netdev - [PATCH RFC 29/77] cxgb4vf: Update MSI/MSI-X interrupts enablement code

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Message-Id: <e4d21d117874dbbe4aac4618b3cc3e3d9d0cbeb6.1380703262.git.agordeev@redhat.com>
Date:	Wed,  2 Oct 2013 12:48:45 +0200
From:	Alexander Gordeev <agordeev@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Alexander Gordeev <agordeev@...hat.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Ralf Baechle <ralf@...ux-mips.org>,
	Michael Ellerman <michael@...erman.id.au>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Martin Schwidefsky <schwidefsky@...ibm.com>,
	Ingo Molnar <mingo@...hat.com>, Tejun Heo <tj@...nel.org>,
	Dan Williams <dan.j.williams@...el.com>,
	Andy King <acking@...are.com>, Jon Mason <jon.mason@...el.com>,
	Matt Porter <mporter@...nel.crashing.org>,
	linux-pci@...r.kernel.org, linux-mips@...ux-mips.org,
	linuxppc-dev@...ts.ozlabs.org, linux390@...ibm.com,
	linux-s390@...r.kernel.org, x86@...nel.org,
	linux-ide@...r.kernel.org, iss_storagedev@...com,
	linux-nvme@...ts.infradead.org, linux-rdma@...r.kernel.org,
	netdev@...r.kernel.org, e1000-devel@...ts.sourceforge.net,
	linux-driver@...gic.com,
	Solarflare linux maintainers <linux-net-drivers@...arflare.com>,
	"VMware, Inc." <pv-drivers@...are.com>, linux-scsi@...r.kernel.org
Subject: [PATCH RFC 29/77] cxgb4vf: Update MSI/MSI-X interrupts enablement code

As result of recent re-design of the MSI/MSI-X interrupts enabling
pattern this driver has to be updated to use the new technique to
obtain a optimal number of MSI/MSI-X interrupts required.

Signed-off-by: Alexander Gordeev <agordeev@...hat.com>
---
 .../net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c    |   49 ++++++++++++--------
 1 files changed, 29 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
index 11cbce1..48bb33b 100644
--- a/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
+++ b/drivers/net/ethernet/chelsio/cxgb4vf/cxgb4vf_main.c
@@ -2437,13 +2437,10 @@ static void reduce_ethqs(struct adapter *adapter, int n)
  */
 static int enable_msix(struct adapter *adapter)
 {
-	int i, err, want, need;
+	int i, err, want, need, nqsets;
 	struct msix_entry entries[MSIX_ENTRIES];
 	struct sge *s = &adapter->sge;
 
-	for (i = 0; i < MSIX_ENTRIES; ++i)
-		entries[i].entry = i;
-
 	/*
 	 * We _want_ enough MSI-X interrupts to cover all of our "Queue Sets"
 	 * plus those needed for our "extras" (for example, the firmware
@@ -2453,26 +2450,38 @@ static int enable_msix(struct adapter *adapter)
 	 */
 	want = s->max_ethqsets + MSIX_EXTRAS;
 	need = adapter->params.nports + MSIX_EXTRAS;
-	while ((err = pci_enable_msix(adapter->pdev, entries, want)) >= need)
-		want = err;
 
-	if (err == 0) {
-		int nqsets = want - MSIX_EXTRAS;
-		if (nqsets < s->max_ethqsets) {
-			dev_warn(adapter->pdev_dev, "only enough MSI-X vectors"
-				 " for %d Queue Sets\n", nqsets);
-			s->max_ethqsets = nqsets;
-			if (nqsets < s->ethqsets)
-				reduce_ethqs(adapter, nqsets);
-		}
-		for (i = 0; i < want; ++i)
-			adapter->msix_info[i].vec = entries[i].vector;
-	} else if (err > 0) {
+	err = pci_msix_table_size(adapter->pdev);
+	if (err < 0)
+		return err;
+
+	want = min(want, err);
+	if (want < need) {
 		dev_info(adapter->pdev_dev, "only %d MSI-X vectors left,"
 			 " not using MSI-X\n", err);
-		err = -ENOSPC;
+		return -ENOSPC;
 	}
-	return err;
+
+	BUG_ON(want > ARRAY_SIZE(entries));
+	for (i = 0; i < want; ++i)
+		entries[i].entry = i;
+
+	err = pci_enable_msix(adapter->pdev, entries, want);
+	if (err)
+		return err;
+
+	nqsets = want - MSIX_EXTRAS;
+	if (nqsets < s->max_ethqsets) {
+		dev_warn(adapter->pdev_dev, "only enough MSI-X vectors"
+			 " for %d Queue Sets\n", nqsets);
+		s->max_ethqsets = nqsets;
+		if (nqsets < s->ethqsets)
+			reduce_ethqs(adapter, nqsets);
+	}
+	for (i = 0; i < want; ++i)
+		adapter->msix_info[i].vec = entries[i].vector;
+
+	return 0;
 }
 
 static const struct net_device_ops cxgb4vf_netdev_ops	= {
-- 
1.7.7.6

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