[PATCH] x86_64: Clean up copy_*_user
[linux-2.6.git] / arch / s390 / mm / cmm.c
1 /*
2  *  arch/s390/mm/cmm.c
3  *
4  *  S390 version
5  *    Copyright (C) 2003 IBM Deutschland Entwicklung GmbH, IBM Corporation
6  *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
7  *
8  *  Collaborative memory management interface.
9  */
10
11 #include <linux/config.h>
12 #include <linux/errno.h>
13 #include <linux/fs.h>
14 #include <linux/init.h>
15 #include <linux/module.h>
16 #include <linux/sched.h>
17 #include <linux/sysctl.h>
18 #include <linux/ctype.h>
19
20 #include <asm/pgalloc.h>
21 #include <asm/uaccess.h>
22
23 static char *sender = "VMRMSVM";
24 module_param(sender, charp, 0400);
25 MODULE_PARM_DESC(sender,
26                  "Guest name that may send SMSG messages (default VMRMSVM)");
27
28 #include "../../../drivers/s390/net/smsgiucv.h"
29
30 #define CMM_NR_PAGES ((PAGE_SIZE / sizeof(unsigned long)) - 2)
31
32 struct cmm_page_array {
33         struct cmm_page_array *next;
34         unsigned long index;
35         unsigned long pages[CMM_NR_PAGES];
36 };
37
38 static long cmm_pages = 0;
39 static long cmm_timed_pages = 0;
40 static volatile long cmm_pages_target = 0;
41 static volatile long cmm_timed_pages_target = 0;
42 static long cmm_timeout_pages = 0;
43 static long cmm_timeout_seconds = 0;
44
45 static struct cmm_page_array *cmm_page_list = 0;
46 static struct cmm_page_array *cmm_timed_page_list = 0;
47
48 static unsigned long cmm_thread_active = 0;
49 static struct work_struct cmm_thread_starter;
50 static wait_queue_head_t cmm_thread_wait;
51 static struct timer_list cmm_timer;
52
53 static void cmm_timer_fn(unsigned long);
54 static void cmm_set_timer(void);
55
56 static long
57 cmm_strtoul(const char *cp, char **endp)
58 {
59         unsigned int base = 10;
60
61         if (*cp == '0') {
62                 base = 8;
63                 cp++;
64                 if ((*cp == 'x' || *cp == 'X') && isxdigit(cp[1])) {
65                         base = 16;
66                         cp++;
67                 }
68         }
69         return simple_strtoul(cp, endp, base);
70 }
71
72 static long
73 cmm_alloc_pages(long pages, long *counter, struct cmm_page_array **list)
74 {
75         struct cmm_page_array *pa;
76         unsigned long page;
77
78         pa = *list;
79         while (pages) {
80                 page = __get_free_page(GFP_NOIO);
81                 if (!page)
82                         break;
83                 if (!pa || pa->index >= CMM_NR_PAGES) {
84                         /* Need a new page for the page list. */
85                         pa = (struct cmm_page_array *)
86                                 __get_free_page(GFP_NOIO);
87                         if (!pa) {
88                                 free_page(page);
89                                 break;
90                         }
91                         pa->next = *list;
92                         pa->index = 0;
93                         *list = pa;
94                 }
95                 diag10(page);
96                 pa->pages[pa->index++] = page;
97                 (*counter)++;
98                 pages--;
99         }
100         return pages;
101 }
102
103 static void
104 cmm_free_pages(long pages, long *counter, struct cmm_page_array **list)
105 {
106         struct cmm_page_array *pa;
107         unsigned long page;
108
109         pa = *list;
110         while (pages) {
111                 if (!pa || pa->index <= 0)
112                         break;
113                 page = pa->pages[--pa->index];
114                 if (pa->index == 0) {
115                         pa = pa->next;
116                         free_page((unsigned long) *list);
117                         *list = pa;
118                 }
119                 free_page(page);
120                 (*counter)--;
121                 pages--;
122         }
123 }
124
125 static int
126 cmm_thread(void *dummy)
127 {
128         int rc;
129
130         daemonize("cmmthread");
131         while (1) {
132                 rc = wait_event_interruptible(cmm_thread_wait,
133                         (cmm_pages != cmm_pages_target ||
134                          cmm_timed_pages != cmm_timed_pages_target));
135                 if (rc == -ERESTARTSYS) {
136                         /* Got kill signal. End thread. */
137                         clear_bit(0, &cmm_thread_active);
138                         cmm_pages_target = cmm_pages;
139                         cmm_timed_pages_target = cmm_timed_pages;
140                         break;
141                 }
142                 if (cmm_pages_target > cmm_pages) {
143                         if (cmm_alloc_pages(1, &cmm_pages, &cmm_page_list))
144                                 cmm_pages_target = cmm_pages;
145                 } else if (cmm_pages_target < cmm_pages) {
