tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/*******************************************************************************
2 * This file contains the iSCSI Login Thread and Thread Queue functions.
3 *
4 * (c) Copyright 2007-2013 Datera, Inc.
5 *
6 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 ******************************************************************************/
18
19#include <linux/kthread.h>
20#include <linux/list.h>
21#include <linux/bitmap.h>
22
23#include <target/iscsi/iscsi_target_core.h>
24#include "iscsi_target_tq.h"
25#include "iscsi_target.h"
26
27static LIST_HEAD(inactive_ts_list);
28static DEFINE_SPINLOCK(inactive_ts_lock);
29static DEFINE_SPINLOCK(ts_bitmap_lock);
30
31static void iscsi_add_ts_to_inactive_list(struct iscsi_thread_set *ts)
32{
33 if (!list_empty(&ts->ts_list)) {
34 WARN_ON(1);
35 return;
36 }
37 spin_lock(&inactive_ts_lock);
38 list_add_tail(&ts->ts_list, &inactive_ts_list);
39 iscsit_global->inactive_ts++;
40 spin_unlock(&inactive_ts_lock);
41}
42
43static struct iscsi_thread_set *iscsi_get_ts_from_inactive_list(void)
44{
45 struct iscsi_thread_set *ts;
46
47 spin_lock(&inactive_ts_lock);
48 if (list_empty(&inactive_ts_list)) {
49 spin_unlock(&inactive_ts_lock);
50 return NULL;
51 }
52
53 ts = list_first_entry(&inactive_ts_list, struct iscsi_thread_set, ts_list);
54
55 list_del_init(&ts->ts_list);
56 iscsit_global->inactive_ts--;
57 spin_unlock(&inactive_ts_lock);
58
59 return ts;
60}
61
62int iscsi_allocate_thread_sets(u32 thread_pair_count)
63{
64 int allocated_thread_pair_count = 0, i, thread_id;
65 struct iscsi_thread_set *ts = NULL;
66
67 for (i = 0; i < thread_pair_count; i++) {
68 ts = kzalloc(sizeof(struct iscsi_thread_set), GFP_KERNEL);
69 if (!ts) {
70 pr_err("Unable to allocate memory for"
71 " thread set.\n");
72 return allocated_thread_pair_count;
73 }
74 /*
75 * Locate the next available regision in the thread_set_bitmap
76 */
77 spin_lock(&ts_bitmap_lock);
78 thread_id = bitmap_find_free_region(iscsit_global->ts_bitmap,
79 iscsit_global->ts_bitmap_count, get_order(1));
80 spin_unlock(&ts_bitmap_lock);
81 if (thread_id < 0) {
82 pr_err("bitmap_find_free_region() failed for"
83 " thread_set_bitmap\n");
84 kfree(ts);
85 return allocated_thread_pair_count;
86 }
87
88 ts->thread_id = thread_id;
89 ts->status = ISCSI_THREAD_SET_FREE;
90 INIT_LIST_HEAD(&ts->ts_list);
91 spin_lock_init(&ts->ts_state_lock);
92 init_completion(&ts->rx_restart_comp);
93 init_completion(&ts->tx_restart_comp);
94 init_completion(&ts->rx_start_comp);
95 init_completion(&ts->tx_start_comp);
96 sema_init(&ts->ts_activate_sem, 0);
97
98 ts->create_threads = 1;
99 ts->tx_thread = kthread_run(iscsi_target_tx_thread, ts, "%s",
100 ISCSI_TX_THREAD_NAME);
101 if (IS_ERR(ts->tx_thread)) {
102 dump_stack();
103 pr_err("Unable to start iscsi_target_tx_thread\n");
104 break;
105 }
106
107 ts->rx_thread = kthread_run(iscsi_target_rx_thread, ts, "%s",
108 ISCSI_RX_THREAD_NAME);
109 if (IS_ERR(ts->rx_thread)) {
110 kthread_stop(ts->tx_thread);
111 pr_err("Unable to start iscsi_target_rx_thread\n");
112 break;
113 }
114 ts->create_threads = 0;
115
116 iscsi_add_ts_to_inactive_list(ts);
117 allocated_thread_pair_count++;
118 }
119
120 pr_debug("Spawned %d thread set(s) (%d total threads).\n",
121 allocated_thread_pair_count, allocated_thread_pair_count * 2);
122 return allocated_thread_pair_count;
123}
124
125static void iscsi_deallocate_thread_one(struct iscsi_thread_set *ts)
126{
127 spin_lock_bh(&ts->ts_state_lock);
128 ts->status = ISCSI_THREAD_SET_DIE;
129
130 if (ts->rx_thread) {
131 complete(&ts->rx_start_comp);
132 spin_unlock_bh(&ts->ts_state_lock);
133 kthread_stop(ts->rx_thread);
134 spin_lock_bh(&ts->ts_state_lock);
135 }
136 if (ts->tx_thread) {
137 complete(&ts->tx_start_comp);
138 spin_unlock_bh(&ts->ts_state_lock);
139 kthread_stop(ts->tx_thread);
140 spin_lock_bh(&ts->ts_state_lock);
141 }
142 spin_unlock_bh(&ts->ts_state_lock);
143 /*
144 * Release this thread_id in the thread_set_bitmap
145 */
146 spin_lock(&ts_bitmap_lock);
147 bitmap_release_region(iscsit_global->ts_bitmap,
148 ts->thread_id, get_order(1));
149 spin_unlock(&ts_bitmap_lock);
150
151 kfree(ts);
152}
153
154void iscsi_deallocate_thread_sets(void)
155{
156 struct iscsi_thread_set *ts = NULL;
157 u32 released_count = 0;
158
159 while ((ts = iscsi_get_ts_from_inactive_list())) {
160
161 iscsi_deallocate_thread_one(ts);
162 released_count++;
163 }
164
165 if (released_count)
166 pr_debug("Stopped %d thread set(s) (%d total threads)."
