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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-4.18.20)


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

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