made suggested changes

p2p/pex/addrbook.go

@@ -222,11 +222,12 @@ func (a *addrBook) IsGood(addr *p2p.NetAddress) bool {
 	return a.addrLookup[addr.ID].isOld()
 }
 
+// IsBanned returns true if the peer is currently banned
 func (a *addrBook) IsBanned(addr *p2p.NetAddress) bool {
 	a.mtx.Lock()
-	defer a.mtx.Unlock()
-
 	_, ok := a.badPeers[addr.ID]
+	a.mtx.Unlock()
+
 	return ok
 }
 
@@ -351,7 +352,7 @@ func (a *addrBook) ReinstateBadPeers() {
 			bucket := a.calcNewBucket(ka.Addr, ka.Src)
 			a.addToNewBucket(ka, bucket)
 			delete(a.badPeers, ka.ID())
-			a.Logger.Info("Reinstated Address", "addr", ka.Addr)
+			a.Logger.Info("Reinstated address", "addr", ka.Addr)
 		}
 	}
 }

p2p/pex/errors.go

@@ -64,6 +64,7 @@ func (err ErrAddrBookInvalidAddr) Error() string {
 	return fmt.Sprintf("Cannot add invalid address %v: %v", err.Addr, err.AddrErr)
 }
 
+// Err is thrown when the address is banned and therefore cannot be used
 type ErrAddressBanned struct {
 	Addr *p2p.NetAddress
 }

p2p/pex/pex_reactor.go

@@ -534,10 +534,6 @@ func (r *Reactor) dialAttemptsInfo(addr *p2p.NetAddress) (attempts int, lastDial
 func (r *Reactor) dialPeer(addr *p2p.NetAddress) error {
 	attempts, lastDialed := r.dialAttemptsInfo(addr)
 	if !r.Switch.IsPeerPersistent(addr) && attempts > maxAttemptsToDial {
-		// TODO(melekes): have a blacklist in the addrbook with peers whom we've
-		// failed to connect to. Then we can clean up attemptsToDial, which acts as
-		// a blacklist currently.
-		// https://github.com/tendermint/tendermint/issues/3572
 		r.book.MarkBad(addr, defaultBanTime)
 		return errMaxAttemptsToDial{}
 	}