167 "\n", released_count, released_count * 2);
168}
169
170static void iscsi_deallocate_extra_thread_sets(void)
171{
172 u32 orig_count, released_count = 0;
173 struct iscsi_thread_set *ts = NULL;
174
175 orig_count = TARGET_THREAD_SET_COUNT;
176
177 while ((iscsit_global->inactive_ts + 1) > orig_count) {
178 ts = iscsi_get_ts_from_inactive_list();
179 if (!ts)
180 break;
181
182 iscsi_deallocate_thread_one(ts);
183 released_count++;
184 }
185
186 if (released_count)
187 pr_debug("Stopped %d thread set(s) (%d total threads)."
188 "\n", released_count, released_count * 2);
189}
190
191void iscsi_activate_thread_set(struct iscsi_conn *conn, struct iscsi_thread_set *ts)
192{
193 spin_lock_bh(&ts->ts_state_lock);
194 conn->thread_set = ts;
195 ts->conn = conn;
196 ts->status = ISCSI_THREAD_SET_ACTIVE;
197 spin_unlock_bh(&ts->ts_state_lock);
198
199 complete(&ts->rx_start_comp);
200 complete(&ts->tx_start_comp);
201
202 down(&ts->ts_activate_sem);
203}
204
205struct iscsi_thread_set *iscsi_get_thread_set(void)
206{
207 struct iscsi_thread_set *ts;
208
209get_set:
210 ts = iscsi_get_ts_from_inactive_list();
211 if (!ts) {
212 iscsi_allocate_thread_sets(1);
213 goto get_set;
214 }
215
216 ts->delay_inactive = 1;
217 ts->signal_sent = 0;
218 ts->thread_count = 2;
219 init_completion(&ts->rx_restart_comp);
220 init_completion(&ts->tx_restart_comp);
221 sema_init(&ts->ts_activate_sem, 0);
222
223 return ts;
224}
225
226void iscsi_set_thread_clear(struct iscsi_conn *conn, u8 thread_clear)
227{
228 struct iscsi_thread_set *ts = NULL;
229
230 if (!conn->thread_set) {
231 pr_err("struct iscsi_conn->thread_set is NULL\n");
232 return;
233 }
234 ts = conn->thread_set;
235
236 spin_lock_bh(&ts->ts_state_lock);
237 ts->thread_clear &= ~thread_clear;
238
239 if ((thread_clear & ISCSI_CLEAR_RX_THREAD) &&
240 (ts->blocked_threads & ISCSI_BLOCK_RX_THREAD))
241 complete(&ts->rx_restart_comp);
242 else if ((thread_clear & ISCSI_CLEAR_TX_THREAD) &&
243 (ts->blocked_threads & ISCSI_BLOCK_TX_THREAD))
244 complete(&ts->tx_restart_comp);
245 spin_unlock_bh(&ts->ts_state_lock);
246}
247
248void iscsi_set_thread_set_signal(struct iscsi_conn *conn, u8 signal_sent)
249{
250 struct iscsi_thread_set *ts = NULL;
251
252 if (!conn->thread_set) {
253 pr_err("struct iscsi_conn->thread_set is NULL\n");
254 return;
255 }
256 ts = conn->thread_set;
257
258 spin_lock_bh(&ts->ts_state_lock);
259 ts->signal_sent |= signal_sent;
260 spin_unlock_bh(&ts->ts_state_lock);
261}
262
263int iscsi_release_thread_set(struct iscsi_conn *conn)
264{
265 int thread_called = 0;
266 struct iscsi_thread_set *ts = NULL;
267
268 if (!conn || !conn->thread_set) {
269 pr_err("connection or thread set pointer is NULL\n");
270 BUG();
271 }
272 ts = conn->thread_set;
273
274 spin_lock_bh(&ts->ts_state_lock);
275 ts->status = ISCSI_THREAD_SET_RESET;
276
277 if (!strncmp(current->comm, ISCSI_RX_THREAD_NAME,
278 strlen(ISCSI_RX_THREAD_NAME)))
279 thread_called = ISCSI_RX_THREAD;
