[PATCH RFC 00/77] Re-design MSI/MSI-X interrupts enablement pattern

@@ -9051,26 +9051,28 @@ static void niu_try_msix(struct niu *np, u8 *ldg_num_map)
 		    (np->port == 0 ? 3 : 1));
 	BUG_ON(num_irqs > (NIU_NUM_LDG / parent->num_ports));
 
-retry:
+	err = pci_msix_table_size(pdev);
+	if (err < 0)
+		goto fail;
+
+	num_irqs = min(num_irqs, err);
 	for (i = 0; i < num_irqs; i++) {
 		msi_vec[i].vector = 0;
 		msi_vec[i].entry = i;
 	}
 
 	err = pci_enable_msix(pdev, msi_vec, num_irqs);
-	if (err < 0) {
-		np->flags &= ~NIU_FLAGS_MSIX;
-		return;
-	}
-	if (err > 0) {
-		num_irqs = err;
-		goto retry;
-	}
+	if (err)
+		goto fail;
 
 	np->flags |= NIU_FLAGS_MSIX;
 	for (i = 0; i < num_irqs; i++)
 		np->ldg[i].irq = msi_vec[i].vector;
 	np->num_ldg = num_irqs;
+	return;
+
+fail:
+	np->flags &= ~NIU_FLAGS_MSIX;
 }
 
 static int niu_n2_irq_init(struct niu *np, u8 *ldg_num_map)

@@ -854,17 +854,23 @@ static int mthca_enable_msi_x(struct mthca_dev *mdev)
 	struct msix_entry entries[3];
 	int err;
 
+	err = pci_msix_table_size(mdev->pdev);
+	if (err < 0)
+		return err;
+	if (err < ARRAY_SIZE(entries)) {
+		mthca_info(mdev, "Only %d MSI-X vectors available, "
+			   "not using MSI-X\n", err);
+
+		return -ENOSPC;
+	}
+
 	entries[0].entry = 0;
 	entries[1].entry = 1;
 	entries[2].entry = 2;
 
 	err = pci_enable_msix(mdev->pdev, entries, ARRAY_SIZE(entries));
-	if (err) {
-		if (err > 0)
-			mthca_info(mdev, "Only %d MSI-X vectors available, "
-				   "not using MSI-X\n", err);
+	if (err)
 		return err;
-	}
 
 	mdev->eq_table.eq[MTHCA_EQ_COMP ].msi_x_vector = entries[0].vector;
 	mdev->eq_table.eq[MTHCA_EQ_ASYNC].msi_x_vector = entries[1].vector;

@@ -377,19 +377,27 @@ static int vmci_enable_msix(struct pci_dev *pdev,
 {
 	int i;
 	int result;
+	int nvec;
 
-	for (i = 0; i < VMCI_MAX_INTRS; ++i) {
+	result = pci_msix_table_size(pdev);
+	if (result < 0)
+		return result;
+
+	nvec = min(result, VMCI_MAX_INTRS);
+	if (nvec < VMCI_MAX_INTRS)
+		nvec = 1;
+
+	for (i = 0; i < nvec; ++i) {
 		vmci_dev->msix_entries[i].entry = i;
 		vmci_dev->msix_entries[i].vector = i;
 	}
 
-	result = pci_enable_msix(pdev, vmci_dev->msix_entries, VMCI_MAX_INTRS);
-	if (result == 0)
-		vmci_dev->exclusive_vectors = true;
-	else if (result > 0)
-		result = pci_enable_msix(pdev, vmci_dev->msix_entries, 1);
+	result = pci_enable_msix(pdev, vmci_dev->msix_entries, nvec);
+	if (result)
+		return result;
 
-	return result;
+	vmci_dev->exclusive_vectors = true;
+	return 0;
 }
 
 /*

@@ -2836,16 +2836,20 @@ qla24xx_enable_msix(struct qla_hw_data *ha, struct rsp_que *rsp)
 	for (i = 0; i < ha->msix_count; i++)
 		entries[i].entry = i;
 
-	ret = pci_enable_msix(ha->pdev, entries, ha->msix_count);
-	if (ret) {
+	ret = pci_msix_table_size(ha->pdev);
+	if (ret < 0) {
+		goto msix_failed;
+	} else {
 		if (ret < MIN_MSIX_COUNT)
 			goto msix_failed;
 
