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>

drivers/infiniband/hw/nes/nes_verbs.c

@@ -551,6 +551,7 @@ static int nes_dealloc_fmr(struct ib_fmr *ibfmr)
 	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 @@ static int nes_dealloc_fmr(struct ib_fmr *ibfmr)
 	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 @@ static int nes_dealloc_fmr(struct ib_fmr *ibfmr)
 		spin_unlock_irqrestore(&nesadapter->pbl_lock, flags);
 	}
 
-	return nes_dealloc_mw(&nesmr->ibmw);
+	return rc;
 }
 
 
@@ -1993,7 +1996,16 @@ static int nes_reg_mr(struct nes_device *nesdev, struct nes_pd *nespd,
 			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 @@ static int nes_dereg_mr(struct ib_mr *ib_mr)
 	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 @@ static int nes_dereg_mr(struct ib_mr *ib_mr)
 			" 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 @@ static int nes_dereg_mr(struct ib_mr *ib_mr)
 				" 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;
 }