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, 21 insertions, 20 deletions

diff --git a/kernel/power/swap.c b/kernel/power/swap.c
index aaa3261dea5d..2c9d6d50a816 100644
--- a/kernel/power/swap.c
+++ b/kernel/power/swap.c
@@ -30,6 +30,7 @@
 #include <linux/atomic.h>
 #include <linux/kthread.h>
 #include <linux/crc32.h>
+#include <linux/ktime.h>
 
 #include "power.h"
 
@@ -445,8 +446,8 @@ static int save_image(struct swap_map_handle *handle,
         int nr_pages;
         int err2;
         struct bio *bio;
-        struct timeval start;
-        struct timeval stop;
+        ktime_t start;
+        ktime_t stop;
 
         printk(KERN_INFO "PM: Saving image data pages (%u pages)...\n",
                 nr_to_write);
@@ -455,7 +456,7 @@ static int save_image(struct swap_map_handle *handle,
                 m = 1;
         nr_pages = 0;
         bio = NULL;
-        do_gettimeofday(&start);
+        start = ktime_get();
         while (1) {
                 ret = snapshot_read_next(snapshot);
                 if (ret <= 0)
@@ -469,12 +470,12 @@ static int save_image(struct swap_map_handle *handle,
                 nr_pages++;
         }
         err2 = hib_wait_on_bio_chain(&bio);
-        do_gettimeofday(&stop);
+        stop = ktime_get();
         if (!ret)
                 ret = err2;
         if (!ret)
                 printk(KERN_INFO "PM: Image saving done.\n");
-        swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
+        swsusp_show_speed(start, stop, nr_to_write, "Wrote");
         return ret;
 }
 
@@ -580,8 +581,8 @@ static int save_image_lzo(struct swap_map_handle *handle,
         int nr_pages;
         int err2;
         struct bio *bio;
-        struct timeval start;
-        struct timeval stop;
+        ktime_t start;
+        ktime_t stop;
         size_t off;
         unsigned thr, run_threads, nr_threads;
         unsigned char *page = NULL;
@@ -674,7 +675,7 @@ static int save_image_lzo(struct swap_map_handle *handle,
                 m = 1;
         nr_pages = 0;
         bio = NULL;
-        do_gettimeofday(&start);
+        start = ktime_get();
         for (;;) {
                 for (thr = 0; thr < nr_threads; thr++) {
                         for (off = 0; off < LZO_UNC_SIZE; off += PAGE_SIZE) {
@@ -759,12 +760,12 @@ static int save_image_lzo(struct swap_map_handle *handle,
 
 out_finish:
         err2 = hib_wait_on_bio_chain(&bio);
-        do_gettimeofday(&stop);
+        stop = ktime_get();
         if (!ret)
                 ret = err2;
         if (!ret)
                 printk(KERN_INFO "PM: Image saving done.\n");
-        swsusp_show_speed(&start, &stop, nr_to_write, "Wrote");
+        swsusp_show_speed(start, stop, nr_to_write, "Wrote");
 out_clean:
         if (crc) {
                 if (crc->thr)
@@ -965,8 +966,8 @@ static int load_image(struct swap_map_handle *handle,
 {
         unsigned int m;
         int ret = 0;
-        struct timeval start;
-        struct timeval stop;
+        ktime_t start;
+        ktime_t stop;
         struct bio *bio;
         int err2;
         unsigned nr_pages;
@@ -978,7 +979,7 @@ static int load_image(struct swap_map_handle *handle,
                 m = 1;
         nr_pages = 0;
         bio = NULL;
-        do_gettimeofday(&start);
+        start = ktime_get();
         for ( ; ; ) {
                 ret = snapshot_write_next(snapshot);
                 if (ret <= 0)
@@ -996,7 +997,7 @@ static int load_image(struct swap_map_handle *handle,
                 nr_pages++;
         }
         err2 = hib_wait_on_bio_chain(&bio);
-        do_gettimeofday(&stop);
+        stop = ktime_get();
         if (!ret)
                 ret = err2;
         if (!ret) {
@@ -1005,7 +1006,7 @@ static int load_image(struct swap_map_handle *handle,
                 if (!snapshot_image_loaded(snapshot))
                         ret = -ENODATA;
         }
-        swsusp_show_speed(&start, &stop, nr_to_read, "Read");
+        swsusp_show_speed(start, stop, nr_to_read, "Read");
         return ret;
 }
 
@@ -1067,8 +1068,8 @@ static int load_image_lzo(struct swap_map_handle *handle,
         int ret = 0;
         int eof = 0;
         struct bio *bio;
-        struct timeval start;
-        struct timeval stop;
+        ktime_t start;
+        ktime_t stop;
         unsigned nr_pages;
         size_t off;
         unsigned i, thr, run_threads, nr_threads;
@@ -1190,7 +1191,7 @@ static int load_image_lzo(struct swap_map_handle *handle,
                 m = 1;
         nr_pages = 0;
         bio = NULL;
-        do_gettimeofday(&start);
+        start = ktime_get();
 
         ret = snapshot_write_next(snapshot);
         if (ret <= 0)
@@ -1343,7 +1344,7 @@ out_finish:
                 wait_event(crc->done, atomic_read(&crc->stop));
                 atomic_set(&crc->stop, 0);
         }
-        do_gettimeofday(&stop);
+        stop = ktime_get();
         if (!ret) {
                 printk(KERN_INFO "PM: Image loading done.\n");
                 snapshot_write_finalize(snapshot);
@@ -1359,7 +1360,7 @@ out_finish:
                         }
                 }
         }
-        swsusp_show_speed(&start, &stop, nr_to_read, "Read");
+        swsusp_show_speed(start, stop, nr_to_read, "Read");
 out_clean:
         for (i = 0; i < ring_size; i++)
                 free_page((unsigned long)page[i]);