IO resources: add reserve_region_with_split()
add reserve_region_with_split() to not lose e820 reserved entries if
they overlap with existing IO regions:
with test case by extend 0xe0000000 - 0xeffffff to 0xdd800000 -
we get:
e0000000-efffffff : PCI MMCONFIG 0
e0000000-efffffff : reserved
and in /proc/iomem we get:
found conflict for reserved [dd800000, efffffff], try to reserve with split
__reserve_region_with_split: (PCI Bus #80) [dd000000, ddffffff], res: (reserved) [dd800000, efffffff]
__reserve_region_with_split: (PCI Bus #00) [de000000, dfffffff], res: (reserved) [de000000, efffffff]
initcall pci_subsys_init+0x0/0x121 returned 0 after 381 msecs
in dmesg
various fixes and improvements suggested by Linus.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/resource.c b/kernel/resource.c
index 03d796c..414d6fc 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -516,6 +516,74 @@
return result;
}
+static void __init __reserve_region_with_split(struct resource *root,
+ resource_size_t start, resource_size_t end,
+ const char *name)
+{
+ struct resource *parent = root;
+ struct resource *conflict;
+ struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
+
+ if (!res)
+ return;
+
+ res->name = name;
+ res->start = start;
+ res->end = end;
+ res->flags = IORESOURCE_BUSY;
+
+ for (;;) {
+ conflict = __request_resource(parent, res);
+ if (!conflict)
+ break;
+ if (conflict != parent) {
+ parent = conflict;
+ if (!(conflict->flags & IORESOURCE_BUSY))
+ continue;
+ }
+
+ /* Uhhuh, that didn't work out.. */
+ kfree(res);
+ res = NULL;
+ break;
+ }
+
+ if (!res) {
+ printk(KERN_DEBUG " __reserve_region_with_split: (%s) [%llx, %llx], res: (%s) [%llx, %llx]\n",
+ conflict->name, conflict->start, conflict->end,
+ name, start, end);
+
+ /* failed, split and try again */
+
+ /* conflict coverred whole area */
+ if (conflict->start <= start && conflict->end >= end)
+ return;
+
+ if (conflict->start > start)
+ __reserve_region_with_split(root, start, conflict->start-1, name);
+ if (!(conflict->flags & IORESOURCE_BUSY)) {
+ resource_size_t common_start, common_end;
+
+ common_start = max(conflict->start, start);
+ common_end = min(conflict->end, end);
+ if (common_start < common_end)
+ __reserve_region_with_split(root, common_start, common_end, name);
+ }
+ if (conflict->end < end)
+ __reserve_region_with_split(root, conflict->end+1, end, name);
+ }
+
+}
+
+void reserve_region_with_split(struct resource *root,
+ resource_size_t start, resource_size_t end,
+ const char *name)
+{
+ write_lock(&resource_lock);
+ __reserve_region_with_split(root, start, end, name);
+ write_unlock(&resource_lock);
+}
+
EXPORT_SYMBOL(adjust_resource);
/**
