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Linux/block/blk-mq-tag.c

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Diff markup

Differences between /block/blk-mq-tag.c (Version linux-4.17.19) and /block/blk-mq-tag.c (Version linux-4.12.14)


  1 /*                                                  1 /*
  2  * Tag allocation using scalable bitmaps. Uses      2  * Tag allocation using scalable bitmaps. Uses active queue tracking to support
  3  * fairer distribution of tags between multipl      3  * fairer distribution of tags between multiple submitters when a shared tag map
  4  * is used.                                         4  * is used.
  5  *                                                  5  *
  6  * Copyright (C) 2013-2014 Jens Axboe               6  * Copyright (C) 2013-2014 Jens Axboe
  7  */                                                 7  */
  8 #include <linux/kernel.h>                           8 #include <linux/kernel.h>
  9 #include <linux/module.h>                           9 #include <linux/module.h>
 10                                                    10 
 11 #include <linux/blk-mq.h>                          11 #include <linux/blk-mq.h>
 12 #include "blk.h"                                   12 #include "blk.h"
 13 #include "blk-mq.h"                                13 #include "blk-mq.h"
 14 #include "blk-mq-tag.h"                            14 #include "blk-mq-tag.h"
 15                                                    15 
 16 bool blk_mq_has_free_tags(struct blk_mq_tags *     16 bool blk_mq_has_free_tags(struct blk_mq_tags *tags)
 17 {                                                  17 {
 18         if (!tags)                                 18         if (!tags)
 19                 return true;                       19                 return true;
 20                                                    20 
 21         return sbitmap_any_bit_clear(&tags->bi     21         return sbitmap_any_bit_clear(&tags->bitmap_tags.sb);
 22 }                                                  22 }
 23                                                    23 
 24 /*                                                 24 /*
 25  * If a previously inactive queue goes active,     25  * If a previously inactive queue goes active, bump the active user count.
 26  */                                                26  */
 27 bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *h     27 bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
 28 {                                                  28 {
 29         if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hc     29         if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state) &&
 30             !test_and_set_bit(BLK_MQ_S_TAG_ACT     30             !test_and_set_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
 31                 atomic_inc(&hctx->tags->active     31                 atomic_inc(&hctx->tags->active_queues);
 32                                                    32 
 33         return true;                               33         return true;
 34 }                                                  34 }
 35                                                    35 
 36 /*                                                 36 /*
 37  * Wakeup all potentially sleeping on tags         37  * Wakeup all potentially sleeping on tags
 38  */                                                38  */
 39 void blk_mq_tag_wakeup_all(struct blk_mq_tags      39 void blk_mq_tag_wakeup_all(struct blk_mq_tags *tags, bool include_reserve)
 40 {                                                  40 {
 41         sbitmap_queue_wake_all(&tags->bitmap_t     41         sbitmap_queue_wake_all(&tags->bitmap_tags);
 42         if (include_reserve)                       42         if (include_reserve)
 43                 sbitmap_queue_wake_all(&tags->     43                 sbitmap_queue_wake_all(&tags->breserved_tags);
 44 }                                                  44 }
 45                                                    45 
 46 /*                                                 46 /*
 47  * If a previously busy queue goes inactive, p     47  * If a previously busy queue goes inactive, potential waiters could now
 48  * be allowed to queue. Wake them up and check     48  * be allowed to queue. Wake them up and check.
 49  */                                                49  */
 50 void __blk_mq_tag_idle(struct blk_mq_hw_ctx *h     50 void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
 51 {                                                  51 {
 52         struct blk_mq_tags *tags = hctx->tags;     52         struct blk_mq_tags *tags = hctx->tags;
 53                                                    53 
 54         if (!test_and_clear_bit(BLK_MQ_S_TAG_A     54         if (!test_and_clear_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
 55                 return;                            55                 return;
 56                                                    56 
 57         atomic_dec(&tags->active_queues);          57         atomic_dec(&tags->active_queues);
 58                                                    58 
 59         blk_mq_tag_wakeup_all(tags, false);        59         blk_mq_tag_wakeup_all(tags, false);
 60 }                                                  60 }
 61                                                    61 
 62 /*                                                 62 /*
 63  * For shared tag users, we track the number o     63  * For shared tag users, we track the number of currently active users
 64  * and attempt to provide a fair share of the      64  * and attempt to provide a fair share of the tag depth for each of them.
