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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 | ||
9 | #include <linux/init.h> | |
10 | #include <linux/fs.h> | |
11 | #include <linux/kernel.h> | |
12 | #include <linux/miscdevice.h> | |
13 | #include <linux/module.h> | |
14 | #include <linux/moduleparam.h> | |
15 | #include <linux/device.h> | |
16 | #include <linux/poll.h> | |
17 | ||
18 | #include <asm/uaccess.h> | |
19 | #include <asm/semaphore.h> | |
20 | #include <asm/atomic.h> | |
21 | #include <asm/ebcdic.h> | |
22 | ||
23 | #include "dasd_int.h" | |
24 | #include "dasd_eckd.h" | |
25 | ||
26 | #ifdef PRINTK_HEADER | |
27 | #undef PRINTK_HEADER | |
28 | #endif /* PRINTK_HEADER */ | |
29 | #define PRINTK_HEADER "dasd(eer):" | |
30 | ||
31 | /* | |
32 | * SECTION: the internal buffer | |
33 | */ | |
34 | ||
35 | /* | |
36 | * The internal buffer is meant to store obaque blobs of data, so it does | |
37 | * not know of higher level concepts like triggers. | |
38 | * It consists of a number of pages that are used as a ringbuffer. Each data | |
39 | * blob is stored in a simple record that consists of an integer, which | |
40 | * contains the size of the following data, and the data bytes themselfes. | |
41 | * | |
42 | * To allow for multiple independent readers we create one internal buffer | |
43 | * each time the device is opened and destroy the buffer when the file is | |
44 | * closed again. The number of pages used for this buffer is determined by | |
45 | * the module parmeter eer_pages. | |
46 | * | |
47 | * One record can be written to a buffer by using the functions | |
48 | * - dasd_eer_start_record (one time per record to write the size to the | |
49 | * buffer and reserve the space for the data) | |
50 | * - dasd_eer_write_buffer (one or more times per record to write the data) | |
51 | * The data can be written in several steps but you will have to compute | |
52 | * the total size up front for the invocation of dasd_eer_start_record. | |
53 | * If the ringbuffer is full, dasd_eer_start_record will remove the required | |
54 | * number of old records. | |
55 | * | |
56 | * A record is typically read in two steps, first read the integer that | |
57 | * specifies the size of the following data, then read the data. | |
58 | * Both can be done by | |
59 | * - dasd_eer_read_buffer | |
60 | * | |
61 | * For all mentioned functions you need to get the bufferlock first and keep | |
62 | * it until a complete record is written or read. | |
63 | * | |
64 | * All information necessary to keep track of an internal buffer is kept in | |
65 | * a struct eerbuffer. The buffer specific to a file pointer is strored in | |
66 | * the private_data field of that file. To be able to write data to all | |
67 | * existing buffers, each buffer is also added to the bufferlist. | |
68 | * If the user does not want to read a complete record in one go, we have to | |
69 | * keep track of the rest of the record. residual stores the number of bytes | |
70 | * that are still to deliver. If the rest of the record is invalidated between | |
71 | * two reads then residual will be set to -1 so that the next read will fail. | |
72 | * All entries in the eerbuffer structure are protected with the bufferlock. | |
73 | * To avoid races between writing to a buffer on the one side and creating | |
