drbd: revert "delay probes", feature is being re-implemented differently

It was a now abandoned attempt to throttle resync bandwidth
based on the delay it causes on the bulk data socket.
It has no userbase yet, and has been disabled by
9173465ccb51c09cc3102a10af93e9f469a0af6f already.
This removes the now unused code.

The basic feature, namely using up "idle" bandwith
of network and disk IO subsystem, with minimal impact
to application IO, is being reimplemented differently.

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

1 files changed, 18 insertions, 95 deletions

diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index cba1deb7b271..20abef531c99 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3555,14 +3555,15 @@ static int receive_bitmap(struct drbd_conf *mdev, struct p_header *h)
         return ok;
 }
 
-static int receive_skip(struct drbd_conf *mdev, struct p_header *h)
+static int receive_skip_(struct drbd_conf *mdev, struct p_header *h, int silent)
 {
         /* TODO zero copy sink :) */
         static char sink[128];
         int size, want, r;
 
-        dev_warn(DEV, "skipping unknown optional packet type %d, l: %d!\n",
-             h->command, h->length);
+        if (!silent)
+                dev_warn(DEV, "skipping unknown optional packet type %d, l: %d!\n",
+                     h->command, h->length);
 
         size = h->length;
         while (size > 0) {
@@ -3574,101 +3575,25 @@ static int receive_skip(struct drbd_conf *mdev, struct p_header *h)
         return size == 0;
 }
 
-static int receive_UnplugRemote(struct drbd_conf *mdev, struct p_header *h)
-{
-        if (mdev->state.disk >= D_INCONSISTENT)
-                drbd_kick_lo(mdev);
-
-        /* Make sure we've acked all the TCP data associated
-         * with the data requests being unplugged */
-        drbd_tcp_quickack(mdev->data.socket);
-
-        return TRUE;
-}
-
-static void timeval_sub_us(struct timeval* tv, unsigned int us)
+static int receive_skip(struct drbd_conf *mdev, struct p_header *h)
 {
-        tv->tv_sec -= us / 1000000;
-        us = us % 1000000;
-        if (tv->tv_usec > us) {
-                tv->tv_usec += 1000000;
-                tv->tv_sec--;
-        }
-        tv->tv_usec -= us;
+        return receive_skip_(mdev, h, 0);
 }
 
-static void got_delay_probe(struct drbd_conf *mdev, int from, struct p_delay_probe *p)
+static int receive_skip_silent(struct drbd_conf *mdev, struct p_header *h)
 {
-        struct delay_probe *dp;
-        struct list_head *le;
-        struct timeval now;
-        int seq_num;
-        int offset;
-        int data_delay;
-
-        seq_num = be32_to_cpu(p->seq_num);
-        offset  = be32_to_cpu(p->offset);
-
-        spin_lock(&mdev->peer_seq_lock);
-        if (!list_empty(&mdev->delay_probes)) {
-                if (from == USE_DATA_SOCKET)
-                        le = mdev->delay_probes.next;
-                else
-                        le = mdev->delay_probes.prev;
-
-                dp = list_entry(le, struct delay_probe, list);
-
-                if (dp->seq_num == seq_num) {
-                        list_del(le);
-                        spin_unlock(&mdev->peer_seq_lock);
-                        do_gettimeofday(&now);
-                        timeval_sub_us(&now, offset);
-                        data_delay =
-                                now.tv_usec - dp->time.tv_usec +
-                                (now.tv_sec - dp->time.tv_sec) * 1000000;
-
-                        if (data_delay > 0)
-                                mdev->data_delay = data_delay;
-
-                        kfree(dp);
-                        return;
-                }
-
-                if (dp->seq_num > seq_num) {
-                        spin_unlock(&mdev->peer_seq_lock);
-                        dev_warn(DEV, "Previous allocation failure of struct delay_probe?\n");
-                        return; /* Do not alloca a struct delay_probe.... */
-                }
-        }
-        spin_unlock(&mdev->peer_seq_lock);
-
-        dp = kmalloc(sizeof(struct delay_probe), GFP_NOIO);
-        if (!dp) {
-                dev_warn(DEV, "Failed to allocate a struct delay_probe, do not worry.\n");
-                return;
-        }
-
-        dp->seq_num = seq_num;
-        do_gettimeofday(&dp->time);
-        timeval_sub_us(&dp->time, offset);
-
-        spin_lock(&mdev->peer_seq_lock);
-        if (from == USE_DATA_SOCKET)
-                list_add(&dp->list, &mdev->delay_probes);
-        else
-                list_add_tail(&dp->list, &mdev->delay_probes);
-        spin_unlock(&mdev->peer_seq_lock);
+        return receive_skip_(mdev, h, 1);
 }
 
-static int receive_delay_probe(struct drbd_conf *mdev, struct p_header *h)
+static int receive_UnplugRemote(struct drbd_conf *mdev, struct p_header *h)
 {
-        struct p_delay_probe *p = (struct p_delay_probe *)h;
+        if (mdev->state.disk >= D_INCONSISTENT)
+                drbd_kick_lo(mdev);
 
-        ERR_IF(h->length != (sizeof(*p)-sizeof(*h))) return FALSE;
-        if (drbd_recv(mdev, h->payload, h->length) != h->length)
-                return FALSE;
+        /* Make sure we've acked all the TCP data associated
+         * with the data requests being unplugged */
+        drbd_tcp_quickack(mdev->data.socket);
 
-        got_delay_probe(mdev, USE_DATA_SOCKET, p);
         return TRUE;
 }
 
@@ -3695,7 +3620,7 @@ static drbd_cmd_handler_f drbd_default_handler[] = {
         [P_OV_REQUEST]      = receive_DataRequest,
         [P_OV_REPLY]        = receive_DataRequest,
         [P_CSUM_RS_REQUEST]    = receive_DataRequest,
-        [P_DELAY_PROBE]     = receive_delay_probe,
+        [P_DELAY_PROBE]     = receive_skip_silent,
         /* anything missing from this table is in
          * the asender_tbl, see get_asender_cmd */
         [P_MAX_CMD]         = NULL,
@@ -4472,11 +4397,9 @@ static int got_OVResult(struct drbd_conf *mdev, struct p_header *h)
         return TRUE;
 }
 
-static int got_delay_probe_m(struct drbd_conf *mdev, struct p_header *h)
+static int got_something_to_ignore_m(struct drbd_conf *mdev, struct p_header *h)
 {
-        struct p_delay_probe *p = (struct p_delay_probe *)h;
-
-        got_delay_probe(mdev, USE_META_SOCKET, p);
+        /* IGNORE */
         return TRUE;
 }
 
@@ -4504,7 +4427,7 @@ static struct asender_cmd *get_asender_cmd(int cmd)
         [P_BARRIER_ACK]     = { sizeof(struct p_barrier_ack), got_BarrierAck },
         [P_STATE_CHG_REPLY] = { sizeof(struct p_req_state_reply), got_RqSReply },
         [P_RS_IS_IN_SYNC]   = { sizeof(struct p_block_ack), got_IsInSync },
-        [P_DELAY_PROBE]     = { sizeof(struct p_delay_probe), got_delay_probe_m },
+        [P_DELAY_PROBE]     = { sizeof(struct p_delay_probe), got_something_to_ignore_m },
         [P_MAX_CMD]         = { 0, NULL },
         };
         if (cmd > P_MAX_CMD || asender_tbl[cmd].process == NULL)