[S390] dasd: fix reference counting in display method for proc/dasd/devices
[safe/jmp/linux-2.6] / drivers / s390 / block / dasd_proc.c
1 /*
2  * File...........: linux/drivers/s390/block/dasd_proc.c
3  * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
4  *                  Horst Hummel <Horst.Hummel@de.ibm.com>
5  *                  Carsten Otte <Cotte@de.ibm.com>
6  *                  Martin Schwidefsky <schwidefsky@de.ibm.com>
7  * Bugreports.to..: <Linux390@de.ibm.com>
8  * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2002
9  *
10  * /proc interface for the dasd driver.
11  *
12  */
13
14 #include <linux/ctype.h>
15 #include <linux/seq_file.h>
16 #include <linux/vmalloc.h>
17 #include <linux/proc_fs.h>
18
19 #include <asm/debug.h>
20 #include <asm/uaccess.h>
21
22 /* This is ugly... */
23 #define PRINTK_HEADER "dasd_proc:"
24
25 #include "dasd_int.h"
26
27 static struct proc_dir_entry *dasd_proc_root_entry = NULL;
28 static struct proc_dir_entry *dasd_devices_entry = NULL;
29 static struct proc_dir_entry *dasd_statistics_entry = NULL;
30
31 #ifdef CONFIG_DASD_PROFILE
32 static char *
33 dasd_get_user_string(const char __user *user_buf, size_t user_len)
34 {
35         char *buffer;
36
37         buffer = kmalloc(user_len + 1, GFP_KERNEL);
38         if (buffer == NULL)
39                 return ERR_PTR(-ENOMEM);
40         if (copy_from_user(buffer, user_buf, user_len) != 0) {
41                 kfree(buffer);
42                 return ERR_PTR(-EFAULT);
43         }
44         /* got the string, now strip linefeed. */
45         if (buffer[user_len - 1] == '\n')
46                 buffer[user_len - 1] = 0;
47         else
48                 buffer[user_len] = 0;
49         return buffer;
50 }
51 #endif /* CONFIG_DASD_PROFILE */
52
53 static int
54 dasd_devices_show(struct seq_file *m, void *v)
55 {
56         struct dasd_device *device;
57         struct dasd_block *block;
58         char *substr;
59
60         device = dasd_device_from_devindex((unsigned long) v - 1);
61         if (IS_ERR(device))
62                 return 0;
63         if (device->block)
64                 block = device->block;
65         else {
66                 dasd_put_device(device);
67                 return 0;
68         }
69         /* Print device number. */
70         seq_printf(m, "%s", device->cdev->dev.bus_id);
71         /* Print discipline string. */
72         if (device != NULL && device->discipline != NULL)
73                 seq_printf(m, "(%s)", device->discipline->name);
74         else
75                 seq_printf(m, "(none)");
76         /* Print kdev. */
77         if (block->gdp)
78                 seq_printf(m, " at (%3d:%6d)",
79                            block->gdp->major, block->gdp->first_minor);
80         else
81                 seq_printf(m, "  at (???:??????)");
82         /* Print device name. */
83         if (block->gdp)
84                 seq_printf(m, " is %-8s", block->gdp->disk_name);
85         else
86                 seq_printf(m, " is ????????");
87         /* Print devices features. */
88         substr = (device->features & DASD_FEATURE_READONLY) ? "(ro)" : " ";
89         seq_printf(m, "%4s: ", substr);
90         /* Print device status information. */
91         switch ((device != NULL) ? device->state : -1) {
92         case -1:
93                 seq_printf(m, "unknown");
94                 break;
95         case DASD_STATE_NEW:
96                 seq_printf(m, "new");
97                 break;
98         case DASD_STATE_KNOWN:
99                 seq_printf(m, "detected");
100                 break;
101         case DASD_STATE_BASIC:
102                 seq_printf(m, "basic");
103                 break;
104         case DASD_STATE_UNFMT:
105                 seq_printf(m, "unformatted");
106                 break;
107         case DASD_STATE_READY:
108         case DASD_STATE_ONLINE:
109                 seq_printf(m, "active ");
110                 if (dasd_check_blocksize(block->bp_block))
111                         seq_printf(m, "n/f       ");
112                 else
113                         seq_printf(m,
114                                    "at blocksize: %d, %ld blocks, %ld MB",
115                                    block->bp_block, block->blocks,
116                                    ((block->bp_block >> 9) *
117                                     block->blocks) >> 11);
118                 break;
119         default:
120                 seq_printf(m, "no stat");
121                 break;
122         }
123         dasd_put_device(device);
124         if (dasd_probeonly)
125                 seq_printf(m, "(probeonly)");
