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20c64468 SW |
1 | /* |
2 | * Character device driver for extended error reporting. | |
3 | * | |
4 | * Copyright (C) 2005 IBM Corporation | |
5 | * extended error reporting for DASD ECKD devices | |
6 | * Author(s): Stefan Weinhuber <wein@de.ibm.com> | |
7 | */ | |
8 | ||
ca99dab0 | 9 | #define KMSG_COMPONENT "dasd-eckd" |
fc19f381 | 10 | |
20c64468 SW |
11 | #include <linux/init.h> |
12 | #include <linux/fs.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/miscdevice.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/moduleparam.h> | |
17 | #include <linux/device.h> | |
18 | #include <linux/poll.h> | |
3006d7c6 | 19 | #include <linux/mutex.h> |
986837ba | 20 | #include <linux/smp_lock.h> |
0983e568 | 21 | #include <linux/err.h> |
5a0e3ad6 | 22 | #include <linux/slab.h> |
20c64468 SW |
23 | |
24 | #include <asm/uaccess.h> | |
20c64468 SW |
25 | #include <asm/atomic.h> |
26 | #include <asm/ebcdic.h> | |
27 | ||
28 | #include "dasd_int.h" | |
29 | #include "dasd_eckd.h" | |
30 | ||
31 | #ifdef PRINTK_HEADER | |
32 | #undef PRINTK_HEADER | |
33 | #endif /* PRINTK_HEADER */ | |
34 | #define PRINTK_HEADER "dasd(eer):" | |
35 | ||
36 | /* | |
37 | * SECTION: the internal buffer | |
38 | */ | |
39 | ||
40 | /* | |
41 | * The internal buffer is meant to store obaque blobs of data, so it does | |
42 | * not know of higher level concepts like triggers. | |
43 | * It consists of a number of pages that are used as a ringbuffer. Each data | |
44 | * blob is stored in a simple record that consists of an integer, which | |
45 | * contains the size of the following data, and the data bytes themselfes. | |
46 | * | |
47 | * To allow for multiple independent readers we create one internal buffer | |
48 | * each time the device is opened and destroy the buffer when the file is | |
49 | * closed again. The number of pages used for this buffer is determined by | |
50 | * the module parmeter eer_pages. | |
51 | * | |
52 | * One record can be written to a buffer by using the functions | |
53 | * - dasd_eer_start_record (one time per record to write the size to the | |
54 | * buffer and reserve the space for the data) | |
55 | * - dasd_eer_write_buffer (one or more times per record to write the data) | |
56 | * The data can be written in several steps but you will have to compute | |
57 | * the total size up front for the invocation of dasd_eer_start_record. | |
58 | * If the ringbuffer is full, dasd_eer_start_record will remove the required | |
59 | * number of old records. | |
60 | * | |
61 | * A record is typically read in two steps, first read the integer that | |
62 | * specifies the size of the following data, then read the data. | |
63 | * Both can be done by | |
64 | * - dasd_eer_read_buffer | |
65 | * | |
66 | * For all mentioned functions you need to get the bufferlock first and keep | |
67 | * it until a complete record is written or read. | |
68 | * | |
69 | * All information necessary to keep track of an internal buffer is kept in | |
70 | * a struct eerbuffer. The buffer specific to a file pointer is strored in | |
71 | * the private_data field of that file. To be able to write data to all | |
72 | * existing buffers, each buffer is also added to the bufferlist. | |
73 | * If the user does not want to read a complete record in one go, we have to | |
74 | * keep track of the rest of the record. residual stores the number of bytes | |
