[PATCH v2 45/49] PCI: Don't release fixed resource for realloc

Yinghai Lu
2015-07-14T22:53:13Z

We should not release bridge resource if there is fixed resources
under it, otherwise the children firmware would stop working.

Reported-by: Paul Johnson <pjay@nwtrail.com>
Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=92351
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: stable@vger.kernel.org
---
drivers/pci/setup-bus.c | 6 ++++--
include/linux/ioport.h | 2 +-
kernel/resource.c | 28 ++++++++++++++++++++++++++--
3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index dc9ba41..9d5423c 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -2059,14 +2059,16 @@ static void pci_bridge_release_resources(struct pci_bus *bus,

r = &b_res[idx];

- if (!r->parent)
+ if (!r->parent || r->flags & IORESOURCE_PCI_FIXED)
return;

/*
* if there are children under that, we should release them
* all
*/
- release_child_resources(r);
+ if (!release_child_resources(r))
+ return;
+
if (!release_resource(r)) {
type = old_flags = r->flags & type_mask;
dev_printk(KERN_DEBUG, &dev->dev, "resource %d %pR released\n",
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 388e3ae..27dbb18 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -141,7 +141,7 @@ extern struct resource iomem_resource;
extern struct resource *request_resource_conflict(struct resource *root, struct resource *new);
extern int request_resource(struct resource *root, struct resource *new);
extern int release_resource(struct resource *new);
-void release_child_resources(struct resource *new);
+bool release_child_resources(struct resource *new);
extern void reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
const char *name);
diff --git a/kernel/resource.c b/kernel/resource.c
index c630ef1..0285f11 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -276,11 +276,35 @@ static void __release_child_resources(struct resource *r)
}
}

-void release_child_resources(struct resource *r)
+static bool __has_fixed_child_resources(struct resource *r)
{
+ struct resource *p;
+
+ p = r->child;
+ while (p) {
+ if (p->flags & IORESOURCE_PCI_FIXED)
+ return true;
+
+ if (__has_fixed_child_resources(p))
+ return true;
+
+ p = p->sibling;
+ }
+
+ return false;
+}
+
+bool release_child_resources(struct resource *r)
+{
+ bool fixed;
+
write_lock(&resource_lock);
- __release_child_resources(r);
+ fixed = __has_fixed_child_resources(r);
+ if (!fixed)
+ __release_child_resources(r);
write_unlock(&resource_lock);
+
+ return !fixed;
}

/**
--
1.8.4.5