[PATCH] staging: gasket remove current_kernel_time usage

[Arnd Bergmann <arnd@arndb.de>]

A new user of the deprecated current_kernel_time() function has appeared
here. This code won't work correct during leap seconds or a concurrent
settimeofday() call, and it probably doesn't do what the author intended
even for the normal case, as it passes a timeout in nanoseconds but
reads the time using a jiffies-granularity accessor.

I'm changing it to ktime_get_ns() here, which simplifies the logic,
and uses a high-res clocksource. This is a bit slower, but that
probably doesn't matter in a busy-wait loop.

Note: it also doesn't matter in the current version, as there are no
callers of this function.

Fixes: 9a69f5087ccc ("drivers/staging: Gasket driver framework + Apex driver")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/staging/gasket/gasket_core.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/staging/gasket/gasket_core.c b/drivers/staging/gasket/gasket_core.c
index 45914ebc8f44..248c99a841a9 100644
--- a/drivers/staging/gasket/gasket_core.c
+++ b/drivers/staging/gasket/gasket_core.c
@@ -2090,19 +2090,14 @@ int gasket_wait_sync(
 	u64 timeout_ns)
 {
 	u64 reg;
-	struct timespec start_time, cur_time;
-	u64 diff_nanosec;
+	u64 start_time, diff_nanosec;
 	int count = 0;
 
 	reg = gasket_dev_read_64(gasket_dev, bar, offset);
-	start_time = current_kernel_time();
+	start_time = ktime_get_ns();
 	while ((reg & mask) != val) {
 		count++;
-		cur_time = current_kernel_time();
-		diff_nanosec = (u64)(cur_time.tv_sec - start_time.tv_sec) *
-				       1000000000LL +
-			       (u64)(cur_time.tv_nsec) -
-			       (u64)(start_time.tv_nsec);
+		diff_nanosec = ktime_get_ns() - start_time;
 		if (diff_nanosec > timeout_ns) {
 			gasket_log_error(
 				gasket_dev,
-- 
2.9.0