146                         cmm_free_pages(1, &cmm_pages, &cmm_page_list);
147                 }
148                 if (cmm_timed_pages_target > cmm_timed_pages) {
149                         if (cmm_alloc_pages(1, &cmm_timed_pages,
150                                            &cmm_timed_page_list))
151                                 cmm_timed_pages_target = cmm_timed_pages;
152                 } else if (cmm_timed_pages_target < cmm_timed_pages) {
153                         cmm_free_pages(1, &cmm_timed_pages,
154                                        &cmm_timed_page_list);
155                 }
156                 if (cmm_timed_pages > 0 && !timer_pending(&cmm_timer))
157                         cmm_set_timer();
158         }
159         return 0;
160 }
161
162 static void
163 cmm_start_thread(void)
164 {
165         kernel_thread(cmm_thread, 0, 0);
166 }
167
168 static void
169 cmm_kick_thread(void)
170 {
171         if (!test_and_set_bit(0, &cmm_thread_active))
172                 schedule_work(&cmm_thread_starter);
173         wake_up(&cmm_thread_wait);
174 }
175
176 static void
177 cmm_set_timer(void)
178 {
179         if (cmm_timed_pages_target <= 0 || cmm_timeout_seconds <= 0) {
180                 if (timer_pending(&cmm_timer))
181                         del_timer(&cmm_timer);
182                 return;
183         }
184         if (timer_pending(&cmm_timer)) {
185                 if (mod_timer(&cmm_timer, jiffies + cmm_timeout_seconds*HZ))
186                         return;
187         }
188         cmm_timer.function = cmm_timer_fn;
189         cmm_timer.data = 0;
190         cmm_timer.expires = jiffies + cmm_timeout_seconds*HZ;
191         add_timer(&cmm_timer);
192 }
193
194 static void
195 cmm_timer_fn(unsigned long ignored)
196 {
197         long pages;
198
199         pages = cmm_timed_pages_target - cmm_timeout_pages;
200         if (pages < 0)
201                 cmm_timed_pages_target = 0;
202         else
203                 cmm_timed_pages_target = pages;
204         cmm_kick_thread();
205         cmm_set_timer();
206 }
207
208 void
209 cmm_set_pages(long pages)
210 {
211         cmm_pages_target = pages;
212         cmm_kick_thread();
213 }
214
215 long
216 cmm_get_pages(void)
217 {
218         return cmm_pages;
219 }
220
221 void
222 cmm_add_timed_pages(long pages)
223 {
224         cmm_timed_pages_target += pages;
225         cmm_kick_thread();
226 }
227
228 long
229 cmm_get_timed_pages(void)
230 {
231         return cmm_timed_pages;
232 }
233
234 void
235 cmm_set_timeout(long pages, long seconds)
236 {
237         cmm_timeout_pages = pages;
238         cmm_timeout_seconds = seconds;
239         cmm_set_timer();
240 }
241
242 static inline int
243 cmm_skip_blanks(char *cp, char **endp)
244 {
245         char *str;
246
247         for (str = cp; *str == ' ' || *str == '\t'; str++);
248         *endp = str;
249         return str != cp;
250 }
251
252 #ifdef CONFIG_CMM_PROC
253 /* These will someday get removed. */
254 #define VM_CMM_PAGES            1111
255 #define VM_CMM_TIMED_PAGES      1112
256 #define VM_CMM_TIMEOUT          1113
257
258 static struct ctl_table cmm_table[];
259
260 static int
261 cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
262                   void *buffer, size_t *lenp, loff_t *ppos)
263 {
264         char buf[16], *p;
265         long pages;
266         int len;
267
268         if (!*lenp || (*ppos && !write)) {
269                 *lenp = 0;
270                 return 0;
271         }
272
273         if (write) {
274                 len = *lenp;
275                 if (copy_from_user(buf, buffer,
276                                    len > sizeof(buf) ? sizeof(buf) : len))
277                         return -EFAULT;
278                 buf[sizeof(buf) - 1] = '\0';
279                 cmm_skip_blanks(buf, &p);
280                 pages = cmm_strtoul(p, &p);
281                 if (ctl == &cmm_table[0])
282                         cmm_set_pages(pages);
283                 else
284                         cmm_add_timed_pages(pages);
285         } else {
286                 if (ctl == &cmm_table[0])
287                         pages = cmm_get_pages();
288                 else
289                         pages = cmm_get_timed_pages();
290                 len = sprintf(buf, "%ld\n", pages);
291                 if (len > *lenp)
292                         len = *lenp;
293                 if (copy_to_user(buffer, buf, len))
294                         return -EFAULT;
295         }
296         *lenp = len;
297         *ppos += len;
298         return 0;
299 }
300
301 static int
302 cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
303                     void *buffer, size_t *lenp, loff_t *ppos)
304 {
305         char buf[64], *p;
306         long pages, seconds;
307         int len;
308
309         if (!*lenp || (*ppos && !write)) {
310                 *lenp = 0;
