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-rw-r--r--kernel/resource.c68
1 files changed, 55 insertions, 13 deletions
diff --git a/kernel/resource.c b/kernel/resource.c
index 4aef8867fd4b..d7386986e10e 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -21,6 +21,7 @@
#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/pfn.h>
+#include <linux/mm.h>
#include <asm/io.h>
@@ -50,6 +51,14 @@ struct resource_constraint {
static DEFINE_RWLOCK(resource_lock);
+/*
+ * For memory hotplug, there is no way to free resource entries allocated
+ * by boot mem after the system is up. So for reusing the resource entry
+ * we need to remember the resource.
+ */
+static struct resource *bootmem_resource_free;
+static DEFINE_SPINLOCK(bootmem_resource_lock);
+
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
@@ -151,6 +160,40 @@ __initcall(ioresources_init);
#endif /* CONFIG_PROC_FS */
+static void free_resource(struct resource *res)
+{
+ if (!res)
+ return;
+
+ if (!PageSlab(virt_to_head_page(res))) {
+ spin_lock(&bootmem_resource_lock);
+ res->sibling = bootmem_resource_free;
+ bootmem_resource_free = res;
+ spin_unlock(&bootmem_resource_lock);
+ } else {
+ kfree(res);
+ }
+}
+
+static struct resource *alloc_resource(gfp_t flags)
+{
+ struct resource *res = NULL;
+
+ spin_lock(&bootmem_resource_lock);
+ if (bootmem_resource_free) {
+ res = bootmem_resource_free;
+ bootmem_resource_free = res->sibling;
+ }
+ spin_unlock(&bootmem_resource_lock);
+
+ if (res)
+ memset(res, 0, sizeof(struct resource));
+ else
+ res = kzalloc(sizeof(struct resource), flags);
+
+ return res;
+}
+
/* Return the conflict entry if you can't request it */
static struct resource * __request_resource(struct resource *root, struct resource *new)
{
@@ -771,7 +814,7 @@ static void __init __reserve_region_with_split(struct resource *root,
{
struct resource *parent = root;
struct resource *conflict;
- struct resource *res = kzalloc(sizeof(*res), GFP_ATOMIC);
+ struct resource *res = alloc_resource(GFP_ATOMIC);
struct resource *next_res = NULL;
if (!res)
@@ -796,7 +839,7 @@ static void __init __reserve_region_with_split(struct resource *root,
/* conflict covered whole area */
if (conflict->start <= res->start &&
conflict->end >= res->end) {
- kfree(res);
+ free_resource(res);
WARN_ON(next_res);
break;
}
@@ -806,10 +849,9 @@ static void __init __reserve_region_with_split(struct resource *root,
end = res->end;
res->end = conflict->start - 1;
if (conflict->end < end) {
- next_res = kzalloc(sizeof(*next_res),
- GFP_ATOMIC);
+ next_res = alloc_resource(GFP_ATOMIC);
if (!next_res) {
- kfree(res);
+ free_resource(res);
break;
}
next_res->name = name;
@@ -899,7 +941,7 @@ struct resource * __request_region(struct resource *parent,
const char *name, int flags)
{
DECLARE_WAITQUEUE(wait, current);
- struct resource *res = kzalloc(sizeof(*res), GFP_KERNEL);
+ struct resource *res = alloc_resource(GFP_KERNEL);
if (!res)
return NULL;
@@ -933,7 +975,7 @@ struct resource * __request_region(struct resource *parent,
continue;
}
/* Uhhuh, that didn't work out.. */
- kfree(res);
+ free_resource(res);
res = NULL;
break;
}
@@ -967,7 +1009,7 @@ int __check_region(struct resource *parent, resource_size_t start,
return -EBUSY;
release_resource(res);
- kfree(res);
+ free_resource(res);
return 0;
}
EXPORT_SYMBOL(__check_region);
@@ -1007,7 +1049,7 @@ void __release_region(struct resource *parent, resource_size_t start,
write_unlock(&resource_lock);
if (res->flags & IORESOURCE_MUXED)
wake_up(&muxed_resource_wait);
- kfree(res);
+ free_resource(res);
return;
}
p = &res->sibling;
@@ -1055,8 +1097,8 @@ int release_mem_region_adjustable(struct resource *parent,
if ((start < parent->start) || (end > parent->end))
return ret;
- /* The kzalloc() result gets checked later */
- new_res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+ /* The alloc_resource() result gets checked later */
+ new_res = alloc_resource(GFP_KERNEL);
p = &parent->child;
write_lock(&resource_lock);
@@ -1083,7 +1125,7 @@ int release_mem_region_adjustable(struct resource *parent,
if (res->start == start && res->end == end) {
/* free the whole entry */
*p = res->sibling;
- kfree(res);
+ free_resource(res);
ret = 0;
} else if (res->start == start && res->end != end) {
/* adjust the start */
@@ -1119,7 +1161,7 @@ int release_mem_region_adjustable(struct resource *parent,
}
write_unlock(&resource_lock);
- kfree(new_res);
+ free_resource(new_res);
return ret;
}
#endif /* CONFIG_MEMORY_HOTREMOVE */