-		ql_log(ql_log_warn, vha, 0x00c6,
-		    "MSI-X: Failed to enable support "
-		    "-- %d/%d\n Retry with %d vectors.\n",
-		    ha->msix_count, ret, ret);
-		ha->msix_count = ret;
+		if (ret < ha->msix_count) {
+			ql_log(ql_log_warn, vha, 0x00c6,
+			    "MSI-X: Failed to enable support "
+			    "-- %d/%d\n Retry with %d vectors.\n",
+			    ha->msix_count, ret, ret);
+			ha->msix_count = ret;
+		}
 		ret = pci_enable_msix(ha->pdev, entries, ha->msix_count);
 		if (ret) {
 msix_failed:

@@ -3727,18 +3727,16 @@ static int megasas_init_fw(struct megasas_instance *instance)
 					     (unsigned int)num_online_cpus());
 		for (i = 0; i < instance->msix_vectors; i++)
 			instance->msixentry[i].entry = i;
-		i = pci_enable_msix(instance->pdev, instance->msixentry,
-				    instance->msix_vectors);
-		if (i >= 0) {
-			if (i) {
-				if (!pci_enable_msix(instance->pdev,
-						     instance->msixentry, i))
-					instance->msix_vectors = i;
-				else
-					instance->msix_vectors = 0;
-			}
-		} else
+		i = pci_msix_table_size(instance->pdev);
+		if (i < 0) {
 			instance->msix_vectors = 0;
+		} else {
+			if (!pci_enable_msix(instance->pdev,
+					     instance->msixentry, i))
+				instance->msix_vectors = i;
+			else
+				instance->msix_vectors = 0;
+		}
 
 		dev_info(&instance->pdev->dev, "[scsi%d]: FW supports"
 			"<%d> MSIX vector,Online CPUs: <%d>,"

@@ -6202,25 +6202,26 @@ bnx2_enable_msix(struct bnx2 *bp, int msix_vecs)
 	 *  is setup properly */
 	BNX2_RD(bp, BNX2_PCI_MSIX_CONTROL);
 
-	for (i = 0; i < BNX2_MAX_MSIX_VEC; i++) {
-		msix_ent[i].entry = i;
-		msix_ent[i].vector = 0;
-	}
-
 	total_vecs = msix_vecs;
 #ifdef BCM_CNIC
 	total_vecs++;
 #endif
-	rc = -ENOSPC;
-	while (total_vecs >= BNX2_MIN_MSIX_VEC) {
-		rc = pci_enable_msix(bp->pdev, msix_ent, total_vecs);
-		if (rc <= 0)
-			break;
-		if (rc > 0)
-			total_vecs = rc;
+	rc = pci_msix_table_size(bp->pdev);
+	if (rc < 0)
+		return;
+
+	total_vecs = min(total_vecs, rc);
+	if (total_vecs < BNX2_MIN_MSIX_VEC)
+		return;
+
+	BUG_ON(total_vecs > ARRAY_SIZE(msix_ent));
+	for (i = 0; i < total_vecs; i++) {
+		msix_ent[i].entry = i;
+		msix_ent[i].vector = 0;
 	}
 
-	if (rc != 0)
+	rc = pci_enable_msix(bp->pdev, msix_ent, total_vecs);
+	if (rc)
 		return;
 
 	msix_vecs = total_vecs;

@@ -8639,13 +8639,17 @@ lpfc_sli4_enable_msix(struct lpfc_hba *phba)
 
 	/* Configure MSI-X capability structure */
 	vectors = phba->cfg_fcp_io_channel;
-enable_msix_vectors:
-	rc = pci_enable_msix(phba->pcidev, phba->sli4_hba.msix_entries,
-			     vectors);
-	if (rc > 1) {
-		vectors = rc;
-		goto enable_msix_vectors;
-	} else if (rc) {
+
+	rc = pci_msix_table_size(phba->pcidev);
+	if (rc < 0)
+		goto msg_fail_out;
+
+	vectors = min(vectors, rc);
+	if (vectors > 1)
+		rc = pci_enable_msix(phba->pcidev, phba->sli4_hba.msix_entries,
+				     vectors);
+	if (rc) {
+msg_fail_out:
 		lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
 				"0484 PCI enable MSI-X failed (%d)\n", rc);
 		goto vec_fail_out;

