mtd: tests: Replace timeval with ktime_t

Changes the 32-bit time type timeval to the 64-bit time type
ktime_t, since 32-bit systems using struct timeval will break in the
year 2038. Correspondingly change do_gettimeofday() to ktime_get()
since ktime_get returns a ktime_t, but do_gettimeofday returns a
struct timeval.Here, ktime_get() is used instead of ktime_get_real()
since ktime_get() uses monotonic clock.

Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/tests/speedtest.c

@@ -22,6 +22,7 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/init.h>
+#include <linux/ktime.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/err.h>
@@ -49,7 +50,7 @@ static int pgsize;
 static int ebcnt;
 static int pgcnt;
 static int goodebcnt;
-static struct timeval start, finish;
+static ktime_t start, finish;
 
 static int multiblock_erase(int ebnum, int blocks)
 {
@@ -168,12 +169,12 @@ static int read_eraseblock_by_2pages(int ebnum)
 
 static inline void start_timing(void)
 {
-	do_gettimeofday(&start);
+	start = ktime_get();
 }
 
 static inline void stop_timing(void)
 {
-	do_gettimeofday(&finish);
+	finish = ktime_get();
 }
 
 static long calc_speed(void)
@@ -181,8 +182,7 @@ static long calc_speed(void)
 	uint64_t k;
 	long ms;
 
-	ms = (finish.tv_sec - start.tv_sec) * 1000 +
-	     (finish.tv_usec - start.tv_usec) / 1000;
+	ms = ktime_ms_delta(finish, start);
 	if (ms == 0)
 		return 0;
 	k = (uint64_t)goodebcnt * (mtd->erasesize / 1024) * 1000;