#include <linux/seq_file.h>
#include <linux/device.h>
#include <linux/pfn.h>
+#include <linux/mm.h>
#include <asm/io.h>
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;
#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)
{
write_unlock(&resource_lock);
}
-/**
- * adjust_resource - modify a resource's start and size
- * @res: resource to modify
- * @start: new start value
- * @size: new size
- *
- * Given an existing resource, change its start and size to match the
- * arguments. Returns 0 on success, -EBUSY if it can't fit.
- * Existing children of the resource are assumed to be immutable.
- */
-int adjust_resource(struct resource *res, resource_size_t start, resource_size_t size)
+static int __adjust_resource(struct resource *res, resource_size_t start,
+ resource_size_t size)
{
struct resource *tmp, *parent = res->parent;
resource_size_t end = start + size - 1;
int result = -EBUSY;
- write_lock(&resource_lock);
-
if (!parent)
goto skip;
result = 0;
out:
+ return result;
+}
+
+/**
+ * adjust_resource - modify a resource's start and size
+ * @res: resource to modify
+ * @start: new start value
+ * @size: new size
+ *
+ * Given an existing resource, change its start and size to match the
+ * arguments. Returns 0 on success, -EBUSY if it can't fit.
+ * Existing children of the resource are assumed to be immutable.
+ */
+int adjust_resource(struct resource *res, resource_size_t start,
+ resource_size_t size)
+{
+ int result;
+
+ write_lock(&resource_lock);
+ result = __adjust_resource(res, start, size);
write_unlock(&resource_lock);
return result;
}
{
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)
/* conflict covered whole area */
if (conflict->start <= res->start &&
conflict->end >= res->end) {
- kfree(res);
+ free_resource(res);
WARN_ON(next_res);
break;
}
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;
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;
continue;
}
/* Uhhuh, that didn't work out.. */
- kfree(res);
+ free_resource(res);
res = NULL;
break;
}
return -EBUSY;
release_resource(res);
- kfree(res);
+ free_resource(res);
return 0;
}
EXPORT_SYMBOL(__check_region);
write_unlock(&resource_lock);
if (res->flags & IORESOURCE_MUXED)
wake_up(&muxed_resource_wait);
- kfree(res);
+ free_resource(res);
return;
}
p = &res->sibling;
}
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 alloc_resource() result gets checked later */
+ new_res = alloc_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;
+ free_resource(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);
+ free_resource(new_res);
+ return ret;
+}
+#endif /* CONFIG_MEMORY_HOTREMOVE */
+
/*
* Managed region resource
*/
projects / karo-tx-linux.git / blobdiff