 65  */                                                65  */
 66 static inline bool hctx_may_queue(struct blk_m     66 static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx,
 67                                   struct sbitm     67                                   struct sbitmap_queue *bt)
 68 {                                                  68 {
 69         unsigned int depth, users;                 69         unsigned int depth, users;
 70                                                    70 
 71         if (!hctx || !(hctx->flags & BLK_MQ_F_     71         if (!hctx || !(hctx->flags & BLK_MQ_F_TAG_SHARED))
 72                 return true;                       72                 return true;
 73         if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hc     73         if (!test_bit(BLK_MQ_S_TAG_ACTIVE, &hctx->state))
 74                 return true;                       74                 return true;
 75                                                    75 
 76         /*                                         76         /*
 77          * Don't try dividing an ant               77          * Don't try dividing an ant
 78          */                                        78          */
 79         if (bt->sb.depth == 1)                     79         if (bt->sb.depth == 1)
 80                 return true;                       80                 return true;
 81                                                    81 
 82         users = atomic_read(&hctx->tags->activ     82         users = atomic_read(&hctx->tags->active_queues);
 83         if (!users)                                83         if (!users)
 84                 return true;                       84                 return true;
 85                                                    85 
 86         /*                                         86         /*
 87          * Allow at least some tags                87          * Allow at least some tags
 88          */                                        88          */
 89         depth = max((bt->sb.depth + users - 1)     89         depth = max((bt->sb.depth + users - 1) / users, 4U);
 90         return atomic_read(&hctx->nr_active) <     90         return atomic_read(&hctx->nr_active) < depth;
 91 }                                                  91 }
 92                                                    92 
 93 static int __blk_mq_get_tag(struct blk_mq_allo     93 static int __blk_mq_get_tag(struct blk_mq_alloc_data *data,
 94                             struct sbitmap_que     94                             struct sbitmap_queue *bt)
 95 {                                                  95 {
 96         if (!(data->flags & BLK_MQ_REQ_INTERNA     96         if (!(data->flags & BLK_MQ_REQ_INTERNAL) &&
 97             !hctx_may_queue(data->hctx, bt))       97             !hctx_may_queue(data->hctx, bt))
 98                 return -1;                         98                 return -1;
 99         if (data->shallow_depth)                   99         if (data->shallow_depth)
100                 return __sbitmap_queue_get_sha    100                 return __sbitmap_queue_get_shallow(bt, data->shallow_depth);
101         else                                      101         else
102                 return __sbitmap_queue_get(bt)    102                 return __sbitmap_queue_get(bt);
103 }                                                 103 }
104                                                   104 
105 unsigned int blk_mq_get_tag(struct blk_mq_allo    105 unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data)
106 {                                                 106 {
107         struct blk_mq_tags *tags = blk_mq_tags    107         struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
108         struct sbitmap_queue *bt;                 108         struct sbitmap_queue *bt;
109         struct sbq_wait_state *ws;                109         struct sbq_wait_state *ws;
110         DEFINE_WAIT(wait);                        110         DEFINE_WAIT(wait);
111         unsigned int tag_offset;                  111         unsigned int tag_offset;
112         bool drop_ctx;                            112         bool drop_ctx;
113         int tag;                                  113         int tag;
114                                                   114 
115         if (data->flags & BLK_MQ_REQ_RESERVED)    115         if (data->flags & BLK_MQ_REQ_RESERVED) {
116                 if (unlikely(!tags->nr_reserve    116                 if (unlikely(!tags->nr_reserved_tags)) {
117                         WARN_ON_ONCE(1);          117                         WARN_ON_ONCE(1);
118                         return BLK_MQ_TAG_FAIL    118                         return BLK_MQ_TAG_FAIL;
119                 }                                 119                 }
120                 bt = &tags->breserved_tags;       120                 bt = &tags->breserved_tags;
121                 tag_offset = 0;                   121                 tag_offset = 0;
122         } else {                                  122         } else {
123                 bt = &tags->bitmap_tags;          123                 bt = &tags->bitmap_tags;
124                 tag_offset = tags->nr_reserved    124                 tag_offset = tags->nr_reserved_tags;
125         }                                         125         }
126                                                   126 
