OS-7184 IPMP broken by OS-4683 (#261)

Reviewed by: Jason King <jbk@joyent.com>
Reviewed by: Cody Mello <melloc@writev.io>
Approved by: Mike Zeller <mike.zeller@joyent.com>

usr/src/uts/common/inet/ip.h

@@ -1730,8 +1730,6 @@ typedef struct ill_s {
 	 * Capabilities related fields.
 	 */
 	uint_t  ill_dlpi_capab_state;	/* State of capability query, IDCS_* */
-	kcondvar_t ill_dlpi_capab_cv;	/* CV for broadcasting state changes */
-	kmutex_t ill_dlpi_capab_lock;	/* Lock for accessing above Cond Var */
 	uint_t	ill_capab_pending_cnt;
 	uint64_t ill_capabilities;	/* Enabled capabilities, ILL_CAPAB_* */
 	ill_hcksum_capab_t *ill_hcksum_capab; /* H/W cksumming capabilities */

usr/src/uts/common/inet/ip/ip.c

@@ -4124,8 +4124,6 @@ ip_modclose(ill_t *ill)
 	rw_destroy(&ill->ill_mcast_lock);
 	mutex_destroy(&ill->ill_mcast_serializer);
 	list_destroy(&ill->ill_nce);
-	cv_destroy(&ill->ill_dlpi_capab_cv);
-	mutex_destroy(&ill->ill_dlpi_capab_lock);
 
 	/*
 	 * Now we are done with the module close pieces that

usr/src/uts/common/inet/ip/ip_if.c

@@ -1394,10 +1394,11 @@ ill_capability_wait(ill_t *ill)
 
 	while (ill->ill_capab_pending_cnt != 0 &&
 	    (ill->ill_state_flags & ILL_CONDEMNED) == 0) {
-		mutex_enter(&ill->ill_dlpi_capab_lock);
+		/* This may enable blocked callers of ill_capability_done(). */
 		ipsq_exit(ill->ill_phyint->phyint_ipsq);
-		cv_wait(&ill->ill_dlpi_capab_cv, &ill->ill_dlpi_capab_lock);
-		mutex_exit(&ill->ill_dlpi_capab_lock);
+		/* Pause a bit (1msec) before we re-enter the squeue. */
+		delay(drv_usectohz(1000000));
+
 		/*
 		 * If ipsq_enter() fails, someone set ILL_CONDEMNED
 		 * while we dropped the squeue. Indicate such to the caller.
@@ -3513,9 +3514,6 @@ ill_init_common(ill_t *ill, queue_t *q, boolean_t isv6, boolean_t is_loopback,
 	ill->ill_max_buf = ND_MAX_Q;
 	ill->ill_refcnt = 0;
 
-	cv_init(&ill->ill_dlpi_capab_cv, NULL, CV_DEFAULT, NULL);
-	mutex_init(&ill->ill_dlpi_capab_lock, NULL, MUTEX_DEFAULT, NULL);
-
 	return (0);
 }
 
@@ -12935,17 +12933,14 @@ void
 ill_capability_done(ill_t *ill)
 {
 	ASSERT(ill->ill_capab_pending_cnt != 0);
+	ASSERT(IAM_WRITER_ILL(ill));
 
 	ill_dlpi_done(ill, DL_CAPABILITY_REQ);
 
 	ill->ill_capab_pending_cnt--;
 	if (ill->ill_capab_pending_cnt == 0 &&
 	    ill->ill_dlpi_capab_state == IDCS_OK)
 		ill_capability_reset_alloc(ill);
-
-	mutex_enter(&ill->ill_dlpi_capab_lock);
-	cv_broadcast(&ill->ill_dlpi_capab_cv);
-	mutex_exit(&ill->ill_dlpi_capab_lock);
 }
 
 /*