linux-kernel - [PATCH RFC 55/77] ntb: Update MSI/MSI-X interrupts enablement code

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Message-Id: <49eb592e15aaec804f9c11ca132d2b85c516aefa.1380703263.git.agordeev@redhat.com>
Date:	Wed,  2 Oct 2013 12:49:11 +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 55/77] ntb: 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/ntb/ntb_hw.c |   41 +++++++++++++----------------------------
 drivers/ntb/ntb_hw.h |    2 --
 2 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index eccd5e5..7776429 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -1032,23 +1032,26 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 	struct msix_entry *msix;
 	int msix_entries;
 	int rc, i;
-	u16 val;
 
-	if (!pdev->msix_cap) {
-		rc = -EIO;
+	rc = pci_msix_table_size(pdev);
+	if (rc < 0)
 		goto err;
-	}
 
-	rc = pci_read_config_word(pdev, pdev->msix_cap + PCI_MSIX_FLAGS, &val);
-	if (rc)
+	/*
+	 * On SNB, the link interrupt is always tied to 4th vector.  If
+	 * we can't get all 4, then we can't use MSI-X.
+	 */
+	if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
+		rc = -ENOSPC;
 		goto err;
-
-	msix_entries = msix_table_size(val);
-	if (msix_entries > ndev->limits.msix_cnt) {
+	}
+	if (rc > ndev->limits.msix_cnt) {
 		rc = -EINVAL;
 		goto err;
 	}
 
+	msix_entries = rc;
+
 	ndev->msix_entries = kmalloc(sizeof(struct msix_entry) * msix_entries,
 				     GFP_KERNEL);
 	if (!ndev->msix_entries) {
@@ -1060,26 +1063,8 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 		ndev->msix_entries[i].entry = i;
 
 	rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
-	if (rc < 0)
+	if (rc)
 		goto err1;
-	if (rc > 0) {
-		/* On SNB, the link interrupt is always tied to 4th vector.  If
-		 * we can't get all 4, then we can't use MSI-X.
-		 */
-		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
-			rc = -EIO;
-			goto err1;
-		}
-
-		dev_warn(&pdev->dev,
-			 "Only %d MSI-X vectors.  Limiting the number of queues to that number.\n",
-			 rc);
-		msix_entries = rc;
-
-		rc = pci_enable_msix(pdev, ndev->msix_entries, msix_entries);
-		if (rc)
-			goto err1;
-	}
 
 	for (i = 0; i < msix_entries; i++) {
 		msix = &ndev->msix_entries[i];
diff --git a/drivers/ntb/ntb_hw.h b/drivers/ntb/ntb_hw.h
index 0a31ced..50bd760 100644
--- a/drivers/ntb/ntb_hw.h
+++ b/drivers/ntb/ntb_hw.h
@@ -60,8 +60,6 @@
 #define PCI_DEVICE_ID_INTEL_NTB_SS_HSX		0x2F0F
 #define PCI_DEVICE_ID_INTEL_NTB_B2B_BWD		0x0C4E
 
-#define msix_table_size(control)	((control & PCI_MSIX_FLAGS_QSIZE)+1)
-
 #ifndef readq
 static inline u64 readq(void __iomem *addr)
 {
-- 
1.7.7.6

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