@@ -1852,8 +1852,16 @@ static void mlx4_enable_msi_x(struct mlx4_dev *dev)
 	int i;
 
 	if (msi_x) {
+		err = pci_msix_table_size(dev->pdev);
+		if (err < 0)
+			goto no_msi;
+
+		/* Try if at least 2 vectors are available */
 		nreq = min_t(int, dev->caps.num_eqs - dev->caps.reserved_eqs,
 			     nreq);
+		nreq = min_t(int, nreq, err);
+		if (nreq < 2)
+			goto no_msi;
 
 		entries = kcalloc(nreq, sizeof *entries, GFP_KERNEL);
 		if (!entries)

@@ -1862,17 +1870,8 @@ static void mlx4_enable_msi_x(struct mlx4_dev *dev)
 		for (i = 0; i < nreq; ++i)
 			entries[i].entry = i;
 
-	retry:
 		err = pci_enable_msix(dev->pdev, entries, nreq);
 		if (err) {
-			/* Try again if at least 2 vectors are available */
-			if (err > 1) {
-				mlx4_info(dev, "Requested %d vectors, "
-					  "but only %d MSI-X vectors available, "
-					  "trying again\n", nreq, err);
-				nreq = err;
-				goto retry;
-			}
 			kfree(entries);
 			goto no_msi;
 		}

@@ -4079,7 +4079,11 @@ static void cciss_interrupt_mode(ctlr_info_t *h)
 		goto default_int_mode;
 
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSIX)) {
-		err = pci_enable_msix(h->pdev, cciss_msix_entries, 4);
+		err = pci_msix_table_size(h->pdev);
+		if (err < ARRAY_SIZE(cciss_msix_entries))
+			goto default_int_mode;
+		err = pci_enable_msix(h->pdev, cciss_msix_entries,
+				      ARRAY_SIZE(cciss_msix_entries));
 		if (!err) {
 			h->intr[0] = cciss_msix_entries[0].vector;
 			h->intr[1] = cciss_msix_entries[1].vector;

@@ -4088,15 +4092,8 @@ static void cciss_interrupt_mode(ctlr_info_t *h)
 			h->msix_vector = 1;
 			return;
 		}
-		if (err > 0) {
-			dev_warn(&h->pdev->dev,
-				"only %d MSI-X vectors available\n", err);
-			goto default_int_mode;
-		} else {
-			dev_warn(&h->pdev->dev,
-				"MSI-X init failed %d\n", err);
-			goto default_int_mode;
-		}
+		dev_warn(&h->pdev->dev, "MSI-X init failed %d\n", err);
+		goto default_int_mode;
 	}
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSI)) {
 		if (!pci_enable_msi(h->pdev))

@@ -4680,24 +4680,23 @@ pmcraid_register_interrupt_handler(struct pmcraid_instance *pinstance)
 
 	if ((pmcraid_enable_msix) &&
 		(pci_find_capability(pdev, PCI_CAP_ID_MSIX))) {
-		int num_hrrq = PMCRAID_NUM_MSIX_VECTORS;
 		struct msix_entry entries[PMCRAID_NUM_MSIX_VECTORS];
+		int num_hrrq = ARRAY_SIZE(entries);
 		int i;
-		for (i = 0; i < PMCRAID_NUM_MSIX_VECTORS; i++)
-			entries[i].entry = i;
-
-		rc = pci_enable_msix(pdev, entries, num_hrrq);
-		if (rc < 0)
-			goto pmcraid_isr_legacy;
 
 		/* Check how many MSIX vectors are allocated and register
 		 * msi-x handlers for each of them giving appropriate buffer
 		 */
-		if (rc > 0) {
-			num_hrrq = rc;
-			if (pci_enable_msix(pdev, entries, num_hrrq))
-				goto pmcraid_isr_legacy;
-		}
+		rc = pci_msix_table_size(pdev);
+		if (rc < 0)
+			goto pmcraid_isr_legacy;
+
+		num_hrrq = min(num_hrrq, rc);
+		for (i = 0; i < num_hrrq; i++)
+			entries[i].entry = i;
+
+		if (pci_enable_msix(pdev, entries, num_hrrq))
+			goto pmcraid_isr_legacy;
 
 		for (i = 0; i < num_hrrq; i++) {
 			pinstance->hrrq_vector[i].hrrq_id = i;

