open-gpu-kernel-modules/kernel-open/nvidia-uvm/uvm_range_allocator.h

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    Copyright (c) 2016 NVIDIA Corporation

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#ifndef __UVM_RANGE_ALLOCATOR_H__
#define __UVM_RANGE_ALLOCATOR_H__

#include "uvm_range_tree.h"
#include "uvm_lock.h"

typedef struct {
    // Lock protecting the state of the range allocator
    uvm_spinlock_t lock;

    // Size of the range to allocate from
    NvU64 size;

    // Range tree tracking all the free ranges
    uvm_range_tree_t range_tree;
} uvm_range_allocator_t;

// A free range allocation
typedef struct {
    // The allocated start of the range
    NvU64 aligned_start;

    // A tree node allocated at the time of range allocation and used by the
    // range allocator when the range allocation is freed. This allows to
    // guarantee that uvm_range_allocator_free() always succeeds.
    uvm_range_tree_node_t *node;
} uvm_range_allocation_t;

// Initialize the range allocator with the given size
NV_STATUS uvm_range_allocator_init(NvU64 size, uvm_range_allocator_t *range_allocator);

// Deinitialize the range allocator
//
// All allocated ranges need to have been freed before the range allocator is deinitialized
void uvm_range_allocator_deinit(uvm_range_allocator_t *range_allocator);

// Alloc a free range of the given size and alignment
//
// Size needs to be greater or equal to 1.
// Alignment needs to be a power of 2 or 0. Alignment of 0 is converted into
// alignment of 1.
//
// On success, the start of the allocated range is returned in
// free_range_alloc->aligned_start.
NV_STATUS uvm_range_allocator_alloc(uvm_range_allocator_t *range_allocator, NvU64 size, NvU64 alignment, uvm_range_allocation_t *free_range_alloc);

// Free a previously allocated range
void uvm_range_allocator_free(uvm_range_allocator_t *range_allocator, uvm_range_allocation_t *range_alloc);

#endif // __UVM_RANGE_ALLOCATOR_H__