75 | * that are still to deliver. If the rest of the record is invalidated between | |
76 | * two reads then residual will be set to -1 so that the next read will fail. | |
77 | * All entries in the eerbuffer structure are protected with the bufferlock. | |
78 | * To avoid races between writing to a buffer on the one side and creating | |
79 | * and destroying buffers on the other side, the bufferlock must also be used | |
80 | * to protect the bufferlist. | |
81 | */ | |
82 | ||
83 | static int eer_pages = 5; | |
84 | module_param(eer_pages, int, S_IRUGO|S_IWUSR); | |
85 | ||
86 | struct eerbuffer { | |
87 | struct list_head list; | |
88 | char **buffer; | |
89 | int buffersize; | |
90 | int buffer_page_count; | |
91 | int head; | |
92 | int tail; | |
93 | int residual; | |
94 | }; | |
95 | ||
96 | static LIST_HEAD(bufferlist); | |
34af946a | 97 | static DEFINE_SPINLOCK(bufferlock); |
20c64468 SW |
98 | static DECLARE_WAIT_QUEUE_HEAD(dasd_eer_read_wait_queue); |
99 | ||
100 | /* | |
101 | * How many free bytes are available on the buffer. | |
102 | * Needs to be called with bufferlock held. | |
103 | */ | |
104 | static int dasd_eer_get_free_bytes(struct eerbuffer *eerb) | |
105 | { | |
106 | if (eerb->head < eerb->tail) | |
107 | return eerb->tail - eerb->head - 1; | |
108 | return eerb->buffersize - eerb->head + eerb->tail -1; | |
109 | } | |
110 | ||
111 | /* | |
112 | * How many bytes of buffer space are used. | |
113 | * Needs to be called with bufferlock held. | |
114 | */ | |
115 | static int dasd_eer_get_filled_bytes(struct eerbuffer *eerb) | |
116 | { | |
117 | ||
118 | if (eerb->head >= eerb->tail) | |
119 | return eerb->head - eerb->tail; | |
120 | return eerb->buffersize - eerb->tail + eerb->head; | |
121 | } | |
122 | ||
123 | /* | |
124 | * The dasd_eer_write_buffer function just copies count bytes of data | |
125 | * to the buffer. Make sure to call dasd_eer_start_record first, to | |
126 | * make sure that enough free space is available. | |
127 | * Needs to be called with bufferlock held. | |
128 | */ | |
129 | static void dasd_eer_write_buffer(struct eerbuffer *eerb, | |
130 | char *data, int count) | |
131 | { | |
132 | ||
133 | unsigned long headindex,localhead; | |
134 | unsigned long rest, len; | |
135 | char *nextdata; | |
136 | ||
137 | nextdata = data; | |
138 | rest = count; | |
139 | while (rest > 0) { | |
140 | headindex = eerb->head / PAGE_SIZE; | |
141 | localhead = eerb->head % PAGE_SIZE; | |
142 | len = min(rest, PAGE_SIZE - localhead); | |
143 | memcpy(eerb->buffer[headindex]+localhead, nextdata, len); | |
144 | nextdata += len; | |
145 | rest -= len; | |
146 | eerb->head += len; | |
147 | if (eerb->head == eerb->buffersize) | |
148 | eerb->head = 0; /* wrap around */ | |
149 | BUG_ON(eerb->head > eerb->buffersize); | |
150 | } | |
151 | } | |
152 | ||
153 | /* | |
154 | * Needs to be called with bufferlock held. | |
155 | */ | |
156 | static int dasd_eer_read_buffer(struct eerbuffer *eerb, char *data, int count) | |
157 | { | |
158 | ||
159 | unsigned long tailindex,localtail; | |
160 | unsigned long rest, len, finalcount; | |
161 | char *nextdata; | |
162 | ||
163 | finalcount = min(count, dasd_eer_get_filled_bytes(eerb)); | |
164 | nextdata = data; | |
165 | rest = finalcount; | |
166 | while (rest > 0) { | |
167 | tailindex = eerb->tail / PAGE_SIZE; | |
168 | localtail = eerb->tail % PAGE_SIZE; | |
