Resource handling: add 'insert_resource_expand_to_fit()' function
Not used anywhere yet, but this complements the existing plain 'insert_resource()' functionality with a version that can expand the resource we are adding in order to fix up any conflicts it has with existing resources. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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00aeb429a0
Коммит
bef69ea0dc
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@ -109,6 +109,7 @@ extern struct resource iomem_resource;
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extern int request_resource(struct resource *root, struct resource *new);
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extern int release_resource(struct resource *new);
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extern int insert_resource(struct resource *parent, struct resource *new);
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extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new);
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extern int allocate_resource(struct resource *root, struct resource *new,
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resource_size_t size, resource_size_t min,
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resource_size_t max, resource_size_t align,
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@ -362,35 +362,21 @@ int allocate_resource(struct resource *root, struct resource *new,
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EXPORT_SYMBOL(allocate_resource);
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/**
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* insert_resource - Inserts a resource in the resource tree
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* @parent: parent of the new resource
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* @new: new resource to insert
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*
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* Returns 0 on success, -EBUSY if the resource can't be inserted.
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*
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* This function is equivalent to request_resource when no conflict
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* happens. If a conflict happens, and the conflicting resources
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* entirely fit within the range of the new resource, then the new
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* resource is inserted and the conflicting resources become children of
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* the new resource.
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/*
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* Insert a resource into the resource tree. If successful, return NULL,
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* otherwise return the conflicting resource (compare to __request_resource())
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*/
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int insert_resource(struct resource *parent, struct resource *new)
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static struct resource * __insert_resource(struct resource *parent, struct resource *new)
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{
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int result;
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struct resource *first, *next;
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write_lock(&resource_lock);
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for (;; parent = first) {
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result = 0;
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first = __request_resource(parent, new);
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if (!first)
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goto out;
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return first;
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result = -EBUSY;
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if (first == parent)
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goto out;
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return first;
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if ((first->start > new->start) || (first->end < new->end))
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break;
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@ -401,15 +387,13 @@ int insert_resource(struct resource *parent, struct resource *new)
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for (next = first; ; next = next->sibling) {
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/* Partial overlap? Bad, and unfixable */
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if (next->start < new->start || next->end > new->end)
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goto out;
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return next;
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if (!next->sibling)
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break;
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if (next->sibling->start > new->end)
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break;
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}
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result = 0;
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new->parent = parent;
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new->sibling = next->sibling;
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new->child = first;
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@ -426,10 +410,64 @@ int insert_resource(struct resource *parent, struct resource *new)
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next = next->sibling;
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next->sibling = new;
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}
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return NULL;
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}
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out:
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/**
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* insert_resource - Inserts a resource in the resource tree
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* @parent: parent of the new resource
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* @new: new resource to insert
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*
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* Returns 0 on success, -EBUSY if the resource can't be inserted.
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*
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* This function is equivalent to request_resource when no conflict
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* happens. If a conflict happens, and the conflicting resources
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* entirely fit within the range of the new resource, then the new
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* resource is inserted and the conflicting resources become children of
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* the new resource.
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*/
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int insert_resource(struct resource *parent, struct resource *new)
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{
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struct resource *conflict;
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write_lock(&resource_lock);
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conflict = __insert_resource(parent, new);
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write_unlock(&resource_lock);
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return conflict ? -EBUSY : 0;
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}
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/**
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* insert_resource_expand_to_fit - Insert a resource into the resource tree
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* @parent: parent of the new resource
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* @new: new resource to insert
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*
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* Insert a resource into the resource tree, possibly expanding it in order
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* to make it encompass any conflicting resources.
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*/
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void insert_resource_expand_to_fit(struct resource *root, struct resource *new)
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{
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if (new->parent)
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return;
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write_lock(&resource_lock);
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for (;;) {
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struct resource *conflict;
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conflict = __insert_resource(root, new);
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if (!conflict)
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break;
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if (conflict == root)
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break;
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/* Ok, expand resource to cover the conflict, then try again .. */
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if (conflict->start < new->start)
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new->start = conflict->start;
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if (conflict->end > new->end)
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new->end = conflict->end;
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printk("Expanded resource %s due to conflict with %s\n", new->name, conflict->name);
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}
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write_unlock(&resource_lock);
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return result;
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}
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/**
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