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10#include <linux/errno.h>
11#include <linux/fs.h>
12#include <linux/init.h>
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/gfp.h>
16#include <linux/sched.h>
17#include <linux/sysctl.h>
18#include <linux/ctype.h>
19#include <linux/swap.h>
20#include <linux/kthread.h>
21#include <linux/oom.h>
22#include <linux/uaccess.h>
23
24#include <asm/diag.h>
25
26#ifdef CONFIG_CMM_IUCV
27static char *cmm_default_sender = "VMRMSVM";
28#endif
29static char *sender;
30module_param(sender, charp, 0400);
31MODULE_PARM_DESC(sender,
32 "Guest name that may send SMSG messages (default VMRMSVM)");
33
34#include "../../../drivers/s390/net/smsgiucv.h"
35
36#define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
37
38struct cmm_page_array {
39 struct cmm_page_array *next;
40 unsigned long index;
41 unsigned long pages[CMM_NR_PAGES];
42};
43
44static long cmm_pages;
45static long cmm_timed_pages;
46static volatile long cmm_pages_target;
47static volatile long cmm_timed_pages_target;
48static long cmm_timeout_pages;
49static long cmm_timeout_seconds;
50
51static struct cmm_page_array *cmm_page_list;
52static struct cmm_page_array *cmm_timed_page_list;
53static DEFINE_SPINLOCK(cmm_lock);
54
55static struct task_struct *cmm_thread_ptr;
56static DECLARE_WAIT_QUEUE_HEAD(cmm_thread_wait);
57
58static void cmm_timer_fn(struct timer_list *);
59static void cmm_set_timer(void);
60static DEFINE_TIMER(cmm_timer, cmm_timer_fn);
61
62static long cmm_alloc_pages(long nr, long *counter,
63 struct cmm_page_array **list)
64{
65 struct cmm_page_array *pa, *npa;
66 unsigned long addr;
67
68 while (nr) {
69 addr = __get_free_page(GFP_NOIO);
70 if (!addr)
71 break;
72 spin_lock(&cmm_lock);
73 pa = *list;
74 if (!pa || pa->index >= CMM_NR_PAGES) {
75
76 spin_unlock(&cmm_lock);
77 npa = (struct cmm_page_array *)
78 __get_free_page(GFP_NOIO);
79 if (!npa) {
80 free_page(addr);
81 break;
82 }
83 spin_lock(&cmm_lock);
84 pa = *list;
85 if (!pa || pa->index >= CMM_NR_PAGES) {
86 npa->next = pa;
87 npa->index = 0;
88 pa = npa;
89 *list = pa;
90 } else
91 free_page((unsigned long) npa);
92 }
93 diag10_range(addr >> PAGE_SHIFT, 1);
94 pa->pages[pa->index++] = addr;
95 (*counter)++;
96 spin_unlock(&cmm_lock);
97 nr--;
98 }
99 return nr;
100}
101
102static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
103{
104 struct cmm_page_array *pa;
105 unsigned long addr;
106
107 spin_lock(&cmm_lock);
108 pa = *list;
109 while (nr) {
110 if (!pa || pa->index <= 0)
111 break;
112 addr = pa->pages[--pa->index];
113 if (pa->index == 0) {
114 pa = pa->next;
115 free_page((unsigned long) *list);
116 *list = pa;
117 }
118 free_page(addr);
119 (*counter)--;
120 nr--;
121 }
122 spin_unlock(&cmm_lock);
123 return nr;
124}
125
126static int cmm_oom_notify(struct notifier_block *self,
127 unsigned long dummy, void *parm)
128{
129 unsigned long *freed = parm;
130 long nr = 256;
131
132 nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
133 if (nr > 0)
134 nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
135 cmm_pages_target = cmm_pages;
136 cmm_timed_pages_target = cmm_timed_pages;
137 *freed += 256 - nr;
138 return NOTIFY_OK;
139}
140
141static struct notifier_block cmm_oom_nb = {
142 .notifier_call = cmm_oom_notify,
143};
144
145static int cmm_thread(void *dummy)
146{
147 int rc;
148
149 while (1) {
150 rc = wait_event_interruptible(cmm_thread_wait,
151 cmm_pages != cmm_pages_target ||
152 cmm_timed_pages != cmm_timed_pages_target ||
