IB/qib: Fix M_Key lease timeout handling

If a port has an M_Key lease set, the M_Key protect bits set to 1, and
a SubnSet arrives with an invalid M_Key, an M_Key mismatch trap is
generated, the lease timer begins as expected, and eventually the
M_Key protect bits will be set back to 0 as per the spec.  However, if
any other SMP with an invalid M_Key arrives, the lease timer is expired
and the M_Key protect bits remain in force.

This is not according to to spec.  In particular, C14-17 says that
a lease timer that is underway is not affected by protection level
checks (ie, at protection level 1, a SubnGet with a bad M_Key may be
successful, but does not stop the timer), and C14-19 says that the timer
shall stop when a valid M_Key has been received.  C14-19 is the only
compliance statement that specifies a stopping condition for the timer.

This behavior is magnified if the port's Master SM LID attribute
points at itself.  In that case, the M_Key mismatch trap is sufficient to
expire the timer, and the mkey lease attribute is rendered useless.
Reviewed-by: Ram Vepa <ram.vepa@qlogic.com>
Signed-off-by: Jim Foraker <foraker1@llnl.gov>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/qib/qib_mad.c

@@ -396,6 +396,7 @@ static int get_linkdowndefaultstate(struct qib_pportdata *ppd)
 
 static int check_mkey(struct qib_ibport *ibp, struct ib_smp *smp, int mad_flags)
 {
+	int valid_mkey = 0;
 	int ret = 0;
 
 	/* Is the mkey in the process of expiring? */
@@ -406,12 +407,25 @@ static int check_mkey(struct qib_ibport *ibp, struct ib_smp *smp, int mad_flags)
 		ibp->mkeyprot = 0;
 	}
 
-	/* M_Key checking depends on Portinfo:M_Key_protect_bits */
-	if ((mad_flags & IB_MAD_IGNORE_MKEY) == 0 && ibp->mkey != 0 &&
-	    ibp->mkey != smp->mkey &&
-	    (smp->method == IB_MGMT_METHOD_SET ||
-	     smp->method == IB_MGMT_METHOD_TRAP_REPRESS ||
-	     (smp->method == IB_MGMT_METHOD_GET && ibp->mkeyprot >= 2))) {
+	if ((mad_flags & IB_MAD_IGNORE_MKEY) ||  ibp->mkey == 0 ||
+	    ibp->mkey == smp->mkey)
+		valid_mkey = 1;
+
+	/* Unset lease timeout on any valid Get/Set/TrapRepress */
+	if (valid_mkey && ibp->mkey_lease_timeout &&
+	    (smp->method == IB_MGMT_METHOD_GET ||
+	     smp->method == IB_MGMT_METHOD_SET ||
+	     smp->method == IB_MGMT_METHOD_TRAP_REPRESS))
+		ibp->mkey_lease_timeout = 0;
+
+	if (!valid_mkey) {
+		switch (smp->method) {
+		case IB_MGMT_METHOD_GET:
+			/* Bad mkey not a violation below level 2 */
+			if (ibp->mkeyprot < 2)
+				break;
+		case IB_MGMT_METHOD_SET:
+		case IB_MGMT_METHOD_TRAP_REPRESS:
 			if (ibp->mkey_violations != 0xFFFF)
 				++ibp->mkey_violations;
 			if (!ibp->mkey_lease_timeout && ibp->mkey_lease_period)
@@ -420,8 +434,8 @@ static int check_mkey(struct qib_ibport *ibp, struct ib_smp *smp, int mad_flags)
 			/* Generate a trap notice. */
 			qib_bad_mkey(ibp, smp);
 			ret = IB_MAD_RESULT_SUCCESS | IB_MAD_RESULT_CONSUMED;
-	} else if (ibp->mkey_lease_timeout)
-		ibp->mkey_lease_timeout = 0;
+		}
+	}
 
 	return ret;
 }