PM / Hibernate: Migrate to ktime_t

This patch migrates swsusp_show_speed and its callers to using ktime_t instead
of 'struct timeval' which suffers from the y2038 problem.

Changes to swsusp_show_speed:
        - use ktime_t for start and stop times
        - pass start and stop times by value
Calling functions affected:
        - load_image
        - load_image_lzo
        - save_image
        - save_image_lzo
        - hibernate_preallocate_memory
Design decisions:
        - use ktime_t to preserve same granularity of reporting as before
        - use centisecs logic as before to avoid 'div by zero' issues caused by
          using seconds and nanoseconds directly
        - use monotonic time (ktime_get()) since we only care about elapsed time.

Signed-off-by: Tina Ruchandani <ruchandani.tina@gmail.com>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 5 insertions, 4 deletions

diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 791a61892bb5..0c40c16174b4 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -28,6 +28,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/compiler.h>
+#include <linux/ktime.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -1576,11 +1577,11 @@ int hibernate_preallocate_memory(void)
         struct zone *zone;
         unsigned long saveable, size, max_size, count, highmem, pages = 0;
         unsigned long alloc, save_highmem, pages_highmem, avail_normal;
-        struct timeval start, stop;
+        ktime_t start, stop;
         int error;
 
         printk(KERN_INFO "PM: Preallocating image memory... ");
-        do_gettimeofday(&start);
+        start = ktime_get();
 
         error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
         if (error)
@@ -1709,9 +1710,9 @@ int hibernate_preallocate_memory(void)
         free_unnecessary_pages();
 
  out:
-        do_gettimeofday(&stop);
+        stop = ktime_get();
         printk(KERN_CONT "done (allocated %lu pages)\n", pages);
-        swsusp_show_speed(&start, &stop, pages, "Allocated");
+        swsusp_show_speed(start, stop, pages, "Allocated");
 
         return 0;