169 | len = min(rest, PAGE_SIZE - localtail); | |
170 | memcpy(nextdata, eerb->buffer[tailindex] + localtail, len); | |
171 | nextdata += len; | |
172 | rest -= len; | |
173 | eerb->tail += len; | |
174 | if (eerb->tail == eerb->buffersize) | |
175 | eerb->tail = 0; /* wrap around */ | |
176 | BUG_ON(eerb->tail > eerb->buffersize); | |
177 | } | |
178 | return finalcount; | |
179 | } | |
180 | ||
181 | /* | |
182 | * Whenever you want to write a blob of data to the internal buffer you | |
183 | * have to start by using this function first. It will write the number | |
184 | * of bytes that will be written to the buffer. If necessary it will remove | |
185 | * old records to make room for the new one. | |
186 | * Needs to be called with bufferlock held. | |
187 | */ | |
188 | static int dasd_eer_start_record(struct eerbuffer *eerb, int count) | |
189 | { | |
190 | int tailcount; | |
191 | ||
192 | if (count + sizeof(count) > eerb->buffersize) | |
193 | return -ENOMEM; | |
194 | while (dasd_eer_get_free_bytes(eerb) < count + sizeof(count)) { | |
195 | if (eerb->residual > 0) { | |
196 | eerb->tail += eerb->residual; | |
197 | if (eerb->tail >= eerb->buffersize) | |
198 | eerb->tail -= eerb->buffersize; | |
199 | eerb->residual = -1; | |
200 | } | |
201 | dasd_eer_read_buffer(eerb, (char *) &tailcount, | |
202 | sizeof(tailcount)); | |
203 | eerb->tail += tailcount; | |
204 | if (eerb->tail >= eerb->buffersize) | |
205 | eerb->tail -= eerb->buffersize; | |
206 | } | |
207 | dasd_eer_write_buffer(eerb, (char*) &count, sizeof(count)); | |
208 | ||
209 | return 0; | |
210 | }; | |
211 | ||
212 | /* | |
213 | * Release pages that are not used anymore. | |
214 | */ | |
215 | static void dasd_eer_free_buffer_pages(char **buf, int no_pages) | |
216 | { | |
217 | int i; | |
218 | ||
219 | for (i = 0; i < no_pages; i++) | |
220 | free_page((unsigned long) buf[i]); | |
221 | } | |
222 | ||
223 | /* | |
224 | * Allocate a new set of memory pages. | |
225 | */ | |
226 | static int dasd_eer_allocate_buffer_pages(char **buf, int no_pages) | |
227 | { | |
228 | int i; | |
229 | ||
230 | for (i = 0; i < no_pages; i++) { | |
231 | buf[i] = (char *) get_zeroed_page(GFP_KERNEL); | |
232 | if (!buf[i]) { | |
233 | dasd_eer_free_buffer_pages(buf, i); | |
234 | return -ENOMEM; | |
235 | } | |
236 | } | |
237 | return 0; | |
238 | } | |
239 | ||
240 | /* | |
241 | * SECTION: The extended error reporting functionality | |
242 | */ | |
243 | ||
244 | /* | |
245 | * When a DASD device driver wants to report an error, it calls the | |
246 | * function dasd_eer_write and gives the respective trigger ID as | |
247 | * parameter. Currently there are four kinds of triggers: | |
248 | * | |
249 | * DASD_EER_FATALERROR: all kinds of unrecoverable I/O problems | |
250 | * DASD_EER_PPRCSUSPEND: PPRC was suspended | |
251 | * DASD_EER_NOPATH: There is no path to the device left. | |
252 | * DASD_EER_STATECHANGE: The state of the device has changed. | |
253 | * | |
254 | * For the first three triggers all required information can be supplied by | |
255 | * the caller. For these triggers a record is written by the function | |
256 | * dasd_eer_write_standard_trigger. | |
257 | * | |
258 | * The DASD_EER_STATECHANGE trigger is special since a sense subsystem | |
259 | * status ccw need to be executed to gather the necessary sense data first. | |