127         tag = __blk_mq_get_tag(data, bt);         127         tag = __blk_mq_get_tag(data, bt);
128         if (tag != -1)                            128         if (tag != -1)
129                 goto found_tag;                   129                 goto found_tag;
130                                                   130 
131         if (data->flags & BLK_MQ_REQ_NOWAIT)      131         if (data->flags & BLK_MQ_REQ_NOWAIT)
132                 return BLK_MQ_TAG_FAIL;           132                 return BLK_MQ_TAG_FAIL;
133                                                   133 
134         ws = bt_wait_ptr(bt, data->hctx);         134         ws = bt_wait_ptr(bt, data->hctx);
135         drop_ctx = data->ctx == NULL;             135         drop_ctx = data->ctx == NULL;
136         do {                                      136         do {
                                                   >> 137                 prepare_to_wait(&ws->wait, &wait, TASK_UNINTERRUPTIBLE);
                                                   >> 138 
                                                   >> 139                 tag = __blk_mq_get_tag(data, bt);
                                                   >> 140                 if (tag != -1)
                                                   >> 141                         break;
                                                   >> 142 
137                 /*                                143                 /*
138                  * We're out of tags on this h    144                  * We're out of tags on this hardware queue, kick any
139                  * pending IO submits before g    145                  * pending IO submits before going to sleep waiting for
140                  * some to complete.              146                  * some to complete.
141                  */                               147                  */
142                 blk_mq_run_hw_queue(data->hctx    148                 blk_mq_run_hw_queue(data->hctx, false);
143                                                   149 
144                 /*                                150                 /*
145                  * Retry tag allocation after     151                  * Retry tag allocation after running the hardware queue,
146                  * as running the queue may al    152                  * as running the queue may also have found completions.
147                  */                               153                  */
148                 tag = __blk_mq_get_tag(data, b    154                 tag = __blk_mq_get_tag(data, bt);
149                 if (tag != -1)                    155                 if (tag != -1)
150                         break;                    156                         break;
151                                                   157 
152                 prepare_to_wait_exclusive(&ws- << 
153                                                << 
154                                                << 
155                 tag = __blk_mq_get_tag(data, b << 
156                 if (tag != -1)                 << 
157                         break;                 << 
158                                                << 
159                 if (data->ctx)                    158                 if (data->ctx)
160                         blk_mq_put_ctx(data->c    159                         blk_mq_put_ctx(data->ctx);
161                                                   160 
162                 io_schedule();                    161                 io_schedule();
163                                                   162 
164                 data->ctx = blk_mq_get_ctx(dat    163                 data->ctx = blk_mq_get_ctx(data->q);
165                 data->hctx = blk_mq_map_queue(    164                 data->hctx = blk_mq_map_queue(data->q, data->ctx->cpu);
166                 tags = blk_mq_tags_from_data(d    165                 tags = blk_mq_tags_from_data(data);
167                 if (data->flags & BLK_MQ_REQ_R    166                 if (data->flags & BLK_MQ_REQ_RESERVED)
168                         bt = &tags->breserved_    167                         bt = &tags->breserved_tags;
169                 else                              168                 else
170                         bt = &tags->bitmap_tag    169                         bt = &tags->bitmap_tags;
171                                                   170 
172                 finish_wait(&ws->wait, &wait);    171                 finish_wait(&ws->wait, &wait);
173                 ws = bt_wait_ptr(bt, data->hct    172                 ws = bt_wait_ptr(bt, data->hctx);
174         } while (1);                              173         } while (1);
175                                                   174 
176         if (drop_ctx && data->ctx)                175         if (drop_ctx && data->ctx)
177                 blk_mq_put_ctx(data->ctx);        176                 blk_mq_put_ctx(data->ctx);
178                                                   177 
179         finish_wait(&ws->wait, &wait);            178         finish_wait(&ws->wait, &wait);
180                                                   179 
181 found_tag:                                        180 found_tag:
182         return tag + tag_offset;                  181         return tag + tag_offset;
183 }                                                 182 }
184                                                   183 