153 kthread_should_stop());
154 if (kthread_should_stop() || rc == -ERESTARTSYS) {
155 cmm_pages_target = cmm_pages;
156 cmm_timed_pages_target = cmm_timed_pages;
157 break;
158 }
159 if (cmm_pages_target > cmm_pages) {
160 if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
161 cmm_pages_target = cmm_pages;
162 } else if (cmm_pages_target < cmm_pages) {
163 cmm_free_pages(1, &cmm_pages, &cmm_page_list);
164 }
165 if (cmm_timed_pages_target > cmm_timed_pages) {
166 if (cmm_alloc_pages(1, &cmm_timed_pages,
167 &cmm_timed_page_list))
168 cmm_timed_pages_target = cmm_timed_pages;
169 } else if (cmm_timed_pages_target < cmm_timed_pages) {
170 cmm_free_pages(1, &cmm_timed_pages,
171 &cmm_timed_page_list);
172 }
173 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
174 cmm_set_timer();
175 }
176 return 0;
177}
178
179static void cmm_kick_thread(void)
180{
181 wake_up(&cmm_thread_wait);
182}
183
184static void cmm_set_timer(void)
185{
186 if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
187 if (timer_pending(&cmm_timer))
188 del_timer(&cmm_timer);
189 return;
190 }
191 mod_timer(&cmm_timer, jiffies + msecs_to_jiffies(cmm_timeout_seconds * MSEC_PER_SEC));
192}
193
194static void cmm_timer_fn(struct timer_list *unused)
195{
196 long nr;
197
198 nr = cmm_timed_pages_target - cmm_timeout_pages;
199 if (nr < 0)
200 cmm_timed_pages_target = 0;
201 else
202 cmm_timed_pages_target = nr;
203 cmm_kick_thread();
204 cmm_set_timer();
205}
206
207static void cmm_set_pages(long nr)
208{
209 cmm_pages_target = nr;
210 cmm_kick_thread();
211}
212
213static long cmm_get_pages(void)
214{
215 return cmm_pages;
216}
217
218static void cmm_add_timed_pages(long nr)
219{
220 cmm_timed_pages_target += nr;
221 cmm_kick_thread();
222}
223
224static long cmm_get_timed_pages(void)
225{
226 return cmm_timed_pages;
227}
228
229static void cmm_set_timeout(long nr, long seconds)
230{
231 cmm_timeout_pages = nr;
232 cmm_timeout_seconds = seconds;
233 cmm_set_timer();
234}
235
236static int cmm_skip_blanks(char *cp, char **endp)
237{
238 char *str;
239
240 for (str = cp; *str == ' ' || *str == '\t'; str++)
241 ;
242 *endp = str;
243 return str != cp;
244}
245
246static int cmm_pages_handler(struct ctl_table *ctl, int write,
247 void *buffer, size_t *lenp, loff_t *ppos)
248{
249 long nr = cmm_get_pages();
250 struct ctl_table ctl_entry = {
251 .procname = ctl->procname,
252 .data = &nr,
253 .maxlen = sizeof(long),
254 };
255 int rc;
256
257 rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
258 if (rc < 0 || !write)
259 return rc;
260
261 cmm_set_pages(nr);
262 return 0;
263}
264
265static int cmm_timed_pages_handler(struct ctl_table *ctl, int write,
266 void *buffer, size_t *lenp,
267 loff_t *ppos)
268{
269 long nr = cmm_get_timed_pages();
270 struct ctl_table ctl_entry = {
271 .procname = ctl->procname,
272 .data = &nr,
273 .maxlen = sizeof(long),
274 };
275 int rc;
276
277 rc = proc_doulongvec_minmax(&ctl_entry, write, buffer, lenp, ppos);
278 if (rc < 0 || !write)
279 return rc;
280
281 cmm_add_timed_pages(nr);
282 return 0;
283}
284
285static int cmm_timeout_handler(struct ctl_table *ctl, int write,
286 void *buffer, size_t *lenp, loff_t *ppos)
287{
288 char buf[64], *p;
289 long nr, seconds;
290 unsigned int len;
291
292 if (!*lenp || (*ppos && !write)) {
293 *lenp = 0;
294 return 0;
295 }
296
297 if (write) {
298 len = min(*lenp, sizeof(buf));
299 memcpy(buf, buffer, len);
300 buf[len - 1] = '\0';
301 cmm_skip_blanks(buf, &p);
302 nr = simple_strtoul(p, &p, 0);
