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