260 | * The dasd_eer_snss function will queue the SNSS request and the request | |
261 | * callback will then call dasd_eer_write with the DASD_EER_STATCHANGE | |
262 | * trigger. | |
263 | * | |
264 | * To avoid memory allocations at runtime, the necessary memory is allocated | |
265 | * when the extended error reporting is enabled for a device (by | |
266 | * dasd_eer_probe). There is one sense subsystem status request for each | |
267 | * eer enabled DASD device. The presence of the cqr in device->eer_cqr | |
268 | * indicates that eer is enable for the device. The use of the snss request | |
269 | * is protected by the DASD_FLAG_EER_IN_USE bit. When this flag indicates | |
270 | * that the cqr is currently in use, dasd_eer_snss cannot start a second | |
271 | * request but sets the DASD_FLAG_EER_SNSS flag instead. The callback of | |
272 | * the SNSS request will check the bit and call dasd_eer_snss again. | |
273 | */ | |
274 | ||
275 | #define SNSS_DATA_SIZE 44 | |
276 | ||
277 | #define DASD_EER_BUSID_SIZE 10 | |
278 | struct dasd_eer_header { | |
279 | __u32 total_size; | |
280 | __u32 trigger; | |
281 | __u64 tv_sec; | |
282 | __u64 tv_usec; | |
283 | char busid[DASD_EER_BUSID_SIZE]; | |
774fc4ef | 284 | } __attribute__ ((packed)); |
20c64468 SW |
285 | |
286 | /* | |
287 | * The following function can be used for those triggers that have | |
288 | * all necessary data available when the function is called. | |
289 | * If the parameter cqr is not NULL, the chain of requests will be searched | |
290 | * for valid sense data, and all valid sense data sets will be added to | |
291 | * the triggers data. | |
292 | */ | |
293 | static void dasd_eer_write_standard_trigger(struct dasd_device *device, | |
294 | struct dasd_ccw_req *cqr, | |
295 | int trigger) | |
296 | { | |
297 | struct dasd_ccw_req *temp_cqr; | |
298 | int data_size; | |
299 | struct timeval tv; | |
300 | struct dasd_eer_header header; | |
301 | unsigned long flags; | |
302 | struct eerbuffer *eerb; | |
f3eb5384 | 303 | char *sense; |
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304 | |
305 | /* go through cqr chain and count the valid sense data sets */ | |
306 | data_size = 0; | |
307 | for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) | |
f3eb5384 | 308 | if (dasd_get_sense(&temp_cqr->irb)) |
20c64468 SW |
309 | data_size += 32; |
310 | ||
311 | header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ | |
312 | header.trigger = trigger; | |
313 | do_gettimeofday(&tv); | |
314 | header.tv_sec = tv.tv_sec; | |
315 | header.tv_usec = tv.tv_usec; | |
2a0217d5 KS |
316 | strncpy(header.busid, dev_name(&device->cdev->dev), |
317 | DASD_EER_BUSID_SIZE); | |
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318 | |
319 | spin_lock_irqsave(&bufferlock, flags); | |
320 | list_for_each_entry(eerb, &bufferlist, list) { | |
321 | dasd_eer_start_record(eerb, header.total_size); | |
322 | dasd_eer_write_buffer(eerb, (char *) &header, sizeof(header)); | |
f3eb5384 SW |
323 | for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) { |
324 | sense = dasd_get_sense(&temp_cqr->irb); | |
325 | if (sense) | |
326 | dasd_eer_write_buffer(eerb, sense, 32); | |
327 | } | |
20c64468 SW |
328 | dasd_eer_write_buffer(eerb, "EOR", 4); |
329 | } | |
330 | spin_unlock_irqrestore(&bufferlock, flags); | |
331 | wake_up_interruptible(&dasd_eer_read_wait_queue); | |
332 | } | |
333 | ||
334 | /* | |
