RDMA/cxgb3: Correctly serialize peer abort path

Open MPI and other stress testing exposed a few bad bugs in handling
aborts in the middle of a normal close.  Fix these by:

 - serializing abort reply and peer abort processing with disconnect
   processing

 - warning (and ignoring) if ep timer is stopped when it wasn't running

 - cleaning up disconnect path to correctly deal with aborting and
   dead endpoints

 - in iwch_modify_qp(), taking a ref on the ep before releasing the qp
   lock if iwch_ep_disconnect() will be called.  The ref is dropped
   after calling disconnect.

Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

3 files changed, 72 insertions, 35 deletions

diff --git a/drivers/infiniband/hw/cxgb3/iwch_cm.c b/drivers/infiniband/hw/cxgb3/iwch_cm.c
index 72ca360c3dbc..0b515d899f6c 100644
--- a/drivers/infiniband/hw/cxgb3/iwch_cm.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_cm.c
@@ -125,6 +125,12 @@ static void start_ep_timer(struct iwch_ep *ep)
 static void stop_ep_timer(struct iwch_ep *ep)
 {
         PDBG("%s ep %p\n", __func__, ep);
+        if (!timer_pending(&ep->timer)) {
+                printk(KERN_ERR "%s timer stopped when its not running!  ep %p state %u\n",
+                        __func__, ep, ep->com.state);
+                WARN_ON(1);
+                return;
+        }
         del_timer_sync(&ep->timer);
         put_ep(&ep->com);
 }
@@ -1083,8 +1089,11 @@ static int tx_ack(struct t3cdev *tdev, struct sk_buff *skb, void *ctx)
 static int abort_rpl(struct t3cdev *tdev, struct sk_buff *skb, void *ctx)
 {
         struct iwch_ep *ep = ctx;
+        unsigned long flags;
+        int release = 0;
 
         PDBG("%s ep %p\n", __func__, ep);
+        BUG_ON(!ep);
 
         /*
          * We get 2 abort replies from the HW.  The first one must
@@ -1095,9 +1104,22 @@ static int abort_rpl(struct t3cdev *tdev, struct sk_buff *skb, void *ctx)
                 return CPL_RET_BUF_DONE;
         }
 
-        close_complete_upcall(ep);
-        state_set(&ep->com, DEAD);
-        release_ep_resources(ep);
+        spin_lock_irqsave(&ep->com.lock, flags);
+        switch (ep->com.state) {
+        case ABORTING:
+                close_complete_upcall(ep);
+                __state_set(&ep->com, DEAD);
+                release = 1;
+                break;
+        default:
+                printk(KERN_ERR "%s ep %p state %d\n",
+                     __func__, ep, ep->com.state);
+                break;
+        }
+        spin_unlock_irqrestore(&ep->com.lock, flags);
+
+        if (release)
+                release_ep_resources(ep);
         return CPL_RET_BUF_DONE;
 }
 
@@ -1470,7 +1492,8 @@ static int peer_abort(struct t3cdev *tdev, struct sk_buff *skb, void *ctx)
         struct sk_buff *rpl_skb;
         struct iwch_qp_attributes attrs;
         int ret;
-        int state;
+        int release = 0;
+        unsigned long flags;
 
         if (is_neg_adv_abort(req->status)) {
                 PDBG("%s neg_adv_abort ep %p tid %d\n", __func__, ep,
@@ -1488,9 +1511,9 @@ static int peer_abort(struct t3cdev *tdev, struct sk_buff *skb, void *ctx)
                 return CPL_RET_BUF_DONE;
         }
 
-        state = state_read(&ep->com);
-        PDBG("%s ep %p state %u\n", __func__, ep, state);
-        switch (state) {
+        spin_lock_irqsave(&ep->com.lock, flags);
+        PDBG("%s ep %p state %u\n", __func__, ep, ep->com.state);
+        switch (ep->com.state) {
         case CONNECTING:
                 break;
         case MPA_REQ_WAIT:
@@ -1536,21 +1559,25 @@ static int peer_abort(struct t3cdev *tdev, struct sk_buff *skb, void *ctx)
                 break;
         case DEAD:
                 PDBG("%s PEER_ABORT IN DEAD STATE!!!!\n", __func__);
+                spin_unlock_irqrestore(&ep->com.lock, flags);
                 return CPL_RET_BUF_DONE;
         default:
                 BUG_ON(1);
                 break;
         }
         dst_confirm(ep->dst);
+        if (ep->com.state != ABORTING) {
+                __state_set(&ep->com, DEAD);
+                release = 1;
+        }
+        spin_unlock_irqrestore(&ep->com.lock, flags);
 
         rpl_skb = get_skb(skb, sizeof(*rpl), GFP_KERNEL);
         if (!rpl_skb) {
                 printk(KERN_ERR MOD "%s - cannot allocate skb!\n",
                        __func__);
-                dst_release(ep->dst);
-                l2t_release(L2DATA(ep->com.tdev), ep->l2t);
-                put_ep(&ep->com);
-                return CPL_RET_BUF_DONE;
+                release = 1;
+                goto out;
         }
         rpl_skb->priority = CPL_PRIORITY_DATA;
         rpl = (struct cpl_abort_rpl *) skb_put(rpl_skb, sizeof(*rpl));
@@ -1559,10 +1586,9 @@ static int peer_abort(struct t3cdev *tdev, struct sk_buff *skb, void *ctx)
         OPCODE_TID(rpl) = htonl(MK_OPCODE_TID(CPL_ABORT_RPL, ep->hwtid));
         rpl->cmd = CPL_ABORT_NO_RST;
         cxgb3_ofld_send(ep->com.tdev, rpl_skb);
-        if (state != ABORTING) {
-                state_set(&ep->com, DEAD);
+out:
+        if (release)
                 release_ep_resources(ep);
-        }
         return CPL_RET_BUF_DONE;
 }
 