185 void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx    184 void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
186                     struct blk_mq_ctx *ctx, un    185                     struct blk_mq_ctx *ctx, unsigned int tag)
187 {                                                 186 {
188         if (!blk_mq_tag_is_reserved(tags, tag)    187         if (!blk_mq_tag_is_reserved(tags, tag)) {
189                 const int real_tag = tag - tag    188                 const int real_tag = tag - tags->nr_reserved_tags;
190                                                   189 
191                 BUG_ON(real_tag >= tags->nr_ta    190                 BUG_ON(real_tag >= tags->nr_tags);
192                 sbitmap_queue_clear(&tags->bit    191                 sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
193         } else {                                  192         } else {
194                 BUG_ON(tag >= tags->nr_reserve    193                 BUG_ON(tag >= tags->nr_reserved_tags);
195                 sbitmap_queue_clear(&tags->bre    194                 sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
196         }                                         195         }
197 }                                                 196 }
198                                                   197 
199 struct bt_iter_data {                             198 struct bt_iter_data {
200         struct blk_mq_hw_ctx *hctx;               199         struct blk_mq_hw_ctx *hctx;
201         busy_iter_fn *fn;                         200         busy_iter_fn *fn;
202         void *data;                               201         void *data;
203         bool reserved;                            202         bool reserved;
204 };                                                203 };
205                                                   204 
206 static bool bt_iter(struct sbitmap *bitmap, un    205 static bool bt_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
207 {                                                 206 {
208         struct bt_iter_data *iter_data = data;    207         struct bt_iter_data *iter_data = data;
209         struct blk_mq_hw_ctx *hctx = iter_data    208         struct blk_mq_hw_ctx *hctx = iter_data->hctx;
210         struct blk_mq_tags *tags = hctx->tags;    209         struct blk_mq_tags *tags = hctx->tags;
211         bool reserved = iter_data->reserved;      210         bool reserved = iter_data->reserved;
212         struct request *rq;                       211         struct request *rq;
213                                                   212 
214         if (!reserved)                            213         if (!reserved)
215                 bitnr += tags->nr_reserved_tag    214                 bitnr += tags->nr_reserved_tags;
216         rq = tags->rqs[bitnr];                    215         rq = tags->rqs[bitnr];
217                                                   216 
218         /*                                     !! 217         if (rq->q == hctx->queue)
219          * We can hit rq == NULL here, because << 
220          * test and set the bit before assinin << 
221          */                                    << 
222         if (rq && rq->q == hctx->queue)        << 
223                 iter_data->fn(hctx, rq, iter_d    218                 iter_data->fn(hctx, rq, iter_data->data, reserved);
224         return true;                              219         return true;
225 }                                                 220 }
226                                                   221 
227 static void bt_for_each(struct blk_mq_hw_ctx *    222 static void bt_for_each(struct blk_mq_hw_ctx *hctx, struct sbitmap_queue *bt,
228                         busy_iter_fn *fn, void    223                         busy_iter_fn *fn, void *data, bool reserved)
229 {                                                 224 {
230         struct bt_iter_data iter_data = {         225         struct bt_iter_data iter_data = {
231                 .hctx = hctx,                     226                 .hctx = hctx,
232                 .fn = fn,                         227                 .fn = fn,
233                 .data = data,                     228                 .data = data,
234                 .reserved = reserved,             229                 .reserved = reserved,
235         };                                        230         };
236                                                   231 
237         sbitmap_for_each_set(&bt->sb, bt_iter,    232         sbitmap_for_each_set(&bt->sb, bt_iter, &iter_data);
238 }                                                 233 }
239                                                   234 
240 struct bt_tags_iter_data {                        235 struct bt_tags_iter_data {
241         struct blk_mq_tags *tags;                 236         struct blk_mq_tags *tags;
242         busy_tag_iter_fn *fn;                     237         busy_tag_iter_fn *fn;
243         void *data;                               238         void *data;
244         bool reserved;                            239         bool reserved;
245 };                                                240 };
246                                                   241 
247 static bool bt_tags_iter(struct sbitmap *bitma    242 static bool bt_tags_iter(struct sbitmap *bitmap, unsigned int bitnr, void *data)
248 {                                                 243 {