74 | * and destroying buffers on the other side, the bufferlock must also be used | |
75 | * to protect the bufferlist. | |
76 | */ | |
77 | ||
78 | static int eer_pages = 5; | |
79 | module_param(eer_pages, int, S_IRUGO|S_IWUSR); | |
80 | ||
81 | struct eerbuffer { | |
82 | struct list_head list; | |
83 | char **buffer; | |
84 | int buffersize; | |
85 | int buffer_page_count; | |
86 | int head; | |
87 | int tail; | |
88 | int residual; | |
89 | }; | |
90 | ||
91 | static LIST_HEAD(bufferlist); | |
34af946a | 92 | static DEFINE_SPINLOCK(bufferlock); |
20c64468 SW |
93 | static DECLARE_WAIT_QUEUE_HEAD(dasd_eer_read_wait_queue); |
94 | ||
95 | /* | |
96 | * How many free bytes are available on the buffer. | |
97 | * Needs to be called with bufferlock held. | |
98 | */ | |
99 | static int dasd_eer_get_free_bytes(struct eerbuffer *eerb) | |
100 | { | |
101 | if (eerb->head < eerb->tail) | |
102 | return eerb->tail - eerb->head - 1; | |
103 | return eerb->buffersize - eerb->head + eerb->tail -1; | |
104 | } | |
105 | ||
106 | /* | |
107 | * How many bytes of buffer space are used. | |
108 | * Needs to be called with bufferlock held. | |
109 | */ | |
110 | static int dasd_eer_get_filled_bytes(struct eerbuffer *eerb) | |
111 | { | |
112 | ||
113 | if (eerb->head >= eerb->tail) | |
114 | return eerb->head - eerb->tail; | |
115 | return eerb->buffersize - eerb->tail + eerb->head; | |
116 | } | |
117 | ||
118 | /* | |
119 | * The dasd_eer_write_buffer function just copies count bytes of data | |
120 | * to the buffer. Make sure to call dasd_eer_start_record first, to | |
121 | * make sure that enough free space is available. | |
122 | * Needs to be called with bufferlock held. | |
123 | */ | |
124 | static void dasd_eer_write_buffer(struct eerbuffer *eerb, | |
125 | char *data, int count) | |
126 | { | |
127 | ||
128 | unsigned long headindex,localhead; | |
129 | unsigned long rest, len; | |
130 | char *nextdata; | |
131 | ||
132 | nextdata = data; | |
133 | rest = count; | |
134 | while (rest > 0) { | |
135 | headindex = eerb->head / PAGE_SIZE; | |
136 | localhead = eerb->head % PAGE_SIZE; | |
137 | len = min(rest, PAGE_SIZE - localhead); | |
138 | memcpy(eerb->buffer[headindex]+localhead, nextdata, len); | |
139 | nextdata += len; | |
140 | rest -= len; | |
141 | eerb->head += len; | |
142 | if (eerb->head == eerb->buffersize) | |
143 | eerb->head = 0; /* wrap around */ | |
144 | BUG_ON(eerb->head > eerb->buffersize); | |
145 | } | |
146 | } | |
147 | ||
148 | /* | |
149 | * Needs to be called with bufferlock held. | |
150 | */ | |
151 | static int dasd_eer_read_buffer(struct eerbuffer *eerb, char *data, int count) | |
152 | { | |
153 | ||
154 | unsigned long tailindex,localtail; | |
155 | unsigned long rest, len, finalcount; | |
156 | char *nextdata; | |
157 | ||
158 | finalcount = min(count, dasd_eer_get_filled_bytes(eerb)); | |
159 | nextdata = data; | |
160 | rest = finalcount; | |
161 | while (rest > 0) { | |
162 | tailindex = eerb->tail / PAGE_SIZE; | |
163 | localtail = eerb->tail % PAGE_SIZE; | |
164 | len = min(rest, PAGE_SIZE - localtail); | |
165 | memcpy(nextdata, eerb->buffer[tailindex] + localtail, len); | |
166 | nextdata += len; | |
167 | rest -= len; | |
168 | eerb->tail += len; | |
169 | if (eerb->tail == eerb->buffersize) | |
170 | eerb->tail = 0; /* wrap around */ | |
171 | BUG_ON(eerb->tail > eerb->buffersize); | |
172 | } | |
