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320ae51f JA |
1 | #include <linux/kernel.h> |
2 | #include <linux/module.h> | |
3 | #include <linux/percpu_ida.h> | |
4 | ||
5 | #include <linux/blk-mq.h> | |
6 | #include "blk.h" | |
7 | #include "blk-mq.h" | |
8 | #include "blk-mq-tag.h" | |
9 | ||
10 | /* | |
11 | * Per tagged queue (tag address space) map | |
12 | */ | |
13 | struct blk_mq_tags { | |
14 | unsigned int nr_tags; | |
15 | unsigned int nr_reserved_tags; | |
16 | unsigned int nr_batch_move; | |
17 | unsigned int nr_max_cache; | |
18 | ||
19 | struct percpu_ida free_tags; | |
20 | struct percpu_ida reserved_tags; | |
21 | }; | |
22 | ||
23 | void blk_mq_wait_for_tags(struct blk_mq_tags *tags) | |
24 | { | |
25 | int tag = blk_mq_get_tag(tags, __GFP_WAIT, false); | |
26 | blk_mq_put_tag(tags, tag); | |
27 | } | |
28 | ||
29 | bool blk_mq_has_free_tags(struct blk_mq_tags *tags) | |
30 | { | |
31 | return !tags || | |
32 | percpu_ida_free_tags(&tags->free_tags, nr_cpu_ids) != 0; | |
33 | } | |
34 | ||
35 | static unsigned int __blk_mq_get_tag(struct blk_mq_tags *tags, gfp_t gfp) | |
36 | { | |
37 | int tag; | |
38 | ||
39 | tag = percpu_ida_alloc(&tags->free_tags, gfp); | |
40 | if (tag < 0) | |
41 | return BLK_MQ_TAG_FAIL; | |
42 | return tag + tags->nr_reserved_tags; | |
43 | } | |
44 | ||
45 | static unsigned int __blk_mq_get_reserved_tag(struct blk_mq_tags *tags, | |
46 | gfp_t gfp) | |
47 | { | |
48 | int tag; | |
49 | ||
50 | if (unlikely(!tags->nr_reserved_tags)) { | |
51 | WARN_ON_ONCE(1); | |
52 | return BLK_MQ_TAG_FAIL; | |
53 | } | |
54 | ||
55 | tag = percpu_ida_alloc(&tags->reserved_tags, gfp); | |
56 | if (tag < 0) | |
57 | return BLK_MQ_TAG_FAIL; | |
58 | return tag; | |
59 | } | |
60 | ||
61 | unsigned int blk_mq_get_tag(struct blk_mq_tags *tags, gfp_t gfp, bool reserved) | |
62 | { | |
63 | if (!reserved) | |
64 | return __blk_mq_get_tag(tags, gfp); | |
65 | ||
66 | return __blk_mq_get_reserved_tag(tags, gfp); | |
67 | } | |
68 | ||
69 | static void __blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag) | |
70 | { | |
71 | BUG_ON(tag >= tags->nr_tags); | |
72 | ||
73 | percpu_ida_free(&tags->free_tags, tag - tags->nr_reserved_tags); | |
74 | } | |
75 | ||
76 | static void __blk_mq_put_reserved_tag(struct blk_mq_tags *tags, | |
77 | unsigned int tag) | |
78 | { | |
79 | BUG_ON(tag >= tags->nr_reserved_tags); | |
80 | ||
81 | percpu_ida_free(&tags->reserved_tags, tag); | |
82 | } | |
83 | ||
84 | void blk_mq_put_tag(struct blk_mq_tags *tags, unsigned int tag) | |
85 | { | |
86 | if (tag >= tags->nr_reserved_tags) | |
87 | __blk_mq_put_tag(tags, tag); | |
88 | else | |
89 | __blk_mq_put_reserved_tag(tags, tag); | |
90 | } | |
91 | ||
92 | static int __blk_mq_tag_iter(unsigned id, void *data) | |
93 | { | |
94 | unsigned long *tag_map = data; | |
95 | __set_bit(id, tag_map); | |
96 | return 0; | |
97 | } | |
98 | ||
99 | void blk_mq_tag_busy_iter(struct blk_mq_tags *tags, | |
100 | void (*fn)(void *, unsigned long *), void *data) | |
101 | { | |
102 | unsigned long *tag_map; | |
103 | size_t map_size; | |
104 | ||
105 | map_size = ALIGN(tags->nr_tags, BITS_PER_LONG) / BITS_PER_LONG; | |
106 | tag_map = kzalloc(map_size * sizeof(unsigned long), GFP_ATOMIC); | |