249         struct bt_tags_iter_data *iter_data =     244         struct bt_tags_iter_data *iter_data = data;
250         struct blk_mq_tags *tags = iter_data->    245         struct blk_mq_tags *tags = iter_data->tags;
251         bool reserved = iter_data->reserved;      246         bool reserved = iter_data->reserved;
252         struct request *rq;                       247         struct request *rq;
253                                                   248 
254         if (!reserved)                            249         if (!reserved)
255                 bitnr += tags->nr_reserved_tag    250                 bitnr += tags->nr_reserved_tags;
256                                                << 
257         /*                                     << 
258          * We can hit rq == NULL here, because << 
259          * test and set the bit before assinin << 
260          */                                    << 
261         rq = tags->rqs[bitnr];                    251         rq = tags->rqs[bitnr];
262         if (rq)                                << 
263                 iter_data->fn(rq, iter_data->d << 
264                                                   252 
                                                   >> 253         iter_data->fn(rq, iter_data->data, reserved);
265         return true;                              254         return true;
266 }                                                 255 }
267                                                   256 
268 static void bt_tags_for_each(struct blk_mq_tag    257 static void bt_tags_for_each(struct blk_mq_tags *tags, struct sbitmap_queue *bt,
269                              busy_tag_iter_fn     258                              busy_tag_iter_fn *fn, void *data, bool reserved)
270 {                                                 259 {
271         struct bt_tags_iter_data iter_data = {    260         struct bt_tags_iter_data iter_data = {
272                 .tags = tags,                     261                 .tags = tags,
273                 .fn = fn,                         262                 .fn = fn,
274                 .data = data,                     263                 .data = data,
275                 .reserved = reserved,             264                 .reserved = reserved,
276         };                                        265         };
277                                                   266 
278         if (tags->rqs)                            267         if (tags->rqs)
279                 sbitmap_for_each_set(&bt->sb,     268                 sbitmap_for_each_set(&bt->sb, bt_tags_iter, &iter_data);
280 }                                                 269 }
281                                                   270 
282 static void blk_mq_all_tag_busy_iter(struct bl    271 static void blk_mq_all_tag_busy_iter(struct blk_mq_tags *tags,
283                 busy_tag_iter_fn *fn, void *pr    272                 busy_tag_iter_fn *fn, void *priv)
284 {                                                 273 {
285         if (tags->nr_reserved_tags)               274         if (tags->nr_reserved_tags)
286                 bt_tags_for_each(tags, &tags->    275                 bt_tags_for_each(tags, &tags->breserved_tags, fn, priv, true);
287         bt_tags_for_each(tags, &tags->bitmap_t    276         bt_tags_for_each(tags, &tags->bitmap_tags, fn, priv, false);
288 }                                                 277 }
289                                                   278 
290 void blk_mq_tagset_busy_iter(struct blk_mq_tag    279 void blk_mq_tagset_busy_iter(struct blk_mq_tag_set *tagset,
291                 busy_tag_iter_fn *fn, void *pr    280                 busy_tag_iter_fn *fn, void *priv)
292 {                                                 281 {
293         int i;                                    282         int i;
294                                                   283 
295         for (i = 0; i < tagset->nr_hw_queues;     284         for (i = 0; i < tagset->nr_hw_queues; i++) {
296                 if (tagset->tags && tagset->ta    285                 if (tagset->tags && tagset->tags[i])
297                         blk_mq_all_tag_busy_it    286                         blk_mq_all_tag_busy_iter(tagset->tags[i], fn, priv);
298         }                                         287         }
299 }                                                 288 }
300 EXPORT_SYMBOL(blk_mq_tagset_busy_iter);           289 EXPORT_SYMBOL(blk_mq_tagset_busy_iter);
301                                                   290 
302 int blk_mq_tagset_iter(struct blk_mq_tag_set * !! 291 int blk_mq_reinit_tagset(struct blk_mq_tag_set *set)
303                          int (fn)(void *, stru << 
304 {                                                 292 {
305         int i, j, ret = 0;                        293         int i, j, ret = 0;
306                                                   294 
307         if (WARN_ON_ONCE(!fn))                 !! 295         if (!set->ops->reinit_request)
308                 goto out;                         296                 goto out;
309                                                   297 
310         for (i = 0; i < set->nr_hw_queues; i++    298         for (i = 0; i < set->nr_hw_queues; i++) {
311                 struct blk_mq_tags *tags = set    299                 struct blk_mq_tags *tags = set->tags[i];
312                                                   300 
313                 if (!tags)                        301                 if (!tags)