@@ -512,6 +512,16 @@ csio_enable_msix(struct csio_hw *hw)
 	if (hw->flags & CSIO_HWF_USING_SOFT_PARAMS || !csio_is_hw_master(hw))
 		cnt = min_t(uint8_t, hw->cfg_niq, cnt);
 
+	rv = pci_msix_table_size(hw->pdev);
+	if (rv < 0)
+		return rv;
+
+	cnt = min(cnt, rv);
+	if (cnt < min) {
+		csio_info(hw, "Not using MSI-X, remainder:%d\n", rv);
+		return -ENOSPC;
+	}
+
 	entries = kzalloc(sizeof(struct msix_entry) * cnt, GFP_KERNEL);
 	if (!entries)
 		return -ENOMEM;

@@ -521,19 +531,15 @@ csio_enable_msix(struct csio_hw *hw)
 
 	csio_dbg(hw, "FW supp #niq:%d, trying %d msix's\n", hw->cfg_niq, cnt);
 
-	while ((rv = pci_enable_msix(hw->pdev, entries, cnt)) >= min)
-		cnt = rv;
+	rv = pci_enable_msix(hw->pdev, entries, cnt);
 	if (!rv) {
 		if (cnt < (hw->num_sqsets + extra)) {
 			csio_dbg(hw, "Reducing sqsets to %d\n", cnt - extra);
 			csio_reduce_sqsets(hw, cnt - extra);
 		}
 	} else {
-		if (rv > 0)
-			csio_info(hw, "Not using MSI-X, remainder:%d\n", rv);
-
 		kfree(entries);
-		return -ENOSPC;
+		return rv;
 	}
 
 	/* Save off vectors */

@@ -3090,25 +3090,26 @@ static int cxgb_enable_msix(struct adapter *adap)
 	int vectors;
 	int i, err;
 
-	vectors = ARRAY_SIZE(entries);
+	err = pci_msix_table_size(adap->pdev);
+	if (err < 0)
+		return err;
+
+	vectors = min_t(int, err, ARRAY_SIZE(entries));
+	if (vectors < (adap->params.nports + 1))
+		return -ENOSPC;
+
 	for (i = 0; i < vectors; ++i)
 		entries[i].entry = i;
 
-	while ((err = pci_enable_msix(adap->pdev, entries, vectors)) > 0)
-		vectors = err;
-
-	if (!err && vectors < (adap->params.nports + 1)) {
-		pci_disable_msix(adap->pdev);
-		err = -ENOSPC;
-	}
+	err = pci_enable_msix(adap->pdev, entries, vectors);
+	if (err)
+		return err;
 
-	if (!err) {
-		for (i = 0; i < vectors; ++i)
-			adap->msix_info[i].vec = entries[i].vector;
-		adap->msix_nvectors = vectors;
-	}
+	for (i = 0; i < vectors; ++i)
+		adap->msix_info[i].vec = entries[i].vector;
+	adap->msix_nvectors = vectors;
 
-	return err;
+	return 0;
 }
 
 static void print_port_info(struct adapter *adap, const struct adapter_info *ai)

@@ -119,8 +119,13 @@ static int mlx5_enable_msix(struct mlx5_core_dev *dev)
 	int err;
 	int i;
 
+	err = pci_msix_table_size(dev->pdev);
+	if (err < 0)
+		return err;
+
 	nvec = dev->caps.num_ports * num_online_cpus() + MLX5_EQ_VEC_COMP_BASE;
 	nvec = min_t(int, nvec, num_eqs);
+	nvec = min_t(int, nvec, err);
 	if (nvec <= MLX5_EQ_VEC_COMP_BASE)
 		return -ENOSPC;
 

@@ -131,20 +136,15 @@ static int mlx5_enable_msix(struct mlx5_core_dev *dev)
 	for (i = 0; i < nvec; i++)
 		table->msix_arr[i].entry = i;
 
