netdev - [PATCH RFC 38/77] ixgbe: Update MSI/MSI-X interrupts enablement code

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Message-Id: <5b809a723104ca6350f4aefaae1ca2a44f7e7116.1380703263.git.agordeev@redhat.com>
Date:	Wed,  2 Oct 2013 12:48:54 +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 38/77] ixgbe: 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>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c |   62 +++++++++++++------------
 1 files changed, 32 insertions(+), 30 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index 90b4e10..2444a4d 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
@@ -711,37 +711,39 @@ static void ixgbe_acquire_msix_vectors(struct ixgbe_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) /* Success in acquiring all requested vectors. */
-			break;
-		else if (err < 0)
-			vectors = 0; /* Nasty failure, quit now */
-		else /* err == number of vectors we should try again with */
-			vectors = err;
-	}
+	err = pci_msix_table_size(adapter->pdev);
+	if (err < 0)
+		goto err_alloc_msix;
 
-	if (vectors < vector_threshold) {
-		/* Can't allocate enough MSI-X interrupts?  Oh well.
-		 * This just means we'll go with either a single MSI
-		 * vector or fall back to legacy interrupts.
-		 */
-		netif_printk(adapter, hw, KERN_DEBUG, adapter->netdev,
-			     "Unable to allocate MSI-X interrupts\n");
-		adapter->flags &= ~IXGBE_FLAG_MSIX_ENABLED;
-		kfree(adapter->msix_entries);
-		adapter->msix_entries = NULL;
-	} else {
-		adapter->flags |= IXGBE_FLAG_MSIX_ENABLED; /* Woot! */
-		/*
-		 * Adjust for only the vectors we'll use, which is minimum
-		 * of max_msix_q_vectors + NON_Q_VECTORS, or the number of
-		 * vectors we were allocated.
-		 */
-		vectors -= NON_Q_VECTORS;
-		adapter->num_q_vectors = min(vectors, adapter->max_q_vectors);
-	}
+	vectors = min(vectors, err);
+	if (vectors < vector_threshold)
+		goto err_alloc_msix;
+
+	err = pci_enable_msix(adapter->pdev, adapter->msix_entries, vectors);
+	if (err)
+		goto err_alloc_msix;
+
+	adapter->flags |= IXGBE_FLAG_MSIX_ENABLED; /* Woot! */
+	/*
+	 * Adjust for only the vectors we'll use, which is minimum
+	 * of max_msix_q_vectors + NON_Q_VECTORS, or the number of
+	 * vectors we were allocated.
+	 */
+	vectors -= NON_Q_VECTORS;
+	adapter->num_q_vectors = min(vectors, adapter->max_q_vectors);
+
+	return;
+
+err_alloc_msix:
+	/* Can't allocate enough MSI-X interrupts?  Oh well.
+	 * This just means we'll go with either a single MSI
+	 * vector or fall back to legacy interrupts.
+	 */
+	netif_printk(adapter, hw, KERN_DEBUG, adapter->netdev,
+		     "Unable to allocate MSI-X interrupts\n");
+	adapter->flags &= ~IXGBE_FLAG_MSIX_ENABLED;
+	kfree(adapter->msix_entries);
+	adapter->msix_entries = NULL;
 }
 
 static void ixgbe_add_ring(struct ixgbe_ring *ring,
-- 
1.7.7.6

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