314                         continue;                 302                         continue;
315                                                   303 
316                 for (j = 0; j < tags->nr_tags;    304                 for (j = 0; j < tags->nr_tags; j++) {
317                         if (!tags->static_rqs[    305                         if (!tags->static_rqs[j])
318                                 continue;         306                                 continue;
319                                                   307 
320                         ret = fn(data, tags->s !! 308                         ret = set->ops->reinit_request(set->driver_data,
                                                   >> 309                                                 tags->static_rqs[j]);
321                         if (ret)                  310                         if (ret)
322                                 goto out;         311                                 goto out;
323                 }                                 312                 }
324         }                                         313         }
325                                                   314 
326 out:                                              315 out:
327         return ret;                               316         return ret;
328 }                                                 317 }
329 EXPORT_SYMBOL_GPL(blk_mq_tagset_iter);         !! 318 EXPORT_SYMBOL_GPL(blk_mq_reinit_tagset);
330                                                   319 
331 void blk_mq_queue_tag_busy_iter(struct request    320 void blk_mq_queue_tag_busy_iter(struct request_queue *q, busy_iter_fn *fn,
332                 void *priv)                       321                 void *priv)
333 {                                                 322 {
334         struct blk_mq_hw_ctx *hctx;               323         struct blk_mq_hw_ctx *hctx;
335         int i;                                    324         int i;
336                                                   325 
337                                                   326 
338         queue_for_each_hw_ctx(q, hctx, i) {       327         queue_for_each_hw_ctx(q, hctx, i) {
339                 struct blk_mq_tags *tags = hct    328                 struct blk_mq_tags *tags = hctx->tags;
340                                                   329 
341                 /*                                330                 /*
342                  * If not software queues are     331                  * If not software queues are currently mapped to this
343                  * hardware queue, there's not    332                  * hardware queue, there's nothing to check
344                  */                               333                  */
345                 if (!blk_mq_hw_queue_mapped(hc    334                 if (!blk_mq_hw_queue_mapped(hctx))
346                         continue;                 335                         continue;
347                                                   336 
348                 if (tags->nr_reserved_tags)       337                 if (tags->nr_reserved_tags)
349                         bt_for_each(hctx, &tag    338                         bt_for_each(hctx, &tags->breserved_tags, fn, priv, true);
350                 bt_for_each(hctx, &tags->bitma    339                 bt_for_each(hctx, &tags->bitmap_tags, fn, priv, false);
351         }                                         340         }
352                                                   341 
353 }                                                 342 }
354                                                   343 
355 static int bt_alloc(struct sbitmap_queue *bt,     344 static int bt_alloc(struct sbitmap_queue *bt, unsigned int depth,
356                     bool round_robin, int node    345                     bool round_robin, int node)
357 {                                                 346 {
358         return sbitmap_queue_init_node(bt, dep    347         return sbitmap_queue_init_node(bt, depth, -1, round_robin, GFP_KERNEL,
359                                        node);     348                                        node);
360 }                                                 349 }
361                                                   350 
362 static struct blk_mq_tags *blk_mq_init_bitmap_    351 static struct blk_mq_tags *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags,
363                                                   352                                                    int node, int alloc_policy)
364 {                                                 353 {
365         unsigned int depth = tags->nr_tags - t    354         unsigned int depth = tags->nr_tags - tags->nr_reserved_tags;
366         bool round_robin = alloc_policy == BLK    355         bool round_robin = alloc_policy == BLK_TAG_ALLOC_RR;
367                                                   356 
368         if (bt_alloc(&tags->bitmap_tags, depth    357         if (bt_alloc(&tags->bitmap_tags, depth, round_robin, node))
369                 goto free_tags;                   358                 goto free_tags;
370         if (bt_alloc(&tags->breserved_tags, ta    359         if (bt_alloc(&tags->breserved_tags, tags->nr_reserved_tags, round_robin,
371                      node))                       360                      node))
372                 goto free_bitmap_tags;            361                 goto free_bitmap_tags;
