1 // SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
2 /* Copyright (c) 2004 Topspin Communications. All rights reserved.
3  * Copyright (c) 2005 - 2008 Mellanox Technologies. All rights reserved.
4  * Copyright (c) 2006 - 2007 Cisco Systems, Inc. All rights reserved.
5  * Copyright (c) 2020 NVIDIA CORPORATION. All rights reserved.
6  */
7 
8 #include "dr_types.h"
9 
mlx5dr_buddy_init(struct mlx5dr_icm_buddy_mem * buddy,unsigned int max_order)10 int mlx5dr_buddy_init(struct mlx5dr_icm_buddy_mem *buddy,
11 		      unsigned int max_order)
12 {
13 	int i;
14 
15 	buddy->max_order = max_order;
16 
17 	INIT_LIST_HEAD(&buddy->list_node);
18 	INIT_LIST_HEAD(&buddy->used_list);
19 	INIT_LIST_HEAD(&buddy->hot_list);
20 
21 	buddy->bitmap = kcalloc(buddy->max_order + 1,
22 				sizeof(*buddy->bitmap),
23 				GFP_KERNEL);
24 	buddy->num_free = kcalloc(buddy->max_order + 1,
25 				  sizeof(*buddy->num_free),
26 				  GFP_KERNEL);
27 
28 	if (!buddy->bitmap || !buddy->num_free)
29 		goto err_free_all;
30 
31 	/* Allocating max_order bitmaps, one for each order */
32 
33 	for (i = 0; i <= buddy->max_order; ++i) {
34 		unsigned int size = 1 << (buddy->max_order - i);
35 
36 		buddy->bitmap[i] = bitmap_zalloc(size, GFP_KERNEL);
37 		if (!buddy->bitmap[i])
38 			goto err_out_free_each_bit_per_order;
39 	}
40 
41 	/* In the beginning, we have only one order that is available for
42 	 * use (the biggest one), so mark the first bit in both bitmaps.
43 	 */
44 
45 	bitmap_set(buddy->bitmap[buddy->max_order], 0, 1);
46 
47 	buddy->num_free[buddy->max_order] = 1;
48 
49 	return 0;
50 
51 err_out_free_each_bit_per_order:
52 	for (i = 0; i <= buddy->max_order; ++i)
53 		bitmap_free(buddy->bitmap[i]);
54 
55 err_free_all:
56 	kfree(buddy->num_free);
57 	kfree(buddy->bitmap);
58 	return -ENOMEM;
59 }
60 
mlx5dr_buddy_cleanup(struct mlx5dr_icm_buddy_mem * buddy)61 void mlx5dr_buddy_cleanup(struct mlx5dr_icm_buddy_mem *buddy)
62 {
63 	int i;
64 
65 	list_del(&buddy->list_node);
66 
67 	for (i = 0; i <= buddy->max_order; ++i)
68 		bitmap_free(buddy->bitmap[i]);
69 
70 	kfree(buddy->num_free);
71 	kfree(buddy->bitmap);
72 }
73 
dr_buddy_find_free_seg(struct mlx5dr_icm_buddy_mem * buddy,unsigned int start_order,unsigned int * segment,unsigned int * order)74 static int dr_buddy_find_free_seg(struct mlx5dr_icm_buddy_mem *buddy,
75 				  unsigned int start_order,
76 				  unsigned int *segment,
77 				  unsigned int *order)
78 {
79 	unsigned int seg, order_iter, m;
80 
81 	for (order_iter = start_order;
82 	     order_iter <= buddy->max_order; ++order_iter) {
83 		if (!buddy->num_free[order_iter])
84 			continue;
85 
86 		m = 1 << (buddy->max_order - order_iter);
87 		seg = find_first_bit(buddy->bitmap[order_iter], m);
88 
89 		if (WARN(seg >= m,
90 			 "ICM Buddy: failed finding free mem for order %d\n",
91 			 order_iter))
92 			return -ENOMEM;
93 
94 		break;
95 	}
96 
97 	if (order_iter > buddy->max_order)
98 		return -ENOMEM;
99 
100 	*segment = seg;
101 	*order = order_iter;
102 	return 0;
103 }
104 
105 /**
106  * mlx5dr_buddy_alloc_mem() - Update second level bitmap.
107  * @buddy: Buddy to update.
108  * @order: Order of the buddy to update.
109  * @segment: Segment number.
110  *
111  * This function finds the first area of the ICM memory managed by this buddy.
112  * It uses the data structures of the buddy system in order to find the first
113  * area of free place, starting from the current order till the maximum order
114  * in the system.
115  *
116  * Return: 0 when segment is set, non-zero error status otherwise.
117  *
118  * The function returns the location (segment) in the whole buddy ICM memory
119  * area - the index of the memory segment that is available for use.
120  */
mlx5dr_buddy_alloc_mem(struct mlx5dr_icm_buddy_mem * buddy,unsigned int order,unsigned int * segment)121 int mlx5dr_buddy_alloc_mem(struct mlx5dr_icm_buddy_mem *buddy,
122 			   unsigned int order,
123 			   unsigned int *segment)
124 {
125 	unsigned int seg, order_iter;
126 	int err;
127 
128 	err = dr_buddy_find_free_seg(buddy, order, &seg, &order_iter);
129 	if (err)
130 		return err;
131 
132 	bitmap_clear(buddy->bitmap[order_iter], seg, 1);
133 	--buddy->num_free[order_iter];
134 
135 	/* If we found free memory in some order that is bigger than the
136 	 * required order, we need to split every order between the required
137 	 * order and the order that we found into two parts, and mark accordingly.
138 	 */
139 	while (order_iter > order) {
140 		--order_iter;
141 		seg <<= 1;
142 		bitmap_set(buddy->bitmap[order_iter], seg ^ 1, 1);
143 		++buddy->num_free[order_iter];
144 	}
145 
146 	seg <<= order;
147 	*segment = seg;
148 
149 	return 0;
150 }
151 
mlx5dr_buddy_free_mem(struct mlx5dr_icm_buddy_mem * buddy,unsigned int seg,unsigned int order)152 void mlx5dr_buddy_free_mem(struct mlx5dr_icm_buddy_mem *buddy,
153 			   unsigned int seg, unsigned int order)
154 {
155 	seg >>= order;
156 
157 	/* Whenever a segment is free,
158 	 * the mem is added to the buddy that gave it.
159 	 */
160 	while (test_bit(seg ^ 1, buddy->bitmap[order])) {
161 		bitmap_clear(buddy->bitmap[order], seg ^ 1, 1);
162 		--buddy->num_free[order];
163 		seg >>= 1;
164 		++order;
165 	}
166 	bitmap_set(buddy->bitmap[order], seg, 1);
167 
168 	++buddy->num_free[order];
169 }
170 
171