280 else if (!strncmp(current->comm, ISCSI_TX_THREAD_NAME,
281 strlen(ISCSI_TX_THREAD_NAME)))
282 thread_called = ISCSI_TX_THREAD;
283
284 if (ts->rx_thread && (thread_called == ISCSI_TX_THREAD) &&
285 (ts->thread_clear & ISCSI_CLEAR_RX_THREAD)) {
286
287 if (!(ts->signal_sent & ISCSI_SIGNAL_RX_THREAD)) {
288 send_sig(SIGINT, ts->rx_thread, 1);
289 ts->signal_sent |= ISCSI_SIGNAL_RX_THREAD;
290 }
291 ts->blocked_threads |= ISCSI_BLOCK_RX_THREAD;
292 spin_unlock_bh(&ts->ts_state_lock);
293 wait_for_completion(&ts->rx_restart_comp);
294 spin_lock_bh(&ts->ts_state_lock);
295 ts->blocked_threads &= ~ISCSI_BLOCK_RX_THREAD;
296 }
297 if (ts->tx_thread && (thread_called == ISCSI_RX_THREAD) &&
298 (ts->thread_clear & ISCSI_CLEAR_TX_THREAD)) {
299
300 if (!(ts->signal_sent & ISCSI_SIGNAL_TX_THREAD)) {
301 send_sig(SIGINT, ts->tx_thread, 1);
302 ts->signal_sent |= ISCSI_SIGNAL_TX_THREAD;
303 }
304 ts->blocked_threads |= ISCSI_BLOCK_TX_THREAD;
305 spin_unlock_bh(&ts->ts_state_lock);
306 wait_for_completion(&ts->tx_restart_comp);
307 spin_lock_bh(&ts->ts_state_lock);
308 ts->blocked_threads &= ~ISCSI_BLOCK_TX_THREAD;
309 }
310
311 ts->conn = NULL;
312 ts->status = ISCSI_THREAD_SET_FREE;
313 spin_unlock_bh(&ts->ts_state_lock);
314
315 return 0;
316}
317
318int iscsi_thread_set_force_reinstatement(struct iscsi_conn *conn)
319{
320 struct iscsi_thread_set *ts;
321
322 if (!conn->thread_set)
323 return -1;
324 ts = conn->thread_set;
325
326 spin_lock_bh(&ts->ts_state_lock);
327 if (ts->status != ISCSI_THREAD_SET_ACTIVE) {
328 spin_unlock_bh(&ts->ts_state_lock);
329 return -1;
330 }
331
332 if (ts->tx_thread && (!(ts->signal_sent & ISCSI_SIGNAL_TX_THREAD))) {
333 send_sig(SIGINT, ts->tx_thread, 1);
334 ts->signal_sent |= ISCSI_SIGNAL_TX_THREAD;
335 }
336 if (ts->rx_thread && (!(ts->signal_sent & ISCSI_SIGNAL_RX_THREAD))) {
337 send_sig(SIGINT, ts->rx_thread, 1);
338 ts->signal_sent |= ISCSI_SIGNAL_RX_THREAD;
339 }
340 spin_unlock_bh(&ts->ts_state_lock);
341
342 return 0;
343}
344
345static void iscsi_check_to_add_additional_sets(void)
346{
347 int thread_sets_add;
348
349 spin_lock(&inactive_ts_lock);
350 thread_sets_add = iscsit_global->inactive_ts;
351 spin_unlock(&inactive_ts_lock);
352 if (thread_sets_add == 1)
353 iscsi_allocate_thread_sets(1);
354}
355
356static int iscsi_signal_thread_pre_handler(struct iscsi_thread_set *ts)
357{
358 spin_lock_bh(&ts->ts_state_lock);
359 if (ts->status == ISCSI_THREAD_SET_DIE || kthread_should_stop() ||
360 signal_pending(current)) {
361 spin_unlock_bh(&ts->ts_state_lock);
362 return -1;
363 }
364 spin_unlock_bh(&ts->ts_state_lock);
365
366 return 0;
367}
368
369struct iscsi_conn *iscsi_rx_thread_pre_handler(struct iscsi_thread_set *ts)
370{
371 int ret;
372
373 spin_lock_bh(&ts->ts_state_lock);
374 if (ts->create_threads) {
375 spin_unlock_bh(&ts->ts_state_lock);
376 goto sleep;
377 }
378
379 if (ts->status != ISCSI_THREAD_SET_DIE)
380 flush_signals(current);
381
382 if (ts->delay_inactive && (--ts->thread_count == 0)) {
