@ static int ipmi_thread(void *data)
 	struct smi_info *smi_info = data;
 	unsigned long flags;
 	enum si_sm_result smi_result;
-	struct timespec busy_until = { 0, 0 };
+	ktime_t busy_until = IPMI_TIME_NOT_BUSY;
 
-	ipmi_si_set_not_busy(&busy_until);
 	set_user_nice(current, MAX_NICE);
 	while (!kthread_should_stop()) {
 		int busy_wait;
-- 
2.20.0