drm_vma_offset_lookup_locked
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Name

drm_vma_offset_lookup_locked — Find node in offset space

Synopsis

struct drm_vma_offset_node * drm_vma_offset_lookup_locked (struct drm_vma_offset_manager * mgr,
 unsigned long start,
 unsigned long pages);
 

Arguments

mgr

Manager object

start

Start address for object (page-based)

pages

Size of object (page-based)

Description

Find a node given a start address and object size. This returns the _best_ match for the given node. That is, start may point somewhere into a valid region and the given node will be returned, as long as the node spans the whole requested area (given the size in number of pages as pages).

Note that before lookup the vma offset manager lookup lock must be acquired with drm_vma_offset_lock_lookup. See there for an example. This can then be used to implement weakly referenced lookups using kref_get_unless_zero.

Example

       drm_vma_offset_lock_lookup(mgr);
       node = drm_vma_offset_lookup_locked(mgr);
       if (node)
           kref_get_unless_zero(container_of(node, sth, entr));
       drm_vma_offset_unlock_lookup(mgr);

RETURNS

Returns NULL if no suitable node can be found. Otherwise, the best match is returned. It's the caller's responsibility to make sure the node doesn't get destroyed before the caller can access it.

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