-retry:
-	table->num_comp_vectors = nvec - MLX5_EQ_VEC_COMP_BASE;
 	err = pci_enable_msix(dev->pdev, table->msix_arr, nvec);
-	if (err <= 0) {
+	if (err) {
+		kfree(table->msix_arr);
 		return err;
-	} else if (err > MLX5_EQ_VEC_COMP_BASE) {
-		nvec = err;
-		goto retry;
 	}
 
-	mlx5_core_dbg(dev, "received %d MSI vectors out of %d requested\n", err, nvec);
-	kfree(table->msix_arr);
+	table->num_comp_vectors = nvec - MLX5_EQ_VEC_COMP_BASE;
 
-	return -ENOSPC;
+	return 0;
 }
 
 static void mlx5_disable_msix(struct mlx5_core_dev *dev)

@@ -1091,6 +1091,14 @@ static inline void ahci_gtf_filter_workaround(struct ata_host *host)
 {}
 #endif
 
+static int ahci_get_mrsm(struct ahci_host_priv *hpriv)
+{
+	void __iomem *mmio = hpriv->mmio;
+	u32 ctl = readl(mmio + HOST_CTL);
+
+	return ctl & HOST_MRSM;
+}
+
 int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
 			 struct ahci_host_priv *hpriv)
 {

@@ -1116,6 +1124,15 @@ int ahci_init_interrupts(struct pci_dev *pdev, unsigned int n_ports,
 	if (rc)
 		goto intx;
 
+	/*
+	 * Fallback to single MSI mode if the controller enforced MRSM mode 
+	 */
+	if (ahci_get_mrsm(hpriv)) {
+		pci_disable_msi(pdev);
+		printk(KERN_INFO "ahci: MRSM is on, fallback to single MSI\n");
+		goto single_msi;
+	}
+
 	return nvec;
 
 single_msi:

@@ -91,6 +91,7 @@ enum {
 	/* HOST_CTL bits */
 	HOST_RESET		= (1 << 0),  /* reset controller; self-clear */
 	HOST_IRQ_EN		= (1 << 1),  /* global IRQ enable */
+	HOST_MRSM		= (1 << 2),  /* MSI Revert to Single Message */
 	HOST_AHCI_EN		= (1 << 31), /* AHCI enabled */
 
 	/* HOST_CAP bits */

@@ -1749,8 +1749,7 @@ void ixgbevf_reset(struct ixgbevf_adapter *adapter)
 static int ixgbevf_acquire_msix_vectors(struct ixgbevf_adapter *adapter,
 					int vectors)
 {
-	int err = 0;
-	int vector_threshold;
+	int err, vector_threshold;
 
 	/* We'll want at least 2 (vector_threshold):
 	 * 1) TxQ[0] + RxQ[0] handler

@@ -1763,18 +1762,15 @@ static int ixgbevf_acquire_msix_vectors(struct ixgbevf_adapter *adapter,
 	 * Right now, we simply care about how many we'll get; we'll
 	 * set them up later while requesting irq's.
 	 */
-	while (vectors >= vector_threshold) {
-		err = pci_enable_msix(adapter->pdev, adapter->msix_entries,
-				      vectors);
-		if (!err || err < 0) /* Success or a nasty failure. */
-			break;
-		else /* err == number of vectors we should try again with */
-			vectors = err;
-	}
+	err = pci_msix_table_size(adapter->pdev);
+	if (err < 0)
+		return err;
 
+	vectors = min(vectors, err);
 	if (vectors < vector_threshold)
-		err = -ENOSPC;
+		return -ENOSPC;
 
+	err = pci_enable_msix(adapter->pdev, adapter->msix_entries, vectors);
 	if (err) {
 		dev_err(&adapter->pdev->dev,
 			"Unable to allocate MSI-X interrupts\n");

@@ -734,6 +734,16 @@ static int tsi721_enable_msix(struct tsi721_device *priv)
 	int err;
 	int i;
 