303 cmm_skip_blanks(p, &p);
304 seconds = simple_strtoul(p, &p, 0);
305 cmm_set_timeout(nr, seconds);
306 *ppos += *lenp;
307 } else {
308 len = sprintf(buf, "%ld %ld\n",
309 cmm_timeout_pages, cmm_timeout_seconds);
310 if (len > *lenp)
311 len = *lenp;
312 memcpy(buffer, buf, len);
313 *lenp = len;
314 *ppos += len;
315 }
316 return 0;
317}
318
319static struct ctl_table cmm_table[] = {
320 {
321 .procname = "cmm_pages",
322 .mode = 0644,
323 .proc_handler = cmm_pages_handler,
324 },
325 {
326 .procname = "cmm_timed_pages",
327 .mode = 0644,
328 .proc_handler = cmm_timed_pages_handler,
329 },
330 {
331 .procname = "cmm_timeout",
332 .mode = 0644,
333 .proc_handler = cmm_timeout_handler,
334 },
335 { }
336};
337
338static struct ctl_table cmm_dir_table[] = {
339 {
340 .procname = "vm",
341 .maxlen = 0,
342 .mode = 0555,
343 .child = cmm_table,
344 },
345 { }
346};
347
348#ifdef CONFIG_CMM_IUCV
349#define SMSG_PREFIX "CMM"
350static void cmm_smsg_target(const char *from, char *msg)
351{
352 long nr, seconds;
353
354 if (strlen(sender) > 0 && strcmp(from, sender) != 0)
355 return;
356 if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
357 return;
358 if (strncmp(msg, "SHRINK", 6) == 0) {
359 if (!cmm_skip_blanks(msg + 6, &msg))
360 return;
361 nr = simple_strtoul(msg, &msg, 0);
362 cmm_skip_blanks(msg, &msg);
363 if (*msg == '\0')
364 cmm_set_pages(nr);
365 } else if (strncmp(msg, "RELEASE", 7) == 0) {
366 if (!cmm_skip_blanks(msg + 7, &msg))
367 return;
368 nr = simple_strtoul(msg, &msg, 0);
369 cmm_skip_blanks(msg, &msg);
370 if (*msg == '\0')
371 cmm_add_timed_pages(nr);
372 } else if (strncmp(msg, "REUSE", 5) == 0) {
373 if (!cmm_skip_blanks(msg + 5, &msg))
374 return;
375 nr = simple_strtoul(msg, &msg, 0);
376 if (!cmm_skip_blanks(msg, &msg))
377 return;
378 seconds = simple_strtoul(msg, &msg, 0);
379 cmm_skip_blanks(msg, &msg);
380 if (*msg == '\0')
381 cmm_set_timeout(nr, seconds);
382 }
383}
384#endif
385
386static struct ctl_table_header *cmm_sysctl_header;
387
388static int __init cmm_init(void)
389{
390 int rc = -ENOMEM;
391
392 cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
393 if (!cmm_sysctl_header)
394 goto out_sysctl;
395#ifdef CONFIG_CMM_IUCV
396
397 if (sender) {
398 int len = strlen(sender);
399 while (len--)
400 sender[len] = toupper(sender[len]);
401 } else {
402 sender = cmm_default_sender;
403 }
404
405 rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
406 if (rc < 0)
407 goto out_smsg;
408#endif
409 rc = register_oom_notifier(&cmm_oom_nb);
410 if (rc < 0)
411 goto out_oom_notify;
412 cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");
413 if (!IS_ERR(cmm_thread_ptr))
414 return 0;
415
416 rc = PTR_ERR(cmm_thread_ptr);
417 unregister_oom_notifier(&cmm_oom_nb);
418out_oom_notify:
419#ifdef CONFIG_CMM_IUCV
420 smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
421out_smsg:
422#endif
423 unregister_sysctl_table(cmm_sysctl_header);
424out_sysctl:
425 del_timer_sync(&cmm_timer);
426 return rc;
427}
428module_init(cmm_init);
429
430static void __exit cmm_exit(void)
431{
432 unregister_sysctl_table(cmm_sysctl_header);
433#ifdef CONFIG_CMM_IUCV
434 smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
435#endif
436 unregister_oom_notifier(&cmm_oom_nb);
437 kthread_stop(cmm_thread_ptr);
438 del_timer_sync(&cmm_timer);
439 cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
440 cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
441}
442module_exit(cmm_exit);
443
444MODULE_LICENSE("GPL");
445