373                                                   362 
374         return tags;                              363         return tags;
375 free_bitmap_tags:                                 364 free_bitmap_tags:
376         sbitmap_queue_free(&tags->bitmap_tags)    365         sbitmap_queue_free(&tags->bitmap_tags);
377 free_tags:                                        366 free_tags:
378         kfree(tags);                              367         kfree(tags);
379         return NULL;                              368         return NULL;
380 }                                                 369 }
381                                                   370 
382 struct blk_mq_tags *blk_mq_init_tags(unsigned     371 struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags,
383                                      unsigned     372                                      unsigned int reserved_tags,
384                                      int node,    373                                      int node, int alloc_policy)
385 {                                                 374 {
386         struct blk_mq_tags *tags;                 375         struct blk_mq_tags *tags;
387                                                   376 
388         if (total_tags > BLK_MQ_TAG_MAX) {        377         if (total_tags > BLK_MQ_TAG_MAX) {
389                 pr_err("blk-mq: tag depth too     378                 pr_err("blk-mq: tag depth too large\n");
390                 return NULL;                      379                 return NULL;
391         }                                         380         }
392                                                   381 
393         tags = kzalloc_node(sizeof(*tags), GFP    382         tags = kzalloc_node(sizeof(*tags), GFP_KERNEL, node);
394         if (!tags)                                383         if (!tags)
395                 return NULL;                      384                 return NULL;
396                                                   385 
397         tags->nr_tags = total_tags;               386         tags->nr_tags = total_tags;
398         tags->nr_reserved_tags = reserved_tags    387         tags->nr_reserved_tags = reserved_tags;
399                                                   388 
400         return blk_mq_init_bitmap_tags(tags, n    389         return blk_mq_init_bitmap_tags(tags, node, alloc_policy);
401 }                                                 390 }
402                                                   391 
403 void blk_mq_free_tags(struct blk_mq_tags *tags    392 void blk_mq_free_tags(struct blk_mq_tags *tags)
404 {                                                 393 {
405         sbitmap_queue_free(&tags->bitmap_tags)    394         sbitmap_queue_free(&tags->bitmap_tags);
406         sbitmap_queue_free(&tags->breserved_ta    395         sbitmap_queue_free(&tags->breserved_tags);
407         kfree(tags);                              396         kfree(tags);
408 }                                                 397 }
409                                                   398 
410 int blk_mq_tag_update_depth(struct blk_mq_hw_c    399 int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
411                             struct blk_mq_tags    400                             struct blk_mq_tags **tagsptr, unsigned int tdepth,
412                             bool can_grow)        401                             bool can_grow)
413 {                                                 402 {
414         struct blk_mq_tags *tags = *tagsptr;      403         struct blk_mq_tags *tags = *tagsptr;
415                                                   404 
416         if (tdepth <= tags->nr_reserved_tags)     405         if (tdepth <= tags->nr_reserved_tags)
417                 return -EINVAL;                   406                 return -EINVAL;
418                                                   407 
419         tdepth -= tags->nr_reserved_tags;         408         tdepth -= tags->nr_reserved_tags;
420                                                   409 
421         /*                                        410         /*
422          * If we are allowed to grow beyond th    411          * If we are allowed to grow beyond the original size, allocate
423          * a new set of tags before freeing th    412          * a new set of tags before freeing the old one.
424          */                                       413          */
425         if (tdepth > tags->nr_tags) {             414         if (tdepth > tags->nr_tags) {
426                 struct blk_mq_tag_set *set = h    415                 struct blk_mq_tag_set *set = hctx->queue->tag_set;
427                 struct blk_mq_tags *new;          416                 struct blk_mq_tags *new;
428                 bool ret;                         417                 bool ret;
429                                                   418 
430                 if (!can_grow)                    419                 if (!can_grow)
431                         return -EINVAL;           420                         return -EINVAL;
432                                                   421 
433                 /*                                422                 /*
434                  * We need some sort of upper     423                  * We need some sort of upper limit, set it high enough that
435                  * no valid use cases should r    424                  * no valid use cases should require more.