335 | * This function writes a DASD_EER_STATECHANGE trigger. | |
336 | */ | |
337 | static void dasd_eer_write_snss_trigger(struct dasd_device *device, | |
338 | struct dasd_ccw_req *cqr, | |
339 | int trigger) | |
340 | { | |
341 | int data_size; | |
342 | int snss_rc; | |
343 | struct timeval tv; | |
344 | struct dasd_eer_header header; | |
345 | unsigned long flags; | |
346 | struct eerbuffer *eerb; | |
347 | ||
8e09f215 | 348 | snss_rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO; |
20c64468 SW |
349 | if (snss_rc) |
350 | data_size = 0; | |
351 | else | |
352 | data_size = SNSS_DATA_SIZE; | |
353 | ||
354 | header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ | |
355 | header.trigger = DASD_EER_STATECHANGE; | |
356 | do_gettimeofday(&tv); | |
357 | header.tv_sec = tv.tv_sec; | |
358 | header.tv_usec = tv.tv_usec; | |
2a0217d5 KS |
359 | strncpy(header.busid, dev_name(&device->cdev->dev), |
360 | DASD_EER_BUSID_SIZE); | |
20c64468 SW |
361 | |
362 | spin_lock_irqsave(&bufferlock, flags); | |
363 | list_for_each_entry(eerb, &bufferlist, list) { | |
364 | dasd_eer_start_record(eerb, header.total_size); | |
365 | dasd_eer_write_buffer(eerb, (char *) &header , sizeof(header)); | |
366 | if (!snss_rc) | |
367 | dasd_eer_write_buffer(eerb, cqr->data, SNSS_DATA_SIZE); | |
368 | dasd_eer_write_buffer(eerb, "EOR", 4); | |
369 | } | |
370 | spin_unlock_irqrestore(&bufferlock, flags); | |
371 | wake_up_interruptible(&dasd_eer_read_wait_queue); | |
372 | } | |
373 | ||
374 | /* | |
375 | * This function is called for all triggers. It calls the appropriate | |
376 | * function that writes the actual trigger records. | |
377 | */ | |
378 | void dasd_eer_write(struct dasd_device *device, struct dasd_ccw_req *cqr, | |
379 | unsigned int id) | |
380 | { | |
381 | if (!device->eer_cqr) | |
382 | return; | |
383 | switch (id) { | |
384 | case DASD_EER_FATALERROR: | |
385 | case DASD_EER_PPRCSUSPEND: | |
386 | dasd_eer_write_standard_trigger(device, cqr, id); | |
387 | break; | |
388 | case DASD_EER_NOPATH: | |
389 | dasd_eer_write_standard_trigger(device, NULL, id); | |
390 | break; | |
391 | case DASD_EER_STATECHANGE: | |
392 | dasd_eer_write_snss_trigger(device, cqr, id); | |
393 | break; | |
394 | default: /* unknown trigger, so we write it without any sense data */ | |
395 | dasd_eer_write_standard_trigger(device, NULL, id); | |
396 | break; | |
397 | } | |
398 | } | |
399 | EXPORT_SYMBOL(dasd_eer_write); | |
400 | ||
401 | /* | |
402 | * Start a sense subsystem status request. | |
403 | * Needs to be called with the device held. | |
404 | */ | |
405 | void dasd_eer_snss(struct dasd_device *device) | |
406 | { | |
407 | struct dasd_ccw_req *cqr; | |
408 | ||
409 | cqr = device->eer_cqr; | |
410 | if (!cqr) /* Device not eer enabled. */ | |
411 | return; | |
412 | if (test_and_set_bit(DASD_FLAG_EER_IN_USE, &device->flags)) { | |
413 | /* Sense subsystem status request in use. */ | |
414 | set_bit(DASD_FLAG_EER_SNSS, &device->flags); | |
415 | return; | |
416 | } | |
8e09f215 | 417 | /* cdev is already locked, can't use dasd_add_request_head */ |
20c64468 SW |
418 | clear_bit(DASD_FLAG_EER_SNSS, &device->flags); |
419 | cqr->status = DASD_CQR_QUEUED; | |
8e09f215 SW |
420 | list_add(&cqr->devlist, &device->ccw_queue); |
421 | dasd_schedule_device_bh(device); | |
20c64468 SW |
422 | } |
423 | ||
424 | /* | |
425 | * Callback function for use with sense subsystem status request. | |
