* Arbitrary resource management.
*/
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/init.h>
};
EXPORT_SYMBOL(iomem_resource);
+/* constraints to be met while allocating resources */
+struct resource_constraint {
+ resource_size_t min, max, align;
+ resource_size_t (*alignf)(void *, const struct resource *,
+ resource_size_t, resource_size_t);
+ void *alignf_data;
+};
+
static DEFINE_RWLOCK(resource_lock);
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
}
+void __weak arch_remove_reservations(struct resource *avail)
+{
+}
+
+static resource_size_t simple_align_resource(void *data,
+ const struct resource *avail,
+ resource_size_t size,
+ resource_size_t align)
+{
+ return avail->start;
+}
+
+static void resource_clip(struct resource *res, resource_size_t min,
+ resource_size_t max)
+{
+ if (res->start < min)
+ res->start = min;
+ if (res->end > max)
+ res->end = max;
+}
+
+static bool resource_contains(struct resource *res1, struct resource *res2)
+{
+ return res1->start <= res2->start && res1->end >= res2->end;
+}
+
/*
- * Find empty slot in the resource tree given range and alignment.
+ * Find empty slot in the resource tree with the given range and
+ * alignment constraints
*/
-static int find_resource(struct resource *root, struct resource *new,
- resource_size_t size, resource_size_t min,
- resource_size_t max, resource_size_t align,
- resource_size_t (*alignf)(void *,
- const struct resource *,
- resource_size_t,
- resource_size_t),
- void *alignf_data)
+static int __find_resource(struct resource *root, struct resource *old,
+ struct resource *new,
+ resource_size_t size,
+ struct resource_constraint *constraint)
{
struct resource *this = root->child;
- struct resource tmp = *new;
+ struct resource tmp = *new, avail, alloc;
+ tmp.flags = new->flags;
tmp.start = root->start;
/*
* Skip past an allocated resource that starts at 0, since the assignment
* of this->start - 1 to tmp->end below would cause an underflow.
*/
- if (this && this->start == 0) {
- tmp.start = this->end + 1;
+ if (this && this->start == root->start) {
+ tmp.start = (this == old) ? old->start : this->end + 1;
this = this->sibling;
}
for(;;) {
if (this)
- tmp.end = this->start - 1;
+ tmp.end = (this == old) ? this->end : this->start - 1;
else
tmp.end = root->end;
- if (tmp.start < min)
- tmp.start = min;
- if (tmp.end > max)
- tmp.end = max;
- tmp.start = ALIGN(tmp.start, align);
- if (alignf)
- tmp.start = alignf(alignf_data, &tmp, size, align);
- if (tmp.start < tmp.end && tmp.end - tmp.start >= size - 1) {
- new->start = tmp.start;
- new->end = tmp.start + size - 1;
- return 0;
+
+ if (tmp.end < tmp.start)
+ goto next;
+
+ resource_clip(&tmp, constraint->min, constraint->max);
+ arch_remove_reservations(&tmp);
+
+ /* Check for overflow after ALIGN() */
+ avail = *new;
+ avail.start = ALIGN(tmp.start, constraint->align);
+ avail.end = tmp.end;
+ if (avail.start >= tmp.start) {
+ alloc.start = constraint->alignf(constraint->alignf_data, &avail,
+ size, constraint->align);
+ alloc.end = alloc.start + size - 1;
+ if (resource_contains(&avail, &alloc)) {
+ new->start = alloc.start;
+ new->end = alloc.end;
+ return 0;
+ }
}
- if (!this)
+
+next: if (!this || this->end == root->end)
break;
- tmp.start = this->end + 1;
+
+ if (this != old)
+ tmp.start = this->end + 1;
this = this->sibling;
}
return -EBUSY;
}
+/*
+ * Find empty slot in the resource tree given range and alignment.
+ */
+static int find_resource(struct resource *root, struct resource *new,
+ resource_size_t size,
+ struct resource_constraint *constraint)
+{
+ return __find_resource(root, NULL, new, size, constraint);
+}
+
+/**
+ * reallocate_resource - allocate a slot in the resource tree given range & alignment.
+ * The resource will be relocated if the new size cannot be reallocated in the
+ * current location.
+ *
+ * @root: root resource descriptor
+ * @old: resource descriptor desired by caller
+ * @newsize: new size of the resource descriptor
+ * @constraint: the size and alignment constraints to be met.
+ */
+int reallocate_resource(struct resource *root, struct resource *old,
+ resource_size_t newsize,
+ struct resource_constraint *constraint)
+{
+ int err=0;
+ struct resource new = *old;
+ struct resource *conflict;
+
+ write_lock(&resource_lock);
+
+ if ((err = __find_resource(root, old, &new, newsize, constraint)))
+ goto out;
+
+ if (resource_contains(&new, old)) {
+ old->start = new.start;
+ old->end = new.end;
+ goto out;
+ }
+
+ if (old->child) {
+ err = -EBUSY;
+ goto out;
+ }
+
+ if (resource_contains(old, &new)) {
+ old->start = new.start;
+ old->end = new.end;
+ } else {
+ __release_resource(old);
+ *old = new;
+ conflict = __request_resource(root, old);
+ BUG_ON(conflict);
+ }
+out:
+ write_unlock(&resource_lock);
+ return err;
+}
+
+
/**
- * allocate_resource - allocate empty slot in the resource tree given range & alignment
+ * allocate_resource - allocate empty slot in the resource tree given range & alignment.
+ * The resource will be reallocated with a new size if it was already allocated
* @root: root resource descriptor
* @new: resource descriptor desired by caller
* @size: requested resource region size
void *alignf_data)
{
int err;
+ struct resource_constraint constraint;
+
+ if (!alignf)
+ alignf = simple_align_resource;
+
+ constraint.min = min;
+ constraint.max = max;
+ constraint.align = align;
+ constraint.alignf = alignf;
+ constraint.alignf_data = alignf_data;
+
+ if ( new->parent ) {
+ /* resource is already allocated, try reallocating with
+ the new constraints */
+ return reallocate_resource(root, new, size, &constraint);
+ }
write_lock(&resource_lock);
- err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
+ err = find_resource(root, new, size, &constraint);
if (err >= 0 && __request_resource(root, new))
err = -EBUSY;
write_unlock(&resource_lock);
EXPORT_SYMBOL(allocate_resource);
+/**
+ * lookup_resource - find an existing resource by a resource start address
+ * @root: root resource descriptor
+ * @start: resource start address
+ *
+ * Returns a pointer to the resource if found, NULL otherwise
+ */
+struct resource *lookup_resource(struct resource *root, resource_size_t start)
+{
+ struct resource *res;
+
+ read_lock(&resource_lock);
+ for (res = root->child; res; res = res->sibling) {
+ if (res->start == start)
+ break;
+ }
+ read_unlock(&resource_lock);
+
+ return res;
+}
+
/*
* Insert a resource into the resource tree. If successful, return NULL,
* otherwise return the conflicting resource (compare to __request_resource())
write_unlock(&resource_lock);
return result;
}
+EXPORT_SYMBOL(adjust_resource);
static void __init __reserve_region_with_split(struct resource *root,
resource_size_t start, resource_size_t end,
write_unlock(&resource_lock);
}
-EXPORT_SYMBOL(adjust_resource);
-
/**
* resource_alignment - calculate resource's alignment
* @res: resource pointer
projects / linux-flexiantxendom0-3.2.10.git / blobdiff