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Commit 74d33ded authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
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xen/pciback: use mutex rather than spinlock in vpci backend 



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: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent b1766b62

drivers/xen/xen-pciback/vpci.c

+11 −15
Original line number Diff line number Diff line
@@ -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;

}