+	err = pci_msix_table_size(priv->pdev);
+	if (err < 0)
+		goto err_out;
+	if (err < ARRAY_SIZE(entries)) {
+		dev_info(&priv->pdev->dev,
+			 "Only %d MSI-X vectors available, not using MSI-X\n",
+			 err);
+		return -ENOSPC;
+	}
+
 	entries[TSI721_VECT_IDB].entry = TSI721_MSIX_SR2PC_IDBQ_RCV(IDB_QUEUE);
 	entries[TSI721_VECT_PWRX].entry = TSI721_MSIX_SRIO_MAC_INT;
 

@@ -769,16 +779,8 @@ static int tsi721_enable_msix(struct tsi721_device *priv)
 #endif /* CONFIG_RAPIDIO_DMA_ENGINE */
 
 	err = pci_enable_msix(priv->pdev, entries, ARRAY_SIZE(entries));
-	if (err) {
-		if (err > 0)
-			dev_info(&priv->pdev->dev,
-				 "Only %d MSI-X vectors available, "
-				 "not using MSI-X\n", err);
-		else
-			dev_err(&priv->pdev->dev,
-				"Failed to enable MSI-X (err=%d)\n", err);
-		return err;
-	}
+	if (err)
+		goto err_out;
 
 	/*
 	 * Copy MSI-X vector information into tsi721 private structure

@@ -833,6 +835,11 @@ static int tsi721_enable_msix(struct tsi721_device *priv)
 #endif /* CONFIG_RAPIDIO_DMA_ENGINE */
 
 	return 0;
+
+err_out:
+	dev_err(&priv->pdev->dev,
+		"Failed to enable MSI-X (err=%d)\n", err);
+	return err;
 }
 #endif /* CONFIG_PCI_MSI */
 

@@ -1261,21 +1261,24 @@ static int efx_probe_interrupts(struct efx_nic *efx)
 		n_channels += extra_channels;
 		n_channels = min(n_channels, efx->max_channels);
 
-		for (i = 0; i < n_channels; i++)
-			xentries[i].entry = i;
-		rc = pci_enable_msix(efx->pci_dev, xentries, n_channels);
-		if (rc > 0) {
+		rc = pci_msix_table_size(efx->pci_dev);
+		if (rc < 0)
+			goto msi;
+
+		if (rc < n_channels) {
 			netif_err(efx, drv, efx->net_dev,
 				  "WARNING: Insufficient MSI-X vectors"
 				  " available (%d < %u).\n", rc, n_channels);
 			netif_err(efx, drv, efx->net_dev,
 				  "WARNING: Performance may be reduced.\n");
-			EFX_BUG_ON_PARANOID(rc >= n_channels);
 			n_channels = rc;
-			rc = pci_enable_msix(efx->pci_dev, xentries,
-					     n_channels);
 		}
 
+		EFX_BUG_ON_PARANOID(n_channels > ARRAY_SIZE(xentries));
+		for (i = 0; i < n_channels; i++)
+			xentries[i].entry = i;
+
+		rc = pci_enable_msix(efx->pci_dev, xentries, n_channels);
 		if (rc == 0) {
 			efx->n_channels = n_channels;
 			if (n_channels > extra_channels)

@@ -1293,6 +1296,7 @@ static int efx_probe_interrupts(struct efx_nic *efx)
 				efx_get_channel(efx, i)->irq =
 					xentries[i].vector;
 		} else {
+msi:
 			/* Fall back to single channel MSI */
 			efx->interrupt_mode = EFX_INT_MODE_MSI;
 			netif_err(efx, drv, efx->net_dev,

@@ -11241,6 +11241,10 @@ static bool tg3_enable_msix(struct tg3 *tp)
 	int i, rc;
 	struct msix_entry msix_ent[TG3_IRQ_MAX_VECS];
 
+	rc = pci_msix_table_size(tp->pdev);
+	if (rc < 0)
+		return false;
+
 	tp->txq_cnt = tp->txq_req;
 	tp->rxq_cnt = tp->rxq_req;
 	if (!tp->rxq_cnt)

@@ -11256,6 +11260,14 @@ static bool tg3_enable_msix(struct tg3 *tp)
 		tp->txq_cnt = 1;
 
 	tp->irq_cnt = tg3_irq_count(tp);
+	if (tp->irq_cnt > rc) {
+		netdev_notice(tp->dev, "Requested %d MSI-Xs, available %d\n",
+			      tp->irq_cnt, rc);
+		tp->irq_cnt = rc;
+		tp->rxq_cnt = max(rc - 1, 1);
+		if (tp->txq_cnt)
+			tp->txq_cnt = min(tp->rxq_cnt, tp->txq_max);
+	}
 
 	for (i = 0; i < tp->irq_max; i++) {
 		msix_ent[i].entry  = i;

