[PATCH] Added functionality that allows dynamically add and removedevice specific reset functions

[Tadeusz Struk]

I have a use case where I need to cleanup resource allocated for Virtual
Functions after a guest OS that used it crashed. This cleanup needs to
be done before the VF is being FLRed. The only possible way to do this
seems to be by using pci_dev_specific_reset() function. Unfortunately
this function only works for devices defined in a static table in the
drivers/pci/quirks.c file. This patch changes it so that specific reset
functions can be added and deleted dynamically.

Signed-off-by: Tadeusz Struk <tadeusz.struk@xxxxxxxxx>

---
 drivers/pci/pci.h    |   19 ++++++++++++++-
 drivers/pci/quirks.c |   63 ++++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 71 insertions(+), 11 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 1009a5e..10929d8 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -312,18 +312,35 @@ static inline resource_size_t pci_resource_alignment(struct pci_dev *dev,
 extern void pci_enable_acs(struct pci_dev *dev);
 
 struct pci_dev_reset_methods {
+	struct list_head list;
 	u16 vendor;
 	u16 device;
 	int (*reset)(struct pci_dev *dev, int probe);
 };
 
 #ifdef CONFIG_PCI_QUIRKS
-extern int pci_dev_specific_reset(struct pci_dev *dev, int probe);
+extern int
+pci_dev_specific_reset(struct pci_dev *dev, int probe);
+extern int
+pci_dev_specific_reset_add(const struct pci_dev_reset_methods *reset_method);
+extern int
+pci_dev_specific_reset_remove(const struct pci_dev_reset_methods *reset_method);
+
 #else
 static inline int pci_dev_specific_reset(struct pci_dev *dev, int probe)
 {
 	return -ENOTTY;
 }
+int
+pci_dev_specific_reset_add(const struct pci_dev_reset_methods *reset_method)
+{
+	return 0;
+}
+int
+pci_dev_specific_reset_remove(const struct pci_dev_reset_methods *reset_method)
+{
+	return 0;
+}
 #endif
 
 #endif /* DRIVERS_PCI_H */
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 6476547..963e527 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3070,26 +3070,69 @@ static int reset_intel_82599_sfp_virtfn(struct pci_dev *dev, int probe)
 }
 
 #define PCI_DEVICE_ID_INTEL_82599_SFP_VF   0x10ed
+static struct pci_dev_reset_methods intel_82599_sfp_vf_reset = {
+	.vendor = PCI_VENDOR_ID_INTEL,
+	.device = PCI_DEVICE_ID_INTEL_82599_SFP_VF,
+	.reset = reset_intel_82599_sfp_virtfn,
+	.list = LIST_HEAD_INIT(intel_82599_sfp_vf_reset.list)
+} ;
 
-static const struct pci_dev_reset_methods pci_dev_reset_methods[] = {
-	{ PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82599_SFP_VF,
-		 reset_intel_82599_sfp_virtfn },
-	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID,
-		reset_intel_generic_dev },
-	{ 0 }
-};
+static struct pci_dev_reset_methods intel_generic_reset = {
+	.vendor = PCI_VENDOR_ID_INTEL,
+	.device = PCI_ANY_ID,
+	.reset = reset_intel_generic_dev,
+	.list = LIST_HEAD_INIT(intel_generic_reset.list)
+} ;
+
+static DEFINE_SPINLOCK(reset_list_lock);
+static LIST_HEAD(reset_list);
+
+
+static int __init pci_dev_specific_reset_init(void)
+{
+	pci_dev_specific_reset_add(&intel_82599_sfp_vf_reset);
+	pci_dev_specific_reset_add(&intel_generic_reset);
+	return 0;
+}
+
+late_initcall(pci_dev_specific_reset_init);
+
+int
+pci_dev_specific_reset_add(const struct pci_dev_reset_methods *reset_method)
+{
+	if (reset_method && reset_method->reset) {
+		spin_lock(&reset_list_lock);
+		list_add((struct list_head *)&reset_method->list,
+			 &reset_list);
+		spin_unlock(&reset_list_lock);
+		return 0;
+	}
+	return -EINVAL;
+}
+EXPORT_SYMBOL(pci_dev_specific_reset_add);
+
+int
+pci_dev_specific_reset_remove(const struct pci_dev_reset_methods *reset_method)
+{
+	if (reset_method) {
+		spin_lock(&reset_list_lock);
+		list_del((struct list_head *)(&reset_method->list));
+		spin_unlock(&reset_list_lock);
+		return 0;
+	}
+	return -EINVAL;
+}
+EXPORT_SYMBOL(pci_dev_specific_reset_remove);
 
 int pci_dev_specific_reset(struct pci_dev *dev, int probe)
 {
 	const struct pci_dev_reset_methods *i;
-
-	for (i = pci_dev_reset_methods; i->reset; i++) {
+	list_for_each_entry(i, &reset_list, list) {
 		if ((i->vendor == dev->vendor ||
 		     i->vendor == (u16)PCI_ANY_ID) &&
 		    (i->device == dev->device ||
 		     i->device == (u16)PCI_ANY_ID))
 			return i->reset(dev, probe);
 	}
-
 	return -ENOTTY;
 }
-- 
1.7.7.6

--------------------------------------------------------------
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Registered Office: Collinstown Industrial Park, Leixlip, County Kildare
Registered Number: 308263
Business address: Dromore House, East Park, Shannon, Co. Clare

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