383 spin_unlock_bh(&ts->ts_state_lock);
384
385 if (!iscsit_global->in_shutdown)
386 iscsi_deallocate_extra_thread_sets();
387
388 iscsi_add_ts_to_inactive_list(ts);
389 spin_lock_bh(&ts->ts_state_lock);
390 }
391
392 if ((ts->status == ISCSI_THREAD_SET_RESET) &&
393 (ts->thread_clear & ISCSI_CLEAR_RX_THREAD))
394 complete(&ts->rx_restart_comp);
395
396 ts->thread_clear &= ~ISCSI_CLEAR_RX_THREAD;
397 spin_unlock_bh(&ts->ts_state_lock);
398sleep:
399 ret = wait_for_completion_interruptible(&ts->rx_start_comp);
400 if (ret != 0)
401 return NULL;
402
403 if (iscsi_signal_thread_pre_handler(ts) < 0)
404 return NULL;
405
406 iscsi_check_to_add_additional_sets();
407
408 spin_lock_bh(&ts->ts_state_lock);
409 if (!ts->conn) {
410 pr_err("struct iscsi_thread_set->conn is NULL for"
411 " RX thread_id: %s/%d\n", current->comm, current->pid);
412 spin_unlock_bh(&ts->ts_state_lock);
413 return NULL;
414 }
415 ts->thread_clear |= ISCSI_CLEAR_RX_THREAD;
416 spin_unlock_bh(&ts->ts_state_lock);
417
418 up(&ts->ts_activate_sem);
419
420 return ts->conn;
421}
422
423struct iscsi_conn *iscsi_tx_thread_pre_handler(struct iscsi_thread_set *ts)
424{
425 int ret;
426
427 spin_lock_bh(&ts->ts_state_lock);
428 if (ts->create_threads) {
429 spin_unlock_bh(&ts->ts_state_lock);
430 goto sleep;
431 }
432
433 if (ts->status != ISCSI_THREAD_SET_DIE)
434 flush_signals(current);
435
436 if (ts->delay_inactive && (--ts->thread_count == 0)) {
437 spin_unlock_bh(&ts->ts_state_lock);
438
439 if (!iscsit_global->in_shutdown)
440 iscsi_deallocate_extra_thread_sets();
441
442 iscsi_add_ts_to_inactive_list(ts);
443 spin_lock_bh(&ts->ts_state_lock);
444 }
445 if ((ts->status == ISCSI_THREAD_SET_RESET) &&
446 (ts->thread_clear & ISCSI_CLEAR_TX_THREAD))
447 complete(&ts->tx_restart_comp);
448
449 ts->thread_clear &= ~ISCSI_CLEAR_TX_THREAD;
450 spin_unlock_bh(&ts->ts_state_lock);
451sleep:
452 ret = wait_for_completion_interruptible(&ts->tx_start_comp);
453 if (ret != 0)
454 return NULL;
455
456 if (iscsi_signal_thread_pre_handler(ts) < 0)
457 return NULL;
458
459 iscsi_check_to_add_additional_sets();
460
461 spin_lock_bh(&ts->ts_state_lock);
462 if (!ts->conn) {
463 pr_err("struct iscsi_thread_set->conn is NULL for"
464 " TX thread_id: %s/%d\n", current->comm, current->pid);
465 spin_unlock_bh(&ts->ts_state_lock);
466 return NULL;
467 }
468 ts->thread_clear |= ISCSI_CLEAR_TX_THREAD;
469 spin_unlock_bh(&ts->ts_state_lock);
470
471 up(&ts->ts_activate_sem);
472
473 return ts->conn;
474}
475
476int iscsi_thread_set_init(void)
477{
478 int size;
479
480 iscsit_global->ts_bitmap_count = ISCSI_TS_BITMAP_BITS;
481
482 size = BITS_TO_LONGS(iscsit_global->ts_bitmap_count) * sizeof(long);
483 iscsit_global->ts_bitmap = kzalloc(size, GFP_KERNEL);
484 if (!iscsit_global->ts_bitmap) {
485 pr_err("Unable to allocate iscsit_global->ts_bitmap\n");
486 return -ENOMEM;
487 }
488
489 return 0;
490}
491
492void iscsi_thread_set_free(void)
493{
494 kfree(iscsit_global->ts_bitmap);
495}