126         seq_printf(m, "\n");
127         return 0;
128 }
129
130 static void *dasd_devices_start(struct seq_file *m, loff_t *pos)
131 {
132         if (*pos >= dasd_max_devindex)
133                 return NULL;
134         return (void *)((unsigned long) *pos + 1);
135 }
136
137 static void *dasd_devices_next(struct seq_file *m, void *v, loff_t *pos)
138 {
139         ++*pos;
140         return dasd_devices_start(m, pos);
141 }
142
143 static void dasd_devices_stop(struct seq_file *m, void *v)
144 {
145 }
146
147 static const struct seq_operations dasd_devices_seq_ops = {
148         .start          = dasd_devices_start,
149         .next           = dasd_devices_next,
150         .stop           = dasd_devices_stop,
151         .show           = dasd_devices_show,
152 };
153
154 static int dasd_devices_open(struct inode *inode, struct file *file)
155 {
156         return seq_open(file, &dasd_devices_seq_ops);
157 }
158
159 static const struct file_operations dasd_devices_file_ops = {
160         .open           = dasd_devices_open,
161         .read           = seq_read,
162         .llseek         = seq_lseek,
163         .release        = seq_release,
164 };
165
166 static int
167 dasd_calc_metrics(char *page, char **start, off_t off,
168                   int count, int *eof, int len)
169 {
170         len = (len > off) ? len - off : 0;
171         if (len > count)
172                 len = count;
173         if (len < count)
174                 *eof = 1;
175         *start = page + off;
176         return len;
177 }
178
179 #ifdef CONFIG_DASD_PROFILE
180 static char *
181 dasd_statistics_array(char *str, unsigned int *array, int shift)
182 {
183         int i;
184
185         for (i = 0; i < 32; i++) {
186                 str += sprintf(str, "%7d ", array[i] >> shift);
187                 if (i == 15)
188                         str += sprintf(str, "\n");
189         }
190         str += sprintf(str,"\n");
191         return str;
192 }
193 #endif /* CONFIG_DASD_PROFILE */
194
195 static int
196 dasd_statistics_read(char *page, char **start, off_t off,
197                      int count, int *eof, void *data)
198 {
199         unsigned long len;
200 #ifdef CONFIG_DASD_PROFILE
201         struct dasd_profile_info_t *prof;
202         char *str;
203         int shift;
204
205         /* check for active profiling */
206         if (dasd_profile_level == DASD_PROFILE_OFF) {
207                 len = sprintf(page, "Statistics are off - they might be "
208                                     "switched on using 'echo set on > "
209                                     "/proc/dasd/statistics'\n");
210                 return dasd_calc_metrics(page, start, off, count, eof, len);
211         }
212
213         prof = &dasd_global_profile;
214         /* prevent couter 'overflow' on output */
215         for (shift = 0; (prof->dasd_io_reqs >> shift) > 9999999; shift++);
216
217         str = page;
218         str += sprintf(str, "%d dasd I/O requests\n", prof->dasd_io_reqs);
219         str += sprintf(str, "with %d sectors(512B each)\n",
220                        prof->dasd_io_sects);
221         str += sprintf(str,
222                        "   __<4    ___8    __16    __32    __64    _128 "
223                        "   _256    _512    __1k    __2k    __4k    __8k "
224                        "   _16k    _32k    _64k    128k\n");
225         str += sprintf(str,
226                        "   _256    _512    __1M    __2M    __4M    __8M "
227                        "   _16M    _32M    _64M    128M    256M    512M "
228                        "   __1G    __2G    __4G " "   _>4G\n");
229
230         str += sprintf(str, "Histogram of sizes (512B secs)\n");
231         str = dasd_statistics_array(str, prof->dasd_io_secs, shift);
232         str += sprintf(str, "Histogram of I/O times (microseconds)\n");
233         str = dasd_statistics_array(str, prof->dasd_io_times, shift);
234         str += sprintf(str, "Histogram of I/O times per sector\n");
235         str = dasd_statistics_array(str, prof->dasd_io_timps, shift);
236         str += sprintf(str, "Histogram of I/O time till ssch\n");
237         str = dasd_statistics_array(str, prof->dasd_io_time1, shift);
238         str += sprintf(str, "Histogram of I/O time between ssch and irq\n");
239         str = dasd_statistics_array(str, prof->dasd_io_time2, shift);
240         str += sprintf(str, "Histogram of I/O time between ssch "
241                             "and irq per sector\n");
242         str = dasd_statistics_array(str, prof->dasd_io_time2ps, shift);
