[PATCH v2 08/24] PCI: Use pci_release_resource() instead of release_resource()

Ilpo Järvinen
2025-08-29T13:12:22Z

A few places in setup-bus.c call release_resource() directly and end up
duplicating functionality from pci_release_resource() such as parent check,
logging, and clearing the resource. Worse yet, the way the resource is
cleared is inconsistent between different sites.

Convert release_resource() calls into pci_release_resource() to remove code
duplication. This will also make the resource start, end, and flags
behavior consistent, i.e., start address is cleared, and only
IORESOURCE_UNSET is asserted for the resource.

While at it, eliminate the unnecessary initialization of idx variable in
pci_bridge_release_resources().

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/pci/setup-bus.c | 46 +++++++++++++----------------------------
drivers/pci/setup-res.c | 11 +++++++---
include/linux/pci.h | 2 +-
3 files changed, 23 insertions(+), 36 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 6bdc1af887da..b62465665abc 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -473,8 +473,6 @@ static void __assign_resources_sorted(struct list_head *head,
struct pci_dev_resource *dev_res, *tmp_res, *dev_res2;
struct resource *res;
struct pci_dev *dev;
- const char *res_name;
- int idx;
unsigned long fail_type;
resource_size_t add_align, align;

@@ -582,14 +580,7 @@ static void __assign_resources_sorted(struct list_head *head,
res = dev_res->res;
dev = dev_res->dev;

- if (!res->parent)
- continue;
-
- idx = pci_resource_num(dev, res);
- res_name = pci_resource_name(dev, idx);
- pci_dbg(dev, "%s %pR: releasing\n", res_name, res);
-
- release_resource(res);
+ pci_release_resource(dev, pci_resource_num(dev, res));
restore_dev_resource(dev_res);
}
/* Restore start/end/flags from saved list */
@@ -1732,7 +1723,7 @@ static void pci_bridge_release_resources(struct pci_bus *bus,
struct resource *r;
unsigned int old_flags;
struct resource *b_res;
- int idx = 1;
+ int idx, ret;

b_res = &dev->resource[PCI_BRIDGE_RESOURCES];

@@ -1766,21 +1757,18 @@ static void pci_bridge_release_resources(struct pci_bus *bus,

/* If there are children, release them all */
release_child_resources(r);
- if (!release_resource(r)) {
- type = old_flags = r->flags & PCI_RES_TYPE_MASK;
- pci_info(dev, "resource %d %pR released\n",
- PCI_BRIDGE_RESOURCES + idx, r);
- /* Keep the old size */
- resource_set_range(r, 0, resource_size(r));
- r->flags = 0;

- /* Avoiding touch the one without PREF */
- if (type & IORESOURCE_PREFETCH)
- type = IORESOURCE_PREFETCH;
- __pci_setup_bridge(bus, type);
- /* For next child res under same bridge */
- r->flags = old_flags;
- }
+ type = old_flags = r->flags & PCI_RES_TYPE_MASK;
+ ret = pci_release_resource(dev, PCI_BRIDGE_RESOURCES + idx);
+ if (ret)
+ return;
+
+ /* Avoiding touch the one without PREF */
+ if (type & IORESOURCE_PREFETCH)
+ type = IORESOURCE_PREFETCH;
+ __pci_setup_bridge(bus, type);
+ /* For next child res under same bridge */
+ r->flags = old_flags;
}

enum release_type {
@@ -2425,7 +2413,6 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
for (i = PCI_BRIDGE_RESOURCES; i < PCI_BRIDGE_RESOURCE_END;
i++) {
struct resource *res = &bridge->resource[i];
- const char *res_name = pci_resource_name(bridge, i);

if ((res->flags ^ type) & PCI_RES_TYPE_MASK)
continue;
@@ -2438,12 +2425,7 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type)
if (ret)
goto cleanup;

- pci_info(bridge, "%s %pR: releasing\n", res_name, res);
-
- if (res->parent)
- release_resource(res);
- res->start = 0;
- res->end = 0;
+ pci_release_resource(bridge, i);
break;
}
if (i == PCI_BRIDGE_RESOURCE_END)
diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index d2b3ed51e880..0468c058b598 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -406,20 +406,25 @@ int pci_reassign_resource(struct pci_dev *dev, int resno,
return 0;
}

-void pci_release_resource(struct pci_dev *dev, int resno)
+int pci_release_resource(struct pci_dev *dev, int resno)
{
struct resource *res = pci_resource_n(dev, resno);
const char *res_name = pci_resource_name(dev, resno);
+ int ret;

if (!res->parent)
- return;
+ return 0;

pci_info(dev, "%s %pR: releasing\n", res_name, res);

- release_resource(res);
+ ret = release_resource(res);
+ if (ret)
+ return ret;
res->end = resource_size(res) - 1;
res->start = 0;
res->flags |= IORESOURCE_UNSET;
+
+ return 0;
}
EXPORT_SYMBOL(pci_release_resource);

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 59876de13860..275df4058767 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1417,7 +1417,7 @@ void pci_reset_secondary_bus(struct pci_dev *dev);
void pcibios_reset_secondary_bus(struct pci_dev *dev);
void pci_update_resource(struct pci_dev *dev, int resno);
int __must_check pci_assign_resource(struct pci_dev *dev, int i);
-void pci_release_resource(struct pci_dev *dev, int resno);
+int pci_release_resource(struct pci_dev *dev, int resno);
static inline int pci_rebar_bytes_to_size(u64 bytes)
{
bytes = roundup_pow_of_two(bytes);
--
2.39.5