@@ -11263,18 +11275,8 @@ static bool tg3_enable_msix(struct tg3 *tp)
 	}
 
 	rc = pci_enable_msix(tp->pdev, msix_ent, tp->irq_cnt);
-	if (rc < 0) {
+	if (rc)
 		return false;
-	} else if (rc != 0) {
-		if (pci_enable_msix(tp->pdev, msix_ent, rc))
-			return false;
-		netdev_notice(tp->dev, "Requested %d MSI-X vectors, received %d\n",
-			      tp->irq_cnt, rc);
-		tp->irq_cnt = rc;
-		tp->rxq_cnt = max(rc - 1, 1);
-		if (tp->txq_cnt)
-			tp->txq_cnt = min(tp->rxq_cnt, tp->txq_max);
-	}
 
 	for (i = 0; i < tp->irq_max; i++)
 		tp->napi[i].irq_vec = msix_ent[i].vector;

@@ -1774,34 +1774,36 @@ static int nvme_setup_io_queues(struct nvme_dev *dev)
 	/* Deregister the admin queue's interrupt */
 	free_irq(dev->entry[0].vector, dev->queues[0]);
 
-	vecs = nr_io_queues;
+	result = pci_msix_table_size(pdev);
+	if (result < 0)
+		goto msi;
+
+	vecs = min(result, nr_io_queues);
 	for (i = 0; i < vecs; i++)
 		dev->entry[i].entry = i;
-	for (;;) {
-		result = pci_enable_msix(pdev, dev->entry, vecs);
-		if (result <= 0)
-			break;
-		vecs = result;
-	}
 
-	if (result < 0) {
-		vecs = nr_io_queues;
-		if (vecs > 32)
-			vecs = 32;
-		for (;;) {
-			result = pci_enable_msi_block(pdev, vecs);
-			if (result == 0) {
-				for (i = 0; i < vecs; i++)
-					dev->entry[i].vector = i + pdev->irq;
-				break;
-			} else if (result < 0) {
-				vecs = 1;
-				break;
-			}
-			vecs = result;
-		}
+	result = pci_enable_msix(pdev, dev->entry, vecs);
+	if (result == 0)
+		goto irq;
+
+ msi:
+	result = pci_get_msi_cap(pdev);
+	if (result < 0)
+		goto no_msi;
+
+	vecs = min(result, nr_io_queues);
+
+	result = pci_enable_msi_block(pdev, vecs);
+	if (result == 0) {
+		for (i = 0; i < vecs; i++)
+			dev->entry[i].vector = i + pdev->irq;
+		goto irq;
 	}
 
+ no_msi:
+	vecs = 1;
+
+ irq:
 	/*
 	 * Should investigate if there's a performance win from allocating
 	 * more queues than interrupt vectors; it might allow the submission

@@ -2297,7 +2297,21 @@ static int vxge_alloc_msix(struct vxgedev *vdev)
 	int msix_intr_vect = 0, temp;
 	vdev->intr_cnt = 0;
 
-start:
+	ret = pci_msix_table_size(vdev->pdev);
+	if (ret < 0)
+		goto alloc_entries_failed;
+
+	if (ret < (vdev->no_of_vpath * 2 + 1)) {
+		if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
+			ret = -ENOSPC;
+			goto alloc_entries_failed;
+		}
+		/* Try with less no of vector by reducing no of vpaths count */
+		temp = (ret - 1)/2;
+		vxge_close_vpaths(vdev, temp);
+		vdev->no_of_vpath = temp;
+	}
+
 	/* Tx/Rx MSIX Vectors count */
 	vdev->intr_cnt = vdev->no_of_vpath * 2;
 