@@ -1661,15 +1687,18 @@ static void ep_timeout(unsigned long arg)
         struct iwch_ep *ep = (struct iwch_ep *)arg;
         struct iwch_qp_attributes attrs;
         unsigned long flags;
+        int abort = 1;
 
         spin_lock_irqsave(&ep->com.lock, flags);
         PDBG("%s ep %p tid %u state %d\n", __func__, ep, ep->hwtid,
              ep->com.state);
         switch (ep->com.state) {
         case MPA_REQ_SENT:
+                __state_set(&ep->com, ABORTING);
                 connect_reply_upcall(ep, -ETIMEDOUT);
                 break;
         case MPA_REQ_WAIT:
+                __state_set(&ep->com, ABORTING);
                 break;
         case CLOSING:
         case MORIBUND:
@@ -1679,13 +1708,17 @@ static void ep_timeout(unsigned long arg)
                                      ep->com.qp, IWCH_QP_ATTR_NEXT_STATE,
                                      &attrs, 1);
                 }
+                __state_set(&ep->com, ABORTING);
                 break;
         default:
-                BUG();
+                printk(KERN_ERR "%s unexpected state ep %p state %u\n",
+                        __func__, ep, ep->com.state);
+                WARN_ON(1);
+                abort = 0;
         }
-        __state_set(&ep->com, CLOSING);
         spin_unlock_irqrestore(&ep->com.lock, flags);
-        abort_connection(ep, NULL, GFP_ATOMIC);
+        if (abort)
+                abort_connection(ep, NULL, GFP_ATOMIC);
         put_ep(&ep->com);
 }
 
@@ -1968,40 +2001,39 @@ int iwch_ep_disconnect(struct iwch_ep *ep, int abrupt, gfp_t gfp)
         PDBG("%s ep %p state %s, abrupt %d\n", __func__, ep,
              states[ep->com.state], abrupt);
 
-        if (ep->com.state == DEAD) {
-                PDBG("%s already dead ep %p\n", __func__, ep);
-                goto out;
-        }
-
-        if (abrupt) {
-                if (ep->com.state != ABORTING) {
-                        ep->com.state = ABORTING;
-                        close = 1;
-                }
-                goto out;
-        }
-
         switch (ep->com.state) {
         case MPA_REQ_WAIT:
         case MPA_REQ_SENT:
         case MPA_REQ_RCVD:
         case MPA_REP_SENT:
         case FPDU_MODE:
-                start_ep_timer(ep);
-                ep->com.state = CLOSING;
                 close = 1;
+                if (abrupt)
+                        ep->com.state = ABORTING;
+                else {
+                        ep->com.state = CLOSING;
+                        start_ep_timer(ep);
+                }
                 break;
         case CLOSING:
-                ep->com.state = MORIBUND;
                 close = 1;
+                if (abrupt) {
+                        stop_ep_timer(ep);
+                        ep->com.state = ABORTING;
+                } else
+                        ep->com.state = MORIBUND;
                 break;
         case MORIBUND:
+        case ABORTING:
+        case DEAD:
+                PDBG("%s ignoring disconnect ep %p state %u\n",
+                     __func__, ep, ep->com.state);
                 break;
         default:
                 BUG();
                 break;
         }
-out:
+
         spin_unlock_irqrestore(&ep->com.lock, flags);
         if (close) {
                 if (abrupt)
diff --git a/drivers/infiniband/hw/cxgb3/iwch_cm.h b/drivers/infiniband/hw/cxgb3/iwch_cm.h
index 2bb7fbdb3ff4..a2f1b787d970 100644
--- a/drivers/infiniband/hw/cxgb3/iwch_cm.h
+++ b/drivers/infiniband/hw/cxgb3/iwch_cm.h
@@ -56,6 +56,7 @@
 #define put_ep(ep) { \
         PDBG("put_ep (via %s:%u) ep %p refcnt %d\n", __func__, __LINE__,  \
              ep, atomic_read(&((ep)->kref.refcount))); \
+        WARN_ON(atomic_read(&((ep)->kref.refcount)) < 1); \
         kref_put(&((ep)->kref), __free_ep); \
 }
 
diff --git a/drivers/infiniband/hw/cxgb3/iwch_qp.c b/drivers/infiniband/hw/cxgb3/iwch_qp.c
index 8891c3b0a3d5..6cd484e11c11 100644
--- a/drivers/infiniband/hw/cxgb3/iwch_qp.c
+++ b/drivers/infiniband/hw/cxgb3/iwch_qp.c
@@ -832,6 +832,7 @@ int iwch_modify_qp(struct iwch_dev *rhp, struct iwch_qp *qhp,
                                 abort=0;
                                 disconnect = 1;
                                 ep = qhp->ep;
+                                get_ep(&ep->com);
                         }
                         flush_qp(qhp, &flag);
                         break;
@@ -848,6 +849,7 @@ int iwch_modify_qp(struct iwch_dev *rhp, struct iwch_qp *qhp,
                                 abort=1;
                                 disconnect = 1;
                                 ep = qhp->ep;
+                                get_ep(&ep->com);
                         }
                         goto err;
                         break;
@@ -929,8 +931,10 @@ out:
          * on the EP.  This can be a normal close (RTS->CLOSING) or
          * an abnormal close (RTS/CLOSING->ERROR).
          */
-        if (disconnect)
+        if (disconnect) {
                 iwch_ep_disconnect(ep, abort, GFP_KERNEL);
+                put_ep(&ep->com);
+        }
 
         /*
          * If free is 1, then we've disassociated the EP from the QP