From 1317529c9c19485b3aa0db74e689f98985fb35e9 Mon Sep 17 00:00:00 2001
From: Toshi Kani <toshi.kani@hp.com>
Date: Mon, 29 Apr 2013 15:08:19 -0700
Subject: [PATCH] --- yaml --- r: 365439 b: refs/heads/master c:
 825f787bb49676083b97c1de1f8f2f8f26b5c908 h: refs/heads/master i:   365437:
 1af4f4ed324564498b40a2a678079a8bef310411   365435:
 ef290d1c26cb997b00359d741c8b98d4630a7403   365431:
 868bd4aaa65c76ddf6265fc5faa2c9b871360809   365423:
 28ed10583428850494090144ea17a74186e930c0   365407:
 a7bd890e666c93d68652f69a5dd2232493c75cc7   365375:
 bea7671e0bdef63c28ca4687043d670e224733ec   365311:
 6535af670fc31a4200fdb19a4b6194cec0a75dc1 v: v3

---
 [refs]                       |   2 +-
 trunk/include/linux/ioport.h |   4 ++
 trunk/kernel/resource.c      | 103 +++++++++++++++++++++++++++++++++++
 3 files changed, 108 insertions(+), 1 deletion(-)

diff --git a/[refs] b/[refs]
index d30b49caad03..fd3e6674c52b 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ae8e3a915aef5af5ace5936c56f05f0b1502ded1
+refs/heads/master: 825f787bb49676083b97c1de1f8f2f8f26b5c908
diff --git a/trunk/include/linux/ioport.h b/trunk/include/linux/ioport.h
index 85ac9b9b72a2..89b7c24a36e9 100644
--- a/trunk/include/linux/ioport.h
+++ b/trunk/include/linux/ioport.h
@@ -192,6 +192,10 @@ extern struct resource * __request_region(struct resource *,
 extern int __check_region(struct resource *, resource_size_t, resource_size_t);
 extern void __release_region(struct resource *, resource_size_t,
 				resource_size_t);
+#ifdef CONFIG_MEMORY_HOTREMOVE
+extern int release_mem_region_adjustable(struct resource *, resource_size_t,
+				resource_size_t);
+#endif
 
 static inline int __deprecated check_region(resource_size_t s,
 						resource_size_t n)
diff --git a/trunk/kernel/resource.c b/trunk/kernel/resource.c
index ae246f97c5d3..4aef8867fd4b 100644
--- a/trunk/kernel/resource.c
+++ b/trunk/kernel/resource.c
@@ -1021,6 +1021,109 @@ void __release_region(struct resource *parent, resource_size_t start,
 }
 EXPORT_SYMBOL(__release_region);
 
+#ifdef CONFIG_MEMORY_HOTREMOVE
+/**
+ * release_mem_region_adjustable - release a previously reserved memory region
+ * @parent: parent resource descriptor
+ * @start: resource start address
+ * @size: resource region size
+ *
+ * This interface is intended for memory hot-delete.  The requested region
+ * is released from a currently busy memory resource.  The requested region
+ * must either match exactly or fit into a single busy resource entry.  In
+ * the latter case, the remaining resource is adjusted accordingly.
+ * Existing children of the busy memory resource must be immutable in the
+ * request.
+ *
+ * Note:
+ * - Additional release conditions, such as overlapping region, can be
+ *   supported after they are confirmed as valid cases.
+ * - When a busy memory resource gets split into two entries, the code
+ *   assumes that all children remain in the lower address entry for
+ *   simplicity.  Enhance this logic when necessary.
+ */
+int release_mem_region_adjustable(struct resource *parent,
+			resource_size_t start, resource_size_t size)
+{
+	struct resource **p;
+	struct resource *res;
+	struct resource *new_res;
+	resource_size_t end;
+	int ret = -EINVAL;
+
+	end = start + size - 1;
+	if ((start < parent->start) || (end > parent->end))
+		return ret;
+
+	/* The kzalloc() result gets checked later */
+	new_res = kzalloc(sizeof(struct resource), GFP_KERNEL);
+
+	p = &parent->child;
+	write_lock(&resource_lock);
+
+	while ((res = *p)) {
+		if (res->start >= end)
+			break;
+
+		/* look for the next resource if it does not fit into */
+		if (res->start > start || res->end < end) {
+			p = &res->sibling;
+			continue;
+		}
+
+		if (!(res->flags & IORESOURCE_MEM))
+			break;
+
+		if (!(res->flags & IORESOURCE_BUSY)) {
+			p = &res->child;
+			continue;
+		}
+
+		/* found the target resource; let's adjust accordingly */
+		if (res->start == start && res->end == end) {
+			/* free the whole entry */
+			*p = res->sibling;
+			kfree(res);
+			ret = 0;
+		} else if (res->start == start && res->end != end) {
+			/* adjust the start */
+			ret = __adjust_resource(res, end + 1,
+						res->end - end);
+		} else if (res->start != start && res->end == end) {
+			/* adjust the end */
+			ret = __adjust_resource(res, res->start,
+						start - res->start);
+		} else {
+			/* split into two entries */
+			if (!new_res) {
+				ret = -ENOMEM;
+				break;
+			}
+			new_res->name = res->name;
+			new_res->start = end + 1;
+			new_res->end = res->end;
+			new_res->flags = res->flags;
+			new_res->parent = res->parent;
+			new_res->sibling = res->sibling;
+			new_res->child = NULL;
+
+			ret = __adjust_resource(res, res->start,
+						start - res->start);
+			if (ret)
+				break;
+			res->sibling = new_res;
+			new_res = NULL;
+		}
+
+		break;
+	}
+
+	write_unlock(&resource_lock);
+	kfree(new_res);
+	return ret;
+}
+#endif	/* CONFIG_MEMORY_HOTREMOVE */
+
 /*
  * Managed region resource
  */