RDMA/nes: Account for freed PBL after HW operation

Fix occurrences where the software PBL counts were changed before the
hardware was updated.  This bug allowed another thread to overallocate
the hardware resources.

Add proper PBL accounting in case nes_reg_mr() fails.

Signed-off-by: Don Wood <donald.e.wood@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/nes/nes_verbs.c b/drivers/infiniband/hw/nes/nes_verbs.c
index 4fdb7245..e666813 100644
--- a/drivers/infiniband/hw/nes/nes_verbs.c
+++ b/drivers/infiniband/hw/nes/nes_verbs.c
@@ -551,6 +551,7 @@
 	struct nes_device *nesdev = nesvnic->nesdev;
 	struct nes_adapter *nesadapter = nesdev->nesadapter;
 	int i = 0;
+	int rc;
 
 	/* free the resources */
 	if (nesfmr->leaf_pbl_cnt == 0) {
@@ -572,7 +573,9 @@
 	nesmr->ibmw.rkey = ibfmr->rkey;
 	nesmr->ibmw.uobject = NULL;
 
-	if (nesfmr->nesmr.pbls_used != 0) {
+	rc = nes_dealloc_mw(&nesmr->ibmw);
+
+	if ((rc == 0) && (nesfmr->nesmr.pbls_used != 0)) {
 		spin_lock_irqsave(&nesadapter->pbl_lock, flags);
 		if (nesfmr->nesmr.pbl_4k) {
 			nesadapter->free_4kpbl += nesfmr->nesmr.pbls_used;
@@ -584,7 +587,7 @@
 		spin_unlock_irqrestore(&nesadapter->pbl_lock, flags);
 	}
 
-	return nes_dealloc_mw(&nesmr->ibmw);
+	return rc;
 }
 
 
@@ -1993,7 +1996,16 @@
 			stag, ret, cqp_request->major_code, cqp_request->minor_code);
 	major_code = cqp_request->major_code;
 	nes_put_cqp_request(nesdev, cqp_request);
-
+	if ((!ret || major_code) && pbl_count != 0) {
+		spin_lock_irqsave(&nesadapter->pbl_lock, flags);
+		if (pbl_count > 1)
+			nesadapter->free_4kpbl += pbl_count+1;
+		else if (residual_page_count > 32)
+			nesadapter->free_4kpbl += pbl_count;
+		else
+			nesadapter->free_256pbl += pbl_count;
+		spin_unlock_irqrestore(&nesadapter->pbl_lock, flags);
+	}
 	if (!ret)
 		return -ETIME;
 	else if (major_code)
@@ -2607,24 +2619,6 @@
 	cqp_request->waiting = 1;
 	cqp_wqe = &cqp_request->cqp_wqe;
 
-	spin_lock_irqsave(&nesadapter->pbl_lock, flags);
-	if (nesmr->pbls_used != 0) {
-		if (nesmr->pbl_4k) {
-			nesadapter->free_4kpbl += nesmr->pbls_used;
-			if (nesadapter->free_4kpbl > nesadapter->max_4kpbl) {
-				printk(KERN_ERR PFX "free 4KB PBLs(%u) has exceeded the max(%u)\n",
-						nesadapter->free_4kpbl, nesadapter->max_4kpbl);
-			}
-		} else {
-			nesadapter->free_256pbl += nesmr->pbls_used;
-			if (nesadapter->free_256pbl > nesadapter->max_256pbl) {
-				printk(KERN_ERR PFX "free 256B PBLs(%u) has exceeded the max(%u)\n",
-						nesadapter->free_256pbl, nesadapter->max_256pbl);
-			}
-		}
-	}
-
-	spin_unlock_irqrestore(&nesadapter->pbl_lock, flags);
 	nes_fill_init_cqp_wqe(cqp_wqe, nesdev);
 	set_wqe_32bit_value(cqp_wqe->wqe_words, NES_CQP_WQE_OPCODE_IDX,
 			NES_CQP_DEALLOCATE_STAG | NES_CQP_STAG_VA_TO |
@@ -2642,11 +2636,6 @@
 			" CQP Major:Minor codes = 0x%04X:0x%04X\n",
 			ib_mr->rkey, ret, cqp_request->major_code, cqp_request->minor_code);
 
-	nes_free_resource(nesadapter, nesadapter->allocated_mrs,
-			(ib_mr->rkey & 0x0fffff00) >> 8);
-
-	kfree(nesmr);
-
 	major_code = cqp_request->major_code;
 	minor_code = cqp_request->minor_code;
 
@@ -2662,8 +2651,33 @@
 				" to destroy STag, ib_mr=%p, rkey = 0x%08X\n",
 				major_code, minor_code, ib_mr, ib_mr->rkey);
 		return -EIO;
-	} else
-		return 0;
+	}
+
+	if (nesmr->pbls_used != 0) {
+		spin_lock_irqsave(&nesadapter->pbl_lock, flags);
+		if (nesmr->pbl_4k) {
+			nesadapter->free_4kpbl += nesmr->pbls_used;
+			if (nesadapter->free_4kpbl > nesadapter->max_4kpbl)
+				printk(KERN_ERR PFX "free 4KB PBLs(%u) has "
+					"exceeded the max(%u)\n",
+					nesadapter->free_4kpbl,
+					nesadapter->max_4kpbl);
+		} else {
+			nesadapter->free_256pbl += nesmr->pbls_used;
+			if (nesadapter->free_256pbl > nesadapter->max_256pbl)
+				printk(KERN_ERR PFX "free 256B PBLs(%u) has "
+					"exceeded the max(%u)\n",
+					nesadapter->free_256pbl,
+					nesadapter->max_256pbl);
+		}
+		spin_unlock_irqrestore(&nesadapter->pbl_lock, flags);
+	}
+	nes_free_resource(nesadapter, nesadapter->allocated_mrs,
+			(ib_mr->rkey & 0x0fffff00) >> 8);
+
+	kfree(nesmr);
+
+	return 0;
 }