173 | return finalcount; | |
174 | } | |
175 | ||
176 | /* | |
177 | * Whenever you want to write a blob of data to the internal buffer you | |
178 | * have to start by using this function first. It will write the number | |
179 | * of bytes that will be written to the buffer. If necessary it will remove | |
180 | * old records to make room for the new one. | |
181 | * Needs to be called with bufferlock held. | |
182 | */ | |
183 | static int dasd_eer_start_record(struct eerbuffer *eerb, int count) | |
184 | { | |
185 | int tailcount; | |
186 | ||
187 | if (count + sizeof(count) > eerb->buffersize) | |
188 | return -ENOMEM; | |
189 | while (dasd_eer_get_free_bytes(eerb) < count + sizeof(count)) { | |
190 | if (eerb->residual > 0) { | |
191 | eerb->tail += eerb->residual; | |
192 | if (eerb->tail >= eerb->buffersize) | |
193 | eerb->tail -= eerb->buffersize; | |
194 | eerb->residual = -1; | |
195 | } | |
196 | dasd_eer_read_buffer(eerb, (char *) &tailcount, | |
197 | sizeof(tailcount)); | |
198 | eerb->tail += tailcount; | |
199 | if (eerb->tail >= eerb->buffersize) | |
200 | eerb->tail -= eerb->buffersize; | |
201 | } | |
202 | dasd_eer_write_buffer(eerb, (char*) &count, sizeof(count)); | |
203 | ||
204 | return 0; | |
205 | }; | |
206 | ||
207 | /* | |
208 | * Release pages that are not used anymore. | |
209 | */ | |
210 | static void dasd_eer_free_buffer_pages(char **buf, int no_pages) | |
211 | { | |
212 | int i; | |
213 | ||
214 | for (i = 0; i < no_pages; i++) | |
215 | free_page((unsigned long) buf[i]); | |
216 | } | |
217 | ||
218 | /* | |
219 | * Allocate a new set of memory pages. | |
220 | */ | |
221 | static int dasd_eer_allocate_buffer_pages(char **buf, int no_pages) | |
222 | { | |
223 | int i; | |
224 | ||
225 | for (i = 0; i < no_pages; i++) { | |
226 | buf[i] = (char *) get_zeroed_page(GFP_KERNEL); | |
227 | if (!buf[i]) { | |
228 | dasd_eer_free_buffer_pages(buf, i); | |
229 | return -ENOMEM; | |
230 | } | |
231 | } | |
232 | return 0; | |
233 | } | |
234 | ||
235 | /* | |
236 | * SECTION: The extended error reporting functionality | |
237 | */ | |
238 | ||
239 | /* | |
240 | * When a DASD device driver wants to report an error, it calls the | |
241 | * function dasd_eer_write and gives the respective trigger ID as | |
242 | * parameter. Currently there are four kinds of triggers: | |
243 | * | |
244 | * DASD_EER_FATALERROR: all kinds of unrecoverable I/O problems | |
245 | * DASD_EER_PPRCSUSPEND: PPRC was suspended | |
246 | * DASD_EER_NOPATH: There is no path to the device left. | |
247 | * DASD_EER_STATECHANGE: The state of the device has changed. | |
248 | * | |
249 | * For the first three triggers all required information can be supplied by | |
250 | * the caller. For these triggers a record is written by the function | |
251 | * dasd_eer_write_standard_trigger. | |
252 | * | |
253 | * The DASD_EER_STATECHANGE trigger is special since a sense subsystem | |
254 | * status ccw need to be executed to gather the necessary sense data first. | |
255 | * The dasd_eer_snss function will queue the SNSS request and the request | |
256 | * callback will then call dasd_eer_write with the DASD_EER_STATCHANGE | |
257 | * trigger. | |
258 | * | |
259 | * To avoid memory allocations at runtime, the necessary memory is allocated | |
260 | * when the extended error reporting is enabled for a device (by | |