@@ -2347,25 +2361,7 @@ start:
 	vdev->vxge_entries[j].in_use = 0;
 
 	ret = pci_enable_msix(vdev->pdev, vdev->entries, vdev->intr_cnt);
-	if (ret > 0) {
-		vxge_debug_init(VXGE_ERR,
-			"%s: MSI-X enable failed for %d vectors, ret: %d",
-			VXGE_DRIVER_NAME, vdev->intr_cnt, ret);
-		if ((max_config_vpath != VXGE_USE_DEFAULT) || (ret < 3)) {
-			ret = -ENOSPC;
-			goto enable_msix_failed;
-		}
-
-		kfree(vdev->entries);
-		kfree(vdev->vxge_entries);
-		vdev->entries = NULL;
-		vdev->vxge_entries = NULL;
-		/* Try with less no of vector by reducing no of vpaths count */
-		temp = (ret - 1)/2;
-		vxge_close_vpaths(vdev, temp);
-		vdev->no_of_vpath = temp;
-		goto start;
-	} else if (ret < 0)
+	if (ret)
 		goto enable_msix_failed;
 	return 0;
 

@@ -4103,34 +4103,32 @@ static void hpsa_interrupt_mode(struct ctlr_info *h)
 	int err, i;
 	struct msix_entry hpsa_msix_entries[MAX_REPLY_QUEUES];
 
-	for (i = 0; i < MAX_REPLY_QUEUES; i++) {
-		hpsa_msix_entries[i].vector = 0;
-		hpsa_msix_entries[i].entry = i;
-	}
-
 	/* Some boards advertise MSI but don't really support it */
 	if ((h->board_id == 0x40700E11) || (h->board_id == 0x40800E11) ||
 	    (h->board_id == 0x40820E11) || (h->board_id == 0x40830E11))
 		goto default_int_mode;
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSIX)) {
 		dev_info(&h->pdev->dev, "MSIX\n");
+
+		err = pci_msix_table_size(h->pdev);
+		if (err < ARRAY_SIZE(hpsa_msix_entries))
+			goto default_int_mode;
+
+		for (i = 0; i < ARRAY_SIZE(hpsa_msix_entries); i++) {
+			hpsa_msix_entries[i].vector = 0;
+			hpsa_msix_entries[i].entry = i;
+		}
+
 		err = pci_enable_msix(h->pdev, hpsa_msix_entries,
-						MAX_REPLY_QUEUES);
+				      ARRAY_SIZE(hpsa_msix_entries));
 		if (!err) {
 			for (i = 0; i < MAX_REPLY_QUEUES; i++)
 				h->intr[i] = hpsa_msix_entries[i].vector;
 			h->msix_vector = 1;
 			return;
 		}
-		if (err > 0) {
-			dev_warn(&h->pdev->dev, "only %d MSI-X vectors "
-			       "available\n", err);
-			goto default_int_mode;
-		} else {
-			dev_warn(&h->pdev->dev, "MSI-X init failed %d\n",
-			       err);
-			goto default_int_mode;
-		}
+		dev_warn(&h->pdev->dev, "MSI-X init failed %d\n", err);
+		goto default_int_mode;
 	}
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSI)) {
 		dev_info(&h->pdev->dev, "MSI\n");

@@ -2469,21 +2469,11 @@ bnad_enable_msix(struct bnad *bnad)
 	if (bnad->msix_table)
 		return;
 
-	bnad->msix_table =
-		kcalloc(bnad->msix_num, sizeof(struct msix_entry), GFP_KERNEL);
-
-	if (!bnad->msix_table)
+	ret = pci_msix_table_size(bnad->pcidev);
+	if (ret < 0)
 		goto intx_mode;
 
-	for (i = 0; i < bnad->msix_num; i++)
-		bnad->msix_table[i].entry = i;
-
-	ret = pci_enable_msix(bnad->pcidev, bnad->msix_table, bnad->msix_num);
-	if (ret > 0) {
-		/* Not enough MSI-X vectors. */
-		pr_warn("BNA: %d MSI-X vectors allocated < %d requested\n",
-			ret, bnad->msix_num);
-
+	if (ret < bnad->msix_num) {
 		spin_lock_irqsave(&bnad->bna_lock, flags);
 		/* ret = #of vectors that we got */
 		bnad_q_num_adjust(bnad, (ret - BNAD_MAILBOX_MSIX_VECTORS) / 2,