311                 return 0;
312         }
313
314         if (write) {
315                 len = *lenp;
316                 if (copy_from_user(buf, buffer,
317                                    len > sizeof(buf) ? sizeof(buf) : len))
318                         return -EFAULT;
319                 buf[sizeof(buf) - 1] = '\0';
320                 cmm_skip_blanks(buf, &p);
321                 pages = cmm_strtoul(p, &p);
322                 cmm_skip_blanks(p, &p);
323                 seconds = cmm_strtoul(p, &p);
324                 cmm_set_timeout(pages, seconds);
325         } else {
326                 len = sprintf(buf, "%ld %ld\n",
327                               cmm_timeout_pages, cmm_timeout_seconds);
328                 if (len > *lenp)
329                         len = *lenp;
330                 if (copy_to_user(buffer, buf, len))
331                         return -EFAULT;
332         }
333         *lenp = len;
334         *ppos += len;
335         return 0;
336 }
337
338 static struct ctl_table cmm_table[] = {
339         {
340                 .ctl_name       = VM_CMM_PAGES,
341                 .procname       = "cmm_pages",
342                 .mode           = 0600,
343                 .proc_handler   = &cmm_pages_handler,
344         },
345         {
346                 .ctl_name       = VM_CMM_TIMED_PAGES,
347                 .procname       = "cmm_timed_pages",
348                 .mode           = 0600,
349                 .proc_handler   = &cmm_pages_handler,
350         },
351         {
352                 .ctl_name       = VM_CMM_TIMEOUT,
353                 .procname       = "cmm_timeout",
354                 .mode           = 0600,
355                 .proc_handler   = &cmm_timeout_handler,
356         },
357         { .ctl_name = 0 }
358 };
359
360 static struct ctl_table cmm_dir_table[] = {
361         {
362                 .ctl_name       = CTL_VM,
363                 .procname       = "vm",
364                 .maxlen         = 0,
365                 .mode           = 0555,
366                 .child          = cmm_table,
367         },
368         { .ctl_name = 0 }
369 };
370 #endif
371
372 #ifdef CONFIG_CMM_IUCV
373 #define SMSG_PREFIX "CMM"
374 static void
375 cmm_smsg_target(char *from, char *msg)
376 {
377         long pages, seconds;
378
379         if (strlen(sender) > 0 && strcmp(from, sender) != 0)
380                 return;
381         if (!cmm_skip_blanks(msg + strlen(SMSG_PREFIX), &msg))
382                 return;
383         if (strncmp(msg, "SHRINK", 6) == 0) {
384                 if (!cmm_skip_blanks(msg + 6, &msg))
385                         return;
386                 pages = cmm_strtoul(msg, &msg);
387                 cmm_skip_blanks(msg, &msg);
388                 if (*msg == '\0')
389                         cmm_set_pages(pages);
390         } else if (strncmp(msg, "RELEASE", 7) == 0) {
391                 if (!cmm_skip_blanks(msg + 7, &msg))
392                         return;
393                 pages = cmm_strtoul(msg, &msg);
394                 cmm_skip_blanks(msg, &msg);
395                 if (*msg == '\0')
396                         cmm_add_timed_pages(pages);
397         } else if (strncmp(msg, "REUSE", 5) == 0) {
398                 if (!cmm_skip_blanks(msg + 5, &msg))
399                         return;
400                 pages = cmm_strtoul(msg, &msg);
401                 if (!cmm_skip_blanks(msg, &msg))
402                         return;
403                 seconds = cmm_strtoul(msg, &msg);
404                 cmm_skip_blanks(msg, &msg);
405                 if (*msg == '\0')
406                         cmm_set_timeout(pages, seconds);
407         }
408 }
409 #endif
410
411 struct ctl_table_header *cmm_sysctl_header;
412
413 static int
414 cmm_init (void)
415 {
416 #ifdef CONFIG_CMM_PROC
417         cmm_sysctl_header = register_sysctl_table(cmm_dir_table, 1);
418 #endif
419 #ifdef CONFIG_CMM_IUCV
420         smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);
421 #endif
422         INIT_WORK(&cmm_thread_starter, (void *) cmm_start_thread, 0);
423         init_waitqueue_head(&cmm_thread_wait);
424         init_timer(&cmm_timer);
425         return 0;
426 }
427
428 static void
429 cmm_exit(void)
430 {
431         cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);
432         cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);
433 #ifdef CONFIG_CMM_PROC
434         unregister_sysctl_table(cmm_sysctl_header);
435 #endif
436 #ifdef CONFIG_CMM_IUCV
437         smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);
438 #endif
439 }
440
441 module_init(cmm_init);
442 module_exit(cmm_exit);
443
444 EXPORT_SYMBOL(cmm_set_pages);
445 EXPORT_SYMBOL(cmm_get_pages);
446 EXPORT_SYMBOL(cmm_add_timed_pages);
447 EXPORT_SYMBOL(cmm_get_timed_pages);
448 EXPORT_SYMBOL(cmm_set_timeout);
449
450 MODULE_LICENSE("GPL");