107 | if (!tag_map) | |
108 | return; | |
109 | ||
110 | percpu_ida_for_each_free(&tags->free_tags, __blk_mq_tag_iter, tag_map); | |
111 | if (tags->nr_reserved_tags) | |
112 | percpu_ida_for_each_free(&tags->reserved_tags, __blk_mq_tag_iter, | |
113 | tag_map); | |
114 | ||
115 | fn(data, tag_map); | |
116 | kfree(tag_map); | |
117 | } | |
118 | ||
119 | struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, | |
120 | unsigned int reserved_tags, int node) | |
121 | { | |
122 | unsigned int nr_tags, nr_cache; | |
123 | struct blk_mq_tags *tags; | |
124 | int ret; | |
125 | ||
126 | if (total_tags > BLK_MQ_TAG_MAX) { | |
127 | pr_err("blk-mq: tag depth too large\n"); | |
128 | return NULL; | |
129 | } | |
130 | ||
131 | tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node); | |
132 | if (!tags) | |
133 | return NULL; | |
134 | ||
135 | nr_tags = total_tags - reserved_tags; | |
136 | nr_cache = nr_tags / num_possible_cpus(); | |
137 | ||
138 | if (nr_cache < BLK_MQ_TAG_CACHE_MIN) | |
139 | nr_cache = BLK_MQ_TAG_CACHE_MIN; | |
140 | else if (nr_cache > BLK_MQ_TAG_CACHE_MAX) | |
141 | nr_cache = BLK_MQ_TAG_CACHE_MAX; | |
142 | ||
143 | tags->nr_tags = total_tags; | |
144 | tags->nr_reserved_tags = reserved_tags; | |
145 | tags->nr_max_cache = nr_cache; | |
146 | tags->nr_batch_move = max(1u, nr_cache / 2); | |
147 | ||
148 | ret = __percpu_ida_init(&tags->free_tags, tags->nr_tags - | |
149 | tags->nr_reserved_tags, | |
150 | tags->nr_max_cache, | |
151 | tags->nr_batch_move); | |
152 | if (ret) | |
153 | goto err_free_tags; | |
154 | ||
155 | if (reserved_tags) { | |
156 | /* | |
157 | * With max_cahe and batch set to 1, the allocator fallbacks to | |
158 | * no cached. It's fine reserved tags allocation is slow. | |
159 | */ | |
160 | ret = __percpu_ida_init(&tags->reserved_tags, reserved_tags, | |
161 | 1, 1); | |
162 | if (ret) | |
163 | goto err_reserved_tags; | |
164 | } | |
165 | ||
166 | return tags; | |
167 | ||
168 | err_reserved_tags: | |
169 | percpu_ida_destroy(&tags->free_tags); | |
170 | err_free_tags: | |
171 | kfree(tags); | |
172 | return NULL; | |
173 | } | |
174 | ||
175 | void blk_mq_free_tags(struct blk_mq_tags *tags) | |
176 | { | |
177 | percpu_ida_destroy(&tags->free_tags); | |
178 | percpu_ida_destroy(&tags->reserved_tags); | |
179 | kfree(tags); | |
180 | } | |
181 | ||
182 | ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page) | |
183 | { | |
184 | char *orig_page = page; | |
11c94444 | 185 | unsigned int cpu; |
320ae51f JA |
186 | |
187 | if (!tags) | |
188 | return 0; | |
189 | ||
190 | page += sprintf(page, "nr_tags=%u, reserved_tags=%u, batch_move=%u," | |
191 | " max_cache=%u\n", tags->nr_tags, tags->nr_reserved_tags, | |
192 | tags->nr_batch_move, tags->nr_max_cache); | |
193 | ||
194 | page += sprintf(page, "nr_free=%u, nr_reserved=%u\n", | |
195 | percpu_ida_free_tags(&tags->free_tags, nr_cpu_ids), | |
196 | percpu_ida_free_tags(&tags->reserved_tags, nr_cpu_ids)); | |
197 | ||
198 | for_each_possible_cpu(cpu) { | |
199 | page += sprintf(page, " cpu%02u: nr_free=%u\n", cpu, | |
200 | percpu_ida_free_tags(&tags->free_tags, cpu)); | |
201 | } | |
202 | ||
203 | return page - orig_page; | |
204 | } |