436                  */                               425                  */
437                 if (tdepth > 16 * BLKDEV_MAX_R    426                 if (tdepth > 16 * BLKDEV_MAX_RQ)
438                         return -EINVAL;           427                         return -EINVAL;
439                                                   428 
440                 new = blk_mq_alloc_rq_map(set,    429                 new = blk_mq_alloc_rq_map(set, hctx->queue_num, tdepth, 0);
441                 if (!new)                         430                 if (!new)
442                         return -ENOMEM;           431                         return -ENOMEM;
443                 ret = blk_mq_alloc_rqs(set, ne    432                 ret = blk_mq_alloc_rqs(set, new, hctx->queue_num, tdepth);
444                 if (ret) {                        433                 if (ret) {
445                         blk_mq_free_rq_map(new    434                         blk_mq_free_rq_map(new);
446                         return -ENOMEM;           435                         return -ENOMEM;
447                 }                                 436                 }
448                                                   437 
449                 blk_mq_free_rqs(set, *tagsptr,    438                 blk_mq_free_rqs(set, *tagsptr, hctx->queue_num);
450                 blk_mq_free_rq_map(*tagsptr);     439                 blk_mq_free_rq_map(*tagsptr);
451                 *tagsptr = new;                   440                 *tagsptr = new;
452         } else {                                  441         } else {
453                 /*                                442                 /*
454                  * Don't need (or can't) updat    443                  * Don't need (or can't) update reserved tags here, they
455                  * remain static and should ne    444                  * remain static and should never need resizing.
456                  */                               445                  */
457                 sbitmap_queue_resize(&tags->bi    446                 sbitmap_queue_resize(&tags->bitmap_tags, tdepth);
458         }                                         447         }
459                                                   448 
460         return 0;                                 449         return 0;
461 }                                                 450 }
462                                                   451 
463 /**                                               452 /**
464  * blk_mq_unique_tag() - return a tag that is     453  * blk_mq_unique_tag() - return a tag that is unique queue-wide
465  * @rq: request for which to compute a unique     454  * @rq: request for which to compute a unique tag
466  *                                                455  *
467  * The tag field in struct request is unique p    456  * The tag field in struct request is unique per hardware queue but not over
468  * all hardware queues. Hence this function th    457  * all hardware queues. Hence this function that returns a tag with the
469  * hardware context index in the upper bits an    458  * hardware context index in the upper bits and the per hardware queue tag in
470  * the lower bits.                                459  * the lower bits.
471  *                                                460  *
472  * Note: When called for a request that is que    461  * Note: When called for a request that is queued on a non-multiqueue request
473  * queue, the hardware context index is set to    462  * queue, the hardware context index is set to zero.
474  */                                               463  */
475 u32 blk_mq_unique_tag(struct request *rq)         464 u32 blk_mq_unique_tag(struct request *rq)
476 {                                                 465 {
477         struct request_queue *q = rq->q;          466         struct request_queue *q = rq->q;
478         struct blk_mq_hw_ctx *hctx;               467         struct blk_mq_hw_ctx *hctx;
479         int hwq = 0;                              468         int hwq = 0;
480                                                   469 
481         if (q->mq_ops) {                          470         if (q->mq_ops) {
482                 hctx = blk_mq_map_queue(q, rq-    471                 hctx = blk_mq_map_queue(q, rq->mq_ctx->cpu);
483                 hwq = hctx->queue_num;            472                 hwq = hctx->queue_num;
484         }                                         473         }
485                                                   474 
486         return (hwq << BLK_MQ_UNIQUE_TAG_BITS)    475         return (hwq << BLK_MQ_UNIQUE_TAG_BITS) |
487                 (rq->tag & BLK_MQ_UNIQUE_TAG_M    476                 (rq->tag & BLK_MQ_UNIQUE_TAG_MASK);
488 }                                                 477 }
489 EXPORT_SYMBOL(blk_mq_unique_tag);                 478 EXPORT_SYMBOL(blk_mq_unique_tag);
490                                                   479 

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