426 | */ | |
427 | static void dasd_eer_snss_cb(struct dasd_ccw_req *cqr, void *data) | |
428 | { | |
8e09f215 | 429 | struct dasd_device *device = cqr->startdev; |
20c64468 SW |
430 | unsigned long flags; |
431 | ||
432 | dasd_eer_write(device, cqr, DASD_EER_STATECHANGE); | |
433 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); | |
434 | if (device->eer_cqr == cqr) { | |
435 | clear_bit(DASD_FLAG_EER_IN_USE, &device->flags); | |
436 | if (test_bit(DASD_FLAG_EER_SNSS, &device->flags)) | |
437 | /* Another SNSS has been requested in the meantime. */ | |
438 | dasd_eer_snss(device); | |
439 | cqr = NULL; | |
440 | } | |
441 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); | |
442 | if (cqr) | |
443 | /* | |
444 | * Extended error recovery has been switched off while | |
445 | * the SNSS request was running. It could even have | |
446 | * been switched off and on again in which case there | |
447 | * is a new ccw in device->eer_cqr. Free the "old" | |
448 | * snss request now. | |
449 | */ | |
450 | dasd_kfree_request(cqr, device); | |
451 | } | |
452 | ||
453 | /* | |
454 | * Enable error reporting on a given device. | |
455 | */ | |
456 | int dasd_eer_enable(struct dasd_device *device) | |
457 | { | |
458 | struct dasd_ccw_req *cqr; | |
459 | unsigned long flags; | |
f3eb5384 | 460 | struct ccw1 *ccw; |
20c64468 SW |
461 | |
462 | if (device->eer_cqr) | |
463 | return 0; | |
464 | ||
465 | if (!device->discipline || strcmp(device->discipline->name, "ECKD")) | |
466 | return -EPERM; /* FIXME: -EMEDIUMTYPE ? */ | |
467 | ||
68b781fe | 468 | cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* SNSS */, |
20c64468 | 469 | SNSS_DATA_SIZE, device); |
0983e568 | 470 | if (IS_ERR(cqr)) |
20c64468 SW |
471 | return -ENOMEM; |
472 | ||
8e09f215 | 473 | cqr->startdev = device; |
20c64468 SW |
474 | cqr->retries = 255; |
475 | cqr->expires = 10 * HZ; | |
046f3e82 | 476 | clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags); |
20c64468 | 477 | |
f3eb5384 SW |
478 | ccw = cqr->cpaddr; |
479 | ccw->cmd_code = DASD_ECKD_CCW_SNSS; | |
480 | ccw->count = SNSS_DATA_SIZE; | |
481 | ccw->flags = 0; | |
482 | ccw->cda = (__u32)(addr_t) cqr->data; | |
20c64468 SW |
483 | |
484 | cqr->buildclk = get_clock(); | |
485 | cqr->status = DASD_CQR_FILLED; | |
486 | cqr->callback = dasd_eer_snss_cb; | |
487 | ||
488 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); | |
489 | if (!device->eer_cqr) { | |
490 | device->eer_cqr = cqr; | |
491 | cqr = NULL; | |
492 | } | |
493 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); | |
494 | if (cqr) | |
495 | dasd_kfree_request(cqr, device); | |
496 | return 0; | |
497 | } | |
498 | ||
499 | /* | |
500 | * Disable error reporting on a given device. | |
501 | */ | |
502 | void dasd_eer_disable(struct dasd_device *device) | |
503 | { | |
504 | struct dasd_ccw_req *cqr; | |
505 | unsigned long flags; | |
506 | int in_use; | |
507 | ||
508 | if (!device->eer_cqr) | |
509 | return; | |
510 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); | |
511 | cqr = device->eer_cqr; | |
512 | device->eer_cqr = NULL; | |
513 | clear_bit(DASD_FLAG_EER_SNSS, &device->flags); | |
514 | in_use = test_and_clear_bit(DASD_FLAG_EER_IN_USE, &device->flags); | |
515 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); | |
516 | if (cqr && !in_use) | |
517 | dasd_kfree_request(cqr, device); | |