261 | * dasd_eer_probe). There is one sense subsystem status request for each | |
262 | * eer enabled DASD device. The presence of the cqr in device->eer_cqr | |
263 | * indicates that eer is enable for the device. The use of the snss request | |
264 | * is protected by the DASD_FLAG_EER_IN_USE bit. When this flag indicates | |
265 | * that the cqr is currently in use, dasd_eer_snss cannot start a second | |
266 | * request but sets the DASD_FLAG_EER_SNSS flag instead. The callback of | |
267 | * the SNSS request will check the bit and call dasd_eer_snss again. | |
268 | */ | |
269 | ||
270 | #define SNSS_DATA_SIZE 44 | |
271 | ||
272 | #define DASD_EER_BUSID_SIZE 10 | |
273 | struct dasd_eer_header { | |
274 | __u32 total_size; | |
275 | __u32 trigger; | |
276 | __u64 tv_sec; | |
277 | __u64 tv_usec; | |
278 | char busid[DASD_EER_BUSID_SIZE]; | |
774fc4ef | 279 | } __attribute__ ((packed)); |
20c64468 SW |
280 | |
281 | /* | |
282 | * The following function can be used for those triggers that have | |
283 | * all necessary data available when the function is called. | |
284 | * If the parameter cqr is not NULL, the chain of requests will be searched | |
285 | * for valid sense data, and all valid sense data sets will be added to | |
286 | * the triggers data. | |
287 | */ | |
288 | static void dasd_eer_write_standard_trigger(struct dasd_device *device, | |
289 | struct dasd_ccw_req *cqr, | |
290 | int trigger) | |
291 | { | |
292 | struct dasd_ccw_req *temp_cqr; | |
293 | int data_size; | |
294 | struct timeval tv; | |
295 | struct dasd_eer_header header; | |
296 | unsigned long flags; | |
297 | struct eerbuffer *eerb; | |
298 | ||
299 | /* go through cqr chain and count the valid sense data sets */ | |
300 | data_size = 0; | |
301 | for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) | |
302 | if (temp_cqr->irb.esw.esw0.erw.cons) | |
303 | data_size += 32; | |
304 | ||
305 | header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ | |
306 | header.trigger = trigger; | |
307 | do_gettimeofday(&tv); | |
308 | header.tv_sec = tv.tv_sec; | |
309 | header.tv_usec = tv.tv_usec; | |
310 | strncpy(header.busid, device->cdev->dev.bus_id, DASD_EER_BUSID_SIZE); | |
311 | ||
312 | spin_lock_irqsave(&bufferlock, flags); | |
313 | list_for_each_entry(eerb, &bufferlist, list) { | |
314 | dasd_eer_start_record(eerb, header.total_size); | |
315 | dasd_eer_write_buffer(eerb, (char *) &header, sizeof(header)); | |
316 | for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) | |
317 | if (temp_cqr->irb.esw.esw0.erw.cons) | |
318 | dasd_eer_write_buffer(eerb, cqr->irb.ecw, 32); | |
319 | dasd_eer_write_buffer(eerb, "EOR", 4); | |
320 | } | |
321 | spin_unlock_irqrestore(&bufferlock, flags); | |
322 | wake_up_interruptible(&dasd_eer_read_wait_queue); | |
323 | } | |
324 | ||
325 | /* | |
326 | * This function writes a DASD_EER_STATECHANGE trigger. | |
327 | */ | |
328 | static void dasd_eer_write_snss_trigger(struct dasd_device *device, | |
329 | struct dasd_ccw_req *cqr, | |
330 | int trigger) | |
331 | { | |
332 | int data_size; | |
333 | int snss_rc; | |
334 | struct timeval tv; | |
335 | struct dasd_eer_header header; | |
336 | unsigned long flags; | |
337 | struct eerbuffer *eerb; | |
338 | ||
339 | snss_rc = (cqr->status == DASD_CQR_FAILED) ? -EIO : 0; | |
340 | if (snss_rc) | |
341 | data_size = 0; | |
342 | else | |
343 | data_size = SNSS_DATA_SIZE; | |
