linux-kernel - [PATCH v3 1/3] xen/pciback: simplify pcistub device handling

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Date:   Thu, 22 Sep 2016 10:45:39 +0200
From:   Juergen Gross <jgross@...e.com>
To:     linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Cc:     boris.ostrovsky@...cle.com, david.vrabel@...rix.com,
        Juergen Gross <jgross@...e.com>
Subject: [PATCH v3 1/3] xen/pciback: simplify pcistub device handling

The Xen pciback driver maintains a list of all its seized devices.
There are two functions searching the list for a specific device with
basically the same semantics just returning different structures in
case of a match.

Split out the search function.

Signed-off-by: Juergen Gross <jgross@...e.com>
---
 drivers/xen/xen-pciback/pci_stub.c | 50 +++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c
index 258b7c3..79a9e4d 100644
--- a/drivers/xen/xen-pciback/pci_stub.c
+++ b/drivers/xen/xen-pciback/pci_stub.c
@@ -149,29 +149,36 @@ static inline void pcistub_device_put(struct pcistub_device *psdev)
 	kref_put(&psdev->kref, pcistub_device_release);
 }
 
+static struct pcistub_device *pcistub_device_find_locked(int domain, int bus,
+							 int slot, int func)
+{
+	struct pcistub_device *psdev;
+
+	list_for_each_entry(psdev, &pcistub_devices, dev_list) {
+		if (psdev->dev != NULL
+		    && domain == pci_domain_nr(psdev->dev->bus)
+		    && bus == psdev->dev->bus->number
+		    && slot == PCI_SLOT(psdev->dev->devfn)
+		    && func == PCI_FUNC(psdev->dev->devfn)) {
+			return psdev;
+		}
+	}
+
+	return NULL;
+}
+
 static struct pcistub_device *pcistub_device_find(int domain, int bus,
 						  int slot, int func)
 {
-	struct pcistub_device *psdev = NULL;
+	struct pcistub_device *psdev;
 	unsigned long flags;
 
 	spin_lock_irqsave(&pcistub_devices_lock, flags);
 
-	list_for_each_entry(psdev, &pcistub_devices, dev_list) {
-		if (psdev->dev != NULL
-		    && domain == pci_domain_nr(psdev->dev->bus)
-		    && bus == psdev->dev->bus->number
-		    && slot == PCI_SLOT(psdev->dev->devfn)
-		    && func == PCI_FUNC(psdev->dev->devfn)) {
-			pcistub_device_get(psdev);
-			goto out;
-		}
-	}
+	psdev = pcistub_device_find_locked(domain, bus, slot, func);
+	if (psdev)
+		pcistub_device_get(psdev);
 
-	/* didn't find it */
-	psdev = NULL;
-
-out:
 	spin_unlock_irqrestore(&pcistub_devices_lock, flags);
 	return psdev;
 }
@@ -207,16 +214,9 @@ struct pci_dev *pcistub_get_pci_dev_by_slot(struct xen_pcibk_device *pdev,
 
 	spin_lock_irqsave(&pcistub_devices_lock, flags);
 
-	list_for_each_entry(psdev, &pcistub_devices, dev_list) {
-		if (psdev->dev != NULL
-		    && domain == pci_domain_nr(psdev->dev->bus)
-		    && bus == psdev->dev->bus->number
-		    && slot == PCI_SLOT(psdev->dev->devfn)
-		    && func == PCI_FUNC(psdev->dev->devfn)) {
-			found_dev = pcistub_device_get_pci_dev(pdev, psdev);
-			break;
-		}
-	}
+	psdev = pcistub_device_find_locked(domain, bus, slot, func);
+	if (psdev)
+		found_dev = pcistub_device_get_pci_dev(pdev, psdev);
 
 	spin_unlock_irqrestore(&pcistub_devices_lock, flags);
 	return found_dev;
-- 
2.6.6