518 | } | |
519 | ||
520 | /* | |
521 | * SECTION: the device operations | |
522 | */ | |
523 | ||
524 | /* | |
525 | * On the one side we need a lock to access our internal buffer, on the | |
526 | * other side a copy_to_user can sleep. So we need to copy the data we have | |
527 | * to transfer in a readbuffer, which is protected by the readbuffer_mutex. | |
528 | */ | |
529 | static char readbuffer[PAGE_SIZE]; | |
3006d7c6 | 530 | static DEFINE_MUTEX(readbuffer_mutex); |
20c64468 SW |
531 | |
532 | static int dasd_eer_open(struct inode *inp, struct file *filp) | |
533 | { | |
534 | struct eerbuffer *eerb; | |
535 | unsigned long flags; | |
536 | ||
537 | eerb = kzalloc(sizeof(struct eerbuffer), GFP_KERNEL); | |
f45a43d8 SW |
538 | if (!eerb) |
539 | return -ENOMEM; | |
20c64468 SW |
540 | eerb->buffer_page_count = eer_pages; |
541 | if (eerb->buffer_page_count < 1 || | |
542 | eerb->buffer_page_count > INT_MAX / PAGE_SIZE) { | |
543 | kfree(eerb); | |
fc19f381 | 544 | DBF_EVENT(DBF_WARNING, "can't open device since module " |
025dfdaf FS |
545 | "parameter eer_pages is smaller than 1 or" |
546 | " bigger than %d", (int)(INT_MAX / PAGE_SIZE)); | |
20c64468 SW |
547 | return -EINVAL; |
548 | } | |
549 | eerb->buffersize = eerb->buffer_page_count * PAGE_SIZE; | |
550 | eerb->buffer = kmalloc(eerb->buffer_page_count * sizeof(char *), | |
551 | GFP_KERNEL); | |
552 | if (!eerb->buffer) { | |
553 | kfree(eerb); | |
554 | return -ENOMEM; | |
555 | } | |
556 | if (dasd_eer_allocate_buffer_pages(eerb->buffer, | |
557 | eerb->buffer_page_count)) { | |
558 | kfree(eerb->buffer); | |
559 | kfree(eerb); | |
560 | return -ENOMEM; | |
561 | } | |
562 | filp->private_data = eerb; | |
563 | spin_lock_irqsave(&bufferlock, flags); | |
564 | list_add(&eerb->list, &bufferlist); | |
565 | spin_unlock_irqrestore(&bufferlock, flags); | |
566 | ||
567 | return nonseekable_open(inp,filp); | |
568 | } | |
569 | ||
570 | static int dasd_eer_close(struct inode *inp, struct file *filp) | |
571 | { | |
572 | struct eerbuffer *eerb; | |
573 | unsigned long flags; | |
574 | ||
575 | eerb = (struct eerbuffer *) filp->private_data; | |
576 | spin_lock_irqsave(&bufferlock, flags); | |
577 | list_del(&eerb->list); | |
578 | spin_unlock_irqrestore(&bufferlock, flags); | |
579 | dasd_eer_free_buffer_pages(eerb->buffer, eerb->buffer_page_count); | |
580 | kfree(eerb->buffer); | |
581 | kfree(eerb); | |
582 | ||
583 | return 0; | |
584 | } | |
585 | ||
586 | static ssize_t dasd_eer_read(struct file *filp, char __user *buf, | |
587 | size_t count, loff_t *ppos) | |
588 | { | |
589 | int tc,rc; | |
590 | int tailcount,effective_count; | |
591 | unsigned long flags; | |
592 | struct eerbuffer *eerb; | |
593 | ||
594 | eerb = (struct eerbuffer *) filp->private_data; | |
3006d7c6 | 595 | if (mutex_lock_interruptible(&readbuffer_mutex)) |
20c64468 SW |
596 | return -ERESTARTSYS; |
597 | ||
598 | spin_lock_irqsave(&bufferlock, flags); | |
599 | ||
600 | if (eerb->residual < 0) { /* the remainder of this record */ | |
601 | /* has been deleted */ | |
602 | eerb->residual = 0; | |
603 | spin_unlock_irqrestore(&bufferlock, flags); | |
3006d7c6 | 604 | mutex_unlock(&readbuffer_mutex); |
20c64468 SW |
605 | return -EIO; |
606 | } else if (eerb->residual > 0) { | |
607 | /* OK we still have a second half of a record to deliver */ | |
608 | effective_count = min(eerb->residual, (int) count); | |
