static DEFINE_RWLOCK(resource_lock);
+/*
+ * By default, we allocate free space bottom-up. The architecture can request
+ * top-down by clearing this flag. The user can override the architecture's
+ * choice with the "resource_alloc_from_bottom" kernel boot option, but that
+ * should only be a debugging tool.
+ */
+int resource_alloc_from_bottom = 1;
+
+static __init int setup_alloc_from_bottom(char *s)
+{
+ printk(KERN_INFO
+ "resource: allocating from bottom-up; please report a bug\n");
+ resource_alloc_from_bottom = 1;
+ return 0;
+}
+early_param("resource_alloc_from_bottom", setup_alloc_from_bottom);
+
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
struct resource *p = v;
return walk_system_ram_range(pfn, 1, NULL, __is_ram) == 1;
}
+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 the resource before "child" in the sibling list of "root" children.
+ */
+static struct resource *find_sibling_prev(struct resource *root, struct resource *child)
+{
+ struct resource *this;
+
+ for (this = root->child; this; this = this->sibling)
+ if (this->sibling == child)
+ return this;
+
+ return NULL;
+}
+
/*
* Find empty slot in the resource tree given range and alignment.
+ * This version allocates from the end of the root resource first.
+ */
+static int find_resource_from_top(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)
+{
+ struct resource *this;
+ struct resource tmp, avail, alloc;
+
+ tmp.start = root->end;
+ tmp.end = root->end;
+
+ this = find_sibling_prev(root, NULL);
+ for (;;) {
+ if (this) {
+ if (this->end < root->end)
+ tmp.start = this->end + 1;
+ } else
+ tmp.start = root->start;
+
+ resource_clip(&tmp, min, max);
+
+ /* Check for overflow after ALIGN() */
+ avail = *new;
+ avail.start = ALIGN(tmp.start, align);
+ avail.end = tmp.end;
+ if (avail.start >= tmp.start) {
+ alloc.start = alignf(alignf_data, &avail, size, align);
+ alloc.end = alloc.start + size - 1;
+ if (resource_contains(&avail, &alloc)) {
+ new->start = alloc.start;
+ new->end = alloc.end;
+ return 0;
+ }
+ }
+
+ if (!this || this->start == root->start)
+ break;
+
+ tmp.end = this->start - 1;
+ this = find_sibling_prev(root, this);
+ }
+ return -EBUSY;
+}
+
+/*
+ * Find empty slot in the resource tree given range and alignment.
+ * This version allocates from the beginning of the root resource first.
*/
static int find_resource(struct resource *root, struct resource *new,
resource_size_t size, resource_size_t min,
void *alignf_data)
{
struct resource *this = root->child;
- struct resource tmp = *new;
+ struct resource tmp = *new, avail, alloc;
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.
+ * 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;
this = this->sibling;
}
- for(;;) {
+ for (;;) {
if (this)
tmp.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;
+
+ resource_clip(&tmp, min, max);
+
+ /* Check for overflow after ALIGN() */
+ avail = *new;
+ avail.start = ALIGN(tmp.start, align);
+ avail.end = tmp.end;
+ if (avail.start >= tmp.start) {
+ alloc.start = alignf(alignf_data, &avail, size, align);
+ alloc.end = alloc.start + size - 1;
+ if (resource_contains(&avail, &alloc)) {
+ new->start = alloc.start;
+ new->end = alloc.end;
+ return 0;
+ }
}
+
if (!this)
break;
+
tmp.start = this->end + 1;
this = this->sibling;
}
{
int err;
+ if (!alignf)
+ alignf = simple_align_resource;
+
write_lock(&resource_lock);
- err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
+ if (resource_alloc_from_bottom)
+ err = find_resource(root, new, size, min, max, align, alignf, alignf_data);
+ else
+ err = find_resource_from_top(root, new, size, min, max, align, alignf, alignf_data);
if (err >= 0 && __request_resource(root, new))
err = -EBUSY;
write_unlock(&resource_lock);
git.openpandora.org / pandora-kernel.git / blobdiff