344 | ||
345 | header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ | |
346 | header.trigger = DASD_EER_STATECHANGE; | |
347 | do_gettimeofday(&tv); | |
348 | header.tv_sec = tv.tv_sec; | |
349 | header.tv_usec = tv.tv_usec; | |
350 | strncpy(header.busid, device->cdev->dev.bus_id, DASD_EER_BUSID_SIZE); | |
351 | ||
352 | spin_lock_irqsave(&bufferlock, flags); | |
353 | list_for_each_entry(eerb, &bufferlist, list) { | |
354 | dasd_eer_start_record(eerb, header.total_size); | |
355 | dasd_eer_write_buffer(eerb, (char *) &header , sizeof(header)); | |
356 | if (!snss_rc) | |
357 | dasd_eer_write_buffer(eerb, cqr->data, SNSS_DATA_SIZE); | |
358 | dasd_eer_write_buffer(eerb, "EOR", 4); | |
359 | } | |
360 | spin_unlock_irqrestore(&bufferlock, flags); | |
361 | wake_up_interruptible(&dasd_eer_read_wait_queue); | |
362 | } | |
363 | ||
364 | /* | |
365 | * This function is called for all triggers. It calls the appropriate | |
366 | * function that writes the actual trigger records. | |
367 | */ | |
368 | void dasd_eer_write(struct dasd_device *device, struct dasd_ccw_req *cqr, | |
369 | unsigned int id) | |
370 | { | |
371 | if (!device->eer_cqr) | |
372 | return; | |
373 | switch (id) { | |
374 | case DASD_EER_FATALERROR: | |
375 | case DASD_EER_PPRCSUSPEND: | |
376 | dasd_eer_write_standard_trigger(device, cqr, id); | |
377 | break; | |
378 | case DASD_EER_NOPATH: | |
379 | dasd_eer_write_standard_trigger(device, NULL, id); | |
380 | break; | |
381 | case DASD_EER_STATECHANGE: | |
382 | dasd_eer_write_snss_trigger(device, cqr, id); | |
383 | break; | |
384 | default: /* unknown trigger, so we write it without any sense data */ | |
385 | dasd_eer_write_standard_trigger(device, NULL, id); | |
386 | break; | |
387 | } | |
388 | } | |
389 | EXPORT_SYMBOL(dasd_eer_write); | |
390 | ||
391 | /* | |
392 | * Start a sense subsystem status request. | |
393 | * Needs to be called with the device held. | |
394 | */ | |
395 | void dasd_eer_snss(struct dasd_device *device) | |
396 | { | |
397 | struct dasd_ccw_req *cqr; | |
398 | ||
399 | cqr = device->eer_cqr; | |
400 | if (!cqr) /* Device not eer enabled. */ | |
401 | return; | |
402 | if (test_and_set_bit(DASD_FLAG_EER_IN_USE, &device->flags)) { | |
403 | /* Sense subsystem status request in use. */ | |
404 | set_bit(DASD_FLAG_EER_SNSS, &device->flags); | |
405 | return; | |
406 | } | |
407 | clear_bit(DASD_FLAG_EER_SNSS, &device->flags); | |
408 | cqr->status = DASD_CQR_QUEUED; | |
409 | list_add(&cqr->list, &device->ccw_queue); | |
410 | dasd_schedule_bh(device); | |
411 | } | |
412 | ||
413 | /* | |
414 | * Callback function for use with sense subsystem status request. | |
415 | */ | |
416 | static void dasd_eer_snss_cb(struct dasd_ccw_req *cqr, void *data) | |
417 | { | |
418 | struct dasd_device *device = cqr->device; | |
419 | unsigned long flags; | |
420 | ||
421 | dasd_eer_write(device, cqr, DASD_EER_STATECHANGE); | |
422 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); | |
423 | if (device->eer_cqr == cqr) { | |
424 | clear_bit(DASD_FLAG_EER_IN_USE, &device->flags); | |
425 | if (test_bit(DASD_FLAG_EER_SNSS, &device->flags)) | |
426 | /* Another SNSS has been requested in the meantime. */ | |
427 | dasd_eer_snss(device); | |
428 | cqr = NULL; | |
429 | } | |
430 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); | |
431 | if (cqr) | |
432 | /* | |
