md: use seconds granularity for error logging

The md code stores the exact time of the last error in the
last_read_error variable using a timespec structure. It only
ever uses the seconds portion of that though, so we can
use a scalar for it.

There won't be an overflow in 2038 here, because it already
used monotonic time and 32-bit is enough for that, but I've
decided to use time64_t for consistency in the conversion.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Shaohua Li <shli@fb.com>

3 files changed, 7 insertions, 9 deletions

diff --git a/drivers/md/md.c b/drivers/md/md.c
index 2ed547f5c3b6..4b8a264e9777 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -3173,8 +3173,7 @@ int md_rdev_init(struct md_rdev *rdev)
         rdev->data_offset = 0;
         rdev->new_data_offset = 0;
         rdev->sb_events = 0;
-        rdev->last_read_error.tv_sec  = 0;
-        rdev->last_read_error.tv_nsec = 0;
+        rdev->last_read_error = 0;
         rdev->sb_loaded = 0;
         rdev->bb_page = NULL;
         atomic_set(&rdev->nr_pending, 0);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index dc65ca65b26e..fd56cfd8c368 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -99,7 +99,7 @@ struct md_rdev {
         atomic_t        read_errors;    /* number of consecutive read errors that
                                          * we have tried to ignore.
                                          */
-        struct timespec last_read_error;        /* monotonic time since our
+        time64_t        last_read_error;        /* monotonic time since our
                                                  * last read error
                                                  */
         atomic_t        corrected_errors; /* number of corrected read errors,
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 8ee5d96e6a2d..f7f3c8a63419 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2174,21 +2174,20 @@ static void recovery_request_write(struct mddev *mddev, struct r10bio *r10_bio)
  */
 static void check_decay_read_errors(struct mddev *mddev, struct md_rdev *rdev)
 {
-        struct timespec cur_time_mon;
+        long cur_time_mon;
         unsigned long hours_since_last;
         unsigned int read_errors = atomic_read(&rdev->read_errors);
 
-        ktime_get_ts(&cur_time_mon);
+        cur_time_mon = ktime_get_seconds();
 
-        if (rdev->last_read_error.tv_sec == 0 &&
-            rdev->last_read_error.tv_nsec == 0) {
+        if (rdev->last_read_error == 0) {
                 /* first time we've seen a read error */
                 rdev->last_read_error = cur_time_mon;
                 return;
         }
 
-        hours_since_last = (cur_time_mon.tv_sec -
-                            rdev->last_read_error.tv_sec) / 3600;
+        hours_since_last = (long)(cur_time_mon -
+                            rdev->last_read_error) / 3600;
 
         rdev->last_read_error = cur_time_mon;