243         str += sprintf(str, "Histogram of I/O time between irq and end\n");
244         str = dasd_statistics_array(str, prof->dasd_io_time3, shift);
245         str += sprintf(str, "# of req in chanq at enqueuing (1..32) \n");
246         str = dasd_statistics_array(str, prof->dasd_io_nr_req, shift);
247         len = str - page;
248 #else
249         len = sprintf(page, "Statistics are not activated in this kernel\n");
250 #endif
251         return dasd_calc_metrics(page, start, off, count, eof, len);
252 }
253
254 static int
255 dasd_statistics_write(struct file *file, const char __user *user_buf,
256                       unsigned long user_len, void *data)
257 {
258 #ifdef CONFIG_DASD_PROFILE
259         char *buffer, *str;
260
261         if (user_len > 65536)
262                 user_len = 65536;
263         buffer = dasd_get_user_string(user_buf, user_len);
264         if (IS_ERR(buffer))
265                 return PTR_ERR(buffer);
266         MESSAGE_LOG(KERN_INFO, "/proc/dasd/statictics: '%s'", buffer);
267
268         /* check for valid verbs */
269         for (str = buffer; isspace(*str); str++);
270         if (strncmp(str, "set", 3) == 0 && isspace(str[3])) {
271                 /* 'set xxx' was given */
272                 for (str = str + 4; isspace(*str); str++);
273                 if (strcmp(str, "on") == 0) {
274                         /* switch on statistics profiling */
275                         dasd_profile_level = DASD_PROFILE_ON;
276                         MESSAGE(KERN_INFO, "%s", "Statistics switched on");
277                 } else if (strcmp(str, "off") == 0) {
278                         /* switch off and reset statistics profiling */
279                         memset(&dasd_global_profile,
280                                0, sizeof (struct dasd_profile_info_t));
281                         dasd_profile_level = DASD_PROFILE_OFF;
282                         MESSAGE(KERN_INFO, "%s", "Statistics switched off");
283                 } else
284                         goto out_error;
285         } else if (strncmp(str, "reset", 5) == 0) {
286                 /* reset the statistics */
287                 memset(&dasd_global_profile, 0,
288                        sizeof (struct dasd_profile_info_t));
289                 MESSAGE(KERN_INFO, "%s", "Statistics reset");
290         } else
291                 goto out_error;
292         kfree(buffer);
293         return user_len;
294 out_error:
295         MESSAGE(KERN_WARNING, "%s",
296                 "/proc/dasd/statistics: only 'set on', 'set off' "
297                 "and 'reset' are supported verbs");
298         kfree(buffer);
299         return -EINVAL;
300 #else
301         MESSAGE(KERN_WARNING, "%s",
302                 "/proc/dasd/statistics: is not activated in this kernel");
303         return user_len;
304 #endif                          /* CONFIG_DASD_PROFILE */
305 }
306
307 /*
308  * Create dasd proc-fs entries.
309  * In case creation failed, cleanup and return -ENOENT.
310  */
311 int
312 dasd_proc_init(void)
313 {
314         dasd_proc_root_entry = proc_mkdir("dasd", &proc_root);
315         if (!dasd_proc_root_entry)
316                 goto out_nodasd;
317         dasd_proc_root_entry->owner = THIS_MODULE;
318         dasd_devices_entry = create_proc_entry("devices",
319                                                S_IFREG | S_IRUGO | S_IWUSR,
320                                                dasd_proc_root_entry);
321         if (!dasd_devices_entry)
322                 goto out_nodevices;
323         dasd_devices_entry->proc_fops = &dasd_devices_file_ops;
324         dasd_devices_entry->owner = THIS_MODULE;
325         dasd_statistics_entry = create_proc_entry("statistics",
326                                                   S_IFREG | S_IRUGO | S_IWUSR,
327                                                   dasd_proc_root_entry);
328         if (!dasd_statistics_entry)
329                 goto out_nostatistics;
330         dasd_statistics_entry->read_proc = dasd_statistics_read;
331         dasd_statistics_entry->write_proc = dasd_statistics_write;
332         dasd_statistics_entry->owner = THIS_MODULE;
333         return 0;
334
335  out_nostatistics:
336         remove_proc_entry("devices", dasd_proc_root_entry);
337  out_nodevices:
338         remove_proc_entry("dasd", &proc_root);
339  out_nodasd:
340         return -ENOENT;
341 }
342
343 void
344 dasd_proc_exit(void)
345 {
346         remove_proc_entry("devices", dasd_proc_root_entry);
347         remove_proc_entry("statistics", dasd_proc_root_entry);
348         remove_proc_entry("dasd", &proc_root);
349 }