609 | eerb->residual -= effective_count; | |
610 | } else { | |
611 | tc = 0; | |
612 | while (!tc) { | |
613 | tc = dasd_eer_read_buffer(eerb, (char *) &tailcount, | |
614 | sizeof(tailcount)); | |
615 | if (!tc) { | |
616 | /* no data available */ | |
617 | spin_unlock_irqrestore(&bufferlock, flags); | |
3006d7c6 | 618 | mutex_unlock(&readbuffer_mutex); |
20c64468 SW |
619 | if (filp->f_flags & O_NONBLOCK) |
620 | return -EAGAIN; | |
621 | rc = wait_event_interruptible( | |
622 | dasd_eer_read_wait_queue, | |
623 | eerb->head != eerb->tail); | |
624 | if (rc) | |
625 | return rc; | |
3006d7c6 | 626 | if (mutex_lock_interruptible(&readbuffer_mutex)) |
20c64468 SW |
627 | return -ERESTARTSYS; |
628 | spin_lock_irqsave(&bufferlock, flags); | |
629 | } | |
630 | } | |
631 | WARN_ON(tc != sizeof(tailcount)); | |
632 | effective_count = min(tailcount,(int)count); | |
633 | eerb->residual = tailcount - effective_count; | |
634 | } | |
635 | ||
636 | tc = dasd_eer_read_buffer(eerb, readbuffer, effective_count); | |
637 | WARN_ON(tc != effective_count); | |
638 | ||
639 | spin_unlock_irqrestore(&bufferlock, flags); | |
640 | ||
641 | if (copy_to_user(buf, readbuffer, effective_count)) { | |
3006d7c6 | 642 | mutex_unlock(&readbuffer_mutex); |
20c64468 SW |
643 | return -EFAULT; |
644 | } | |
645 | ||
3006d7c6 | 646 | mutex_unlock(&readbuffer_mutex); |
20c64468 SW |
647 | return effective_count; |
648 | } | |
649 | ||
650 | static unsigned int dasd_eer_poll(struct file *filp, poll_table *ptable) | |
651 | { | |
652 | unsigned int mask; | |
653 | unsigned long flags; | |
654 | struct eerbuffer *eerb; | |
655 | ||
656 | eerb = (struct eerbuffer *) filp->private_data; | |
657 | poll_wait(filp, &dasd_eer_read_wait_queue, ptable); | |
658 | spin_lock_irqsave(&bufferlock, flags); | |
659 | if (eerb->head != eerb->tail) | |
660 | mask = POLLIN | POLLRDNORM ; | |
661 | else | |
662 | mask = 0; | |
663 | spin_unlock_irqrestore(&bufferlock, flags); | |
664 | return mask; | |
665 | } | |
666 | ||
d54b1fdb | 667 | static const struct file_operations dasd_eer_fops = { |
20c64468 SW |
668 | .open = &dasd_eer_open, |
669 | .release = &dasd_eer_close, | |
670 | .read = &dasd_eer_read, | |
671 | .poll = &dasd_eer_poll, | |
672 | .owner = THIS_MODULE, | |
6038f373 | 673 | .llseek = noop_llseek, |
20c64468 SW |
674 | }; |
675 | ||
e3c699b3 | 676 | static struct miscdevice *dasd_eer_dev = NULL; |
20c64468 SW |
677 | |
678 | int __init dasd_eer_init(void) | |
679 | { | |
680 | int rc; | |
681 | ||
e3c699b3 SW |
682 | dasd_eer_dev = kzalloc(sizeof(*dasd_eer_dev), GFP_KERNEL); |
683 | if (!dasd_eer_dev) | |
684 | return -ENOMEM; | |
685 | ||
686 | dasd_eer_dev->minor = MISC_DYNAMIC_MINOR; | |
687 | dasd_eer_dev->name = "dasd_eer"; | |
688 | dasd_eer_dev->fops = &dasd_eer_fops; | |
689 | ||
690 | rc = misc_register(dasd_eer_dev); | |
20c64468 | 691 | if (rc) { |
e3c699b3 SW |
692 | kfree(dasd_eer_dev); |
693 | dasd_eer_dev = NULL; | |
fc19f381 | 694 | DBF_EVENT(DBF_ERR, "%s", "dasd_eer_init could not " |
20c64468 SW |
695 | "register misc device"); |
696 | return rc; | |
697 | } | |
698 | ||
699 | return 0; | |
700 | } | |
701 | ||
1375fc1f | 702 | void dasd_eer_exit(void) |
20c64468 | 703 | { |
e3c699b3 | 704 | if (dasd_eer_dev) { |
547415d5 | 705 | misc_deregister(dasd_eer_dev); |
e3c699b3 SW |
706 | kfree(dasd_eer_dev); |
707 | dasd_eer_dev = NULL; | |
708 | } | |
20c64468 | 709 | } |