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 <a...@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

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