433 | * Extended error recovery has been switched off while | |
434 | * the SNSS request was running. It could even have | |
435 | * been switched off and on again in which case there | |
436 | * is a new ccw in device->eer_cqr. Free the "old" | |
437 | * snss request now. | |
438 | */ | |
439 | dasd_kfree_request(cqr, device); | |
440 | } | |
441 | ||
442 | /* | |
443 | * Enable error reporting on a given device. | |
444 | */ | |
445 | int dasd_eer_enable(struct dasd_device *device) | |
446 | { | |
447 | struct dasd_ccw_req *cqr; | |
448 | unsigned long flags; | |
449 | ||
450 | if (device->eer_cqr) | |
451 | return 0; | |
452 | ||
453 | if (!device->discipline || strcmp(device->discipline->name, "ECKD")) | |
454 | return -EPERM; /* FIXME: -EMEDIUMTYPE ? */ | |
455 | ||
456 | cqr = dasd_kmalloc_request("ECKD", 1 /* SNSS */, | |
457 | SNSS_DATA_SIZE, device); | |
458 | if (!cqr) | |
459 | return -ENOMEM; | |
460 | ||
461 | cqr->device = device; | |
462 | cqr->retries = 255; | |
463 | cqr->expires = 10 * HZ; | |
464 | ||
465 | cqr->cpaddr->cmd_code = DASD_ECKD_CCW_SNSS; | |
466 | cqr->cpaddr->count = SNSS_DATA_SIZE; | |
467 | cqr->cpaddr->flags = 0; | |
468 | cqr->cpaddr->cda = (__u32)(addr_t) cqr->data; | |
469 | ||
470 | cqr->buildclk = get_clock(); | |
471 | cqr->status = DASD_CQR_FILLED; | |
472 | cqr->callback = dasd_eer_snss_cb; | |
473 | ||
474 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); | |
475 | if (!device->eer_cqr) { | |
476 | device->eer_cqr = cqr; | |
477 | cqr = NULL; | |
478 | } | |
479 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); | |
480 | if (cqr) | |
481 | dasd_kfree_request(cqr, device); | |
482 | return 0; | |
483 | } | |
484 | ||
485 | /* | |
486 | * Disable error reporting on a given device. | |
487 | */ | |
488 | void dasd_eer_disable(struct dasd_device *device) | |
489 | { | |
490 | struct dasd_ccw_req *cqr; | |
491 | unsigned long flags; | |
492 | int in_use; | |
493 | ||
494 | if (!device->eer_cqr) | |
495 | return; | |
496 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); | |
497 | cqr = device->eer_cqr; | |
498 | device->eer_cqr = NULL; | |
499 | clear_bit(DASD_FLAG_EER_SNSS, &device->flags); | |
500 | in_use = test_and_clear_bit(DASD_FLAG_EER_IN_USE, &device->flags); | |
501 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); | |
502 | if (cqr && !in_use) | |
503 | dasd_kfree_request(cqr, device); | |
504 | } | |
505 | ||
506 | /* | |
507 | * SECTION: the device operations | |
508 | */ | |
509 | ||
510 | /* | |
511 | * On the one side we need a lock to access our internal buffer, on the | |
512 | * other side a copy_to_user can sleep. So we need to copy the data we have | |
513 | * to transfer in a readbuffer, which is protected by the readbuffer_mutex. | |
514 | */ | |
515 | static char readbuffer[PAGE_SIZE]; | |
516 | static DECLARE_MUTEX(readbuffer_mutex); | |
517 | ||
518 | static int dasd_eer_open(struct inode *inp, struct file *filp) | |
519 | { | |
520 | struct eerbuffer *eerb; | |
521 | unsigned long flags; | |
522 | ||
523 | eerb = kzalloc(sizeof(struct eerbuffer), GFP_KERNEL); | |
f45a43d8 SW |
524 | if (!eerb) |
525 | return -ENOMEM; | |
20c64468 SW |
526 | eerb->buffer_page_count = eer_pages; |
527 | if (eerb->buffer_page_count < 1 || | |
528 | eerb->buffer_page_count > INT_MAX / PAGE_SIZE) { | |
529 | kfree(eerb); | |
530 | MESSAGE(KERN_WARNