drbd: Fixes to the new delay_probes code

* Only send delay_probes with protocol 93 or newer
* drbd_send_delay_probes() is called only from worker context,
  no atomic_t needed for delay_seq

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

3 files changed, 8 insertions, 9 deletions

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 37380d2c869d..45d9a4534c40 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -552,7 +552,7 @@ struct p_delay_probe {
 
 struct delay_probe {
         struct list_head list;
-        int seq_num;
+        unsigned int seq_num;
         struct timeval time;
 };
 
@@ -1048,9 +1048,9 @@ struct drbd_conf {
         char congestion_reason;  /* Why we where congested... */
         struct list_head delay_probes; /* protected by peer_seq_lock */
         int data_delay;   /* Delay of packets on the data-sock behind meta-sock */
-        atomic_t delay_seq; /* To generate sequence numbers of delay probes */
+        unsigned int delay_seq; /* To generate sequence numbers of delay probes */
         struct timeval dps_time; /* delay-probes-start-time */
-        int dp_volume_last;  /* send_cnt of last delay probe */
+        unsigned int dp_volume_last;  /* send_cnt of last delay probe */
         int c_sync_rate; /* current resync rate after delay_probe magic */
 };
 
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 44cc7b415ed4..3aa0add1c230 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2199,7 +2199,7 @@ static int drbd_send_delay_probe(struct drbd_conf *mdev, struct drbd_socket *ds)
                 do_gettimeofday(&now);
                 offset = now.tv_usec - mdev->dps_time.tv_usec +
                          (now.tv_sec - mdev->dps_time.tv_sec) * 1000000;
-                dp.seq_num  = cpu_to_be32(atomic_read(&mdev->delay_seq));
+                dp.seq_num  = cpu_to_be32(mdev->delay_seq);
                 dp.offset   = cpu_to_be32(offset);
 
                 ok = _drbd_send_cmd(mdev, ds->socket, P_DELAY_PROBE,
@@ -2213,7 +2213,8 @@ static int drbd_send_delay_probe(struct drbd_conf *mdev, struct drbd_socket *ds)
 static int drbd_send_delay_probes(struct drbd_conf *mdev)
 {
         int ok;
-        atomic_inc(&mdev->delay_seq);
+
+        mdev->delay_seq++;
         do_gettimeofday(&mdev->dps_time);
         ok = drbd_send_delay_probe(mdev, &mdev->meta);
         ok = ok && drbd_send_delay_probe(mdev, &mdev->data);
@@ -2355,7 +2356,7 @@ static int _drbd_send_zc_bio(struct drbd_conf *mdev, struct bio *bio)
 
 static void consider_delay_probes(struct drbd_conf *mdev)
 {
-        if (mdev->state.conn != C_SYNC_SOURCE)
+        if (mdev->state.conn != C_SYNC_SOURCE || mdev->agreed_pro_version < 93)
                 return;
 
         if (mdev->dp_volume_last + mdev->sync_conf.dp_volume * 2 < mdev->send_cnt)
@@ -2677,7 +2678,6 @@ void drbd_init_set_defaults(struct drbd_conf *mdev)
         atomic_set(&mdev->net_cnt, 0);
         atomic_set(&mdev->packet_seq, 0);
         atomic_set(&mdev->pp_in_use, 0);
-        atomic_set(&mdev->delay_seq, 0);
 
         mutex_init(&mdev->md_io_mutex);
         mutex_init(&mdev->data.mutex);
diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index 81dea0a85933..d0f1767ea4c3 100644
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -86,8 +86,7 @@ static void drbd_syncer_progress(struct drbd_conf *mdev, struct seq_file *seq)
                            mdev->data_delay / 1000,
                            (mdev->data_delay % 1000) / 100);
         else if (mdev->state.conn == C_SYNC_SOURCE)
-                seq_printf(seq, " delay_probe: %d\n\t",
-                           atomic_read(&mdev->delay_seq));
+                seq_printf(seq, " delay_probe: %u\n\t", mdev->delay_seq);
 
         /* see drivers/md/md.c
          * We do not want to overflow, so the order of operands and