[PATCH V2] pci: introduce static_nr to indicate domain_nr from which IDA

["Peng Fan (OSS)" <peng.fan@oss.nxp.com>]

From: Peng Fan <peng.fan@nxp.com>

When PCI node was created using an overlay and the overlay is
reverted/destroyed, the "linux,pci-domain" property no longer
exists, so of_get_pci_domain_nr will return failure. Then
of_pci_bus_release_domain_nr will actually use the dynamic IDA,
even if the IDA was allocated in static IDA.

Introduce a static_nr field in pci_bus to indicate whether the
IDA is a dynamic or static in order to free the correct one.

Fixes: c14f7ccc9f5d ("PCI: Assign PCI domain IDs by ida_alloc()")
Signed-off-by: Peng Fan <peng.fan@nxp.com>
---

V2:
 Update commit message
 Move static_nr:1 to stay besides others :1 fields.

 drivers/pci/pci.c   | 22 ++++++++++++++--------
 include/linux/pci.h |  1 +
 2 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 60230da957e0..5c98502bcda6 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -6881,10 +6881,10 @@ static void of_pci_reserve_static_domain_nr(void)
 	}
 }
 
-static int of_pci_bus_find_domain_nr(struct device *parent)
+static int of_pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent)
 {
 	static bool static_domains_reserved = false;
-	int domain_nr;
+	int domain_nr, ret;
 
 	/* On the first call scan device tree for static allocations. */
 	if (!static_domains_reserved) {
@@ -6892,6 +6892,8 @@ static int of_pci_bus_find_domain_nr(struct device *parent)
 		static_domains_reserved = true;
 	}
 
+	bus->static_nr = 0;
+
 	if (parent) {
 		/*
 		 * If domain is in DT, allocate it in static IDA.  This
@@ -6899,10 +6901,14 @@ static int of_pci_bus_find_domain_nr(struct device *parent)
 		 * in DT.
 		 */
 		domain_nr = of_get_pci_domain_nr(parent->of_node);
-		if (domain_nr >= 0)
-			return ida_alloc_range(&pci_domain_nr_static_ida,
-					       domain_nr, domain_nr,
-					       GFP_KERNEL);
+		if (domain_nr >= 0) {
+			ret = ida_alloc_range(&pci_domain_nr_static_ida,
+					      domain_nr, domain_nr, GFP_KERNEL);
+			if (ret >= 0)
+				bus->static_nr = 1;
+
+			return ret;
+		}
 	}
 
 	/*
@@ -6920,7 +6926,7 @@ static void of_pci_bus_release_domain_nr(struct pci_bus *bus, struct device *par
 		return;
 
 	/* Release domain from IDA where it was allocated. */
-	if (of_get_pci_domain_nr(parent->of_node) == bus->domain_nr)
+	if (bus->static_nr)
 		ida_free(&pci_domain_nr_static_ida, bus->domain_nr);
 	else
 		ida_free(&pci_domain_nr_dynamic_ida, bus->domain_nr);
@@ -6928,7 +6934,7 @@ static void of_pci_bus_release_domain_nr(struct pci_bus *bus, struct device *par
 
 int pci_bus_find_domain_nr(struct pci_bus *bus, struct device *parent)
 {
-	return acpi_disabled ? of_pci_bus_find_domain_nr(parent) :
+	return acpi_disabled ? of_pci_bus_find_domain_nr(bus, parent) :
 			       acpi_pci_bus_find_domain_nr(bus);
 }
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index eeb2e6f6130f..222a1729ea7e 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -677,6 +677,7 @@ struct pci_bus {
 	struct bin_attribute	*legacy_mem;	/* Legacy mem */
 	unsigned int		is_added:1;
 	unsigned int		unsafe_warn:1;	/* warned about RW1C config write */
+	unsigned int		static_nr:1;
 };
 
 #define to_pci_bus(n)	container_of(n, struct pci_bus, dev)
-- 
2.37.1