[Xen-devel] [PATCH 2/2] xen/pciback: use mutex rather than spinlock in vpci backend

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

Similar to the "xen/pciback: use mutex rather than spinlock in passthrough 
backend"
this patch converts the vpci backend to use a mutex instead of
a spinlock. Note that the code taking the lock won't ever get called
from non-sleepable context

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 drivers/xen/xen-pciback/vpci.c |   26 +++++++++++---------------
 1 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/xen/xen-pciback/vpci.c b/drivers/xen/xen-pciback/vpci.c
index a778552..01222d7 100644
--- a/drivers/xen/xen-pciback/vpci.c
+++ b/drivers/xen/xen-pciback/vpci.c
@@ -8,7 +8,7 @@
 #include <linux/list.h>
 #include <linux/slab.h>
 #include <linux/pci.h>
-#include <linux/spinlock.h>
+#include <linux/mutex.h>
 #include "pciback.h"
 
 #define PCI_SLOT_MAX 32
@@ -16,7 +16,7 @@
 struct vpci_dev_data {
        /* Access to dev_list must be protected by lock */
        struct list_head dev_list[PCI_SLOT_MAX];
-       spinlock_t lock;
+       struct mutex lock;
 };
 
 static inline struct list_head *list_first(struct list_head *head)
@@ -32,13 +32,12 @@ static struct pci_dev *__xen_pcibk_get_pci_dev(struct 
xen_pcibk_device *pdev,
        struct pci_dev_entry *entry;
        struct pci_dev *dev = NULL;
        struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
-       unsigned long flags;
 
        if (domain != 0 || bus != 0)
                return NULL;
 
        if (PCI_SLOT(devfn) < PCI_SLOT_MAX) {
-               spin_lock_irqsave(&vpci_dev->lock, flags);
+               mutex_lock(&vpci_dev->lock);
 
                list_for_each_entry(entry,
                                    &vpci_dev->dev_list[PCI_SLOT(devfn)],
@@ -49,7 +48,7 @@ static struct pci_dev *__xen_pcibk_get_pci_dev(struct 
xen_pcibk_device *pdev,
                        }
                }
 
-               spin_unlock_irqrestore(&vpci_dev->lock, flags);
+               mutex_unlock(&vpci_dev->lock);
        }
        return dev;
 }
@@ -70,7 +69,6 @@ static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device 
*pdev,
        int err = 0, slot, func = -1;
        struct pci_dev_entry *t, *dev_entry;
        struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
-       unsigned long flags;
 
        if ((dev->class >> 24) == PCI_BASE_CLASS_BRIDGE) {
                err = -EFAULT;
@@ -89,7 +87,7 @@ static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device 
*pdev,
 
        dev_entry->dev = dev;
 
-       spin_lock_irqsave(&vpci_dev->lock, flags);
+       mutex_lock(&vpci_dev->lock);
 
        /* Keep multi-function devices together on the virtual PCI bus */
        for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
@@ -128,7 +126,7 @@ static int __xen_pcibk_add_pci_dev(struct xen_pcibk_device 
*pdev,
                         "No more space on root virtual PCI bus");
 
 unlock:
-       spin_unlock_irqrestore(&vpci_dev->lock, flags);
+       mutex_unlock(&vpci_dev->lock);
 
        /* Publish this device. */
        if (!err)
@@ -144,9 +142,8 @@ static void __xen_pcibk_release_pci_dev(struct 
xen_pcibk_device *pdev,
        int slot;
        struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
        struct pci_dev *found_dev = NULL;
-       unsigned long flags;
 
-       spin_lock_irqsave(&vpci_dev->lock, flags);
+       mutex_lock(&vpci_dev->lock);
 
        for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
                struct pci_dev_entry *e;
@@ -162,7 +159,7 @@ static void __xen_pcibk_release_pci_dev(struct 
xen_pcibk_device *pdev,
        }
 
 out:
-       spin_unlock_irqrestore(&vpci_dev->lock, flags);
+       mutex_unlock(&vpci_dev->lock);
 
        if (found_dev)
                pcistub_put_pci_dev(found_dev);
@@ -177,7 +174,7 @@ static int __xen_pcibk_init_devices(struct xen_pcibk_device 
*pdev)
        if (!vpci_dev)
                return -ENOMEM;
 
-       spin_lock_init(&vpci_dev->lock);
+       mutex_init(&vpci_dev->lock);
 
        for (slot = 0; slot < PCI_SLOT_MAX; slot++)
                INIT_LIST_HEAD(&vpci_dev->dev_list[slot]);
@@ -221,10 +218,9 @@ static int __xen_pcibk_get_pcifront_dev(struct pci_dev 
*pcidev,
        struct pci_dev_entry *entry;
        struct pci_dev *dev = NULL;
        struct vpci_dev_data *vpci_dev = pdev->pci_dev_data;
-       unsigned long flags;
        int found = 0, slot;
 
-       spin_lock_irqsave(&vpci_dev->lock, flags);
+       mutex_lock(&vpci_dev->lock);
        for (slot = 0; slot < PCI_SLOT_MAX; slot++) {
                list_for_each_entry(entry,
                            &vpci_dev->dev_list[slot],
@@ -242,7 +238,7 @@ static int __xen_pcibk_get_pcifront_dev(struct pci_dev 
*pcidev,
                        }
                }
        }
-       spin_unlock_irqrestore(&vpci_dev->lock, flags);
+       mutex_lock(&vpci_dev->lock);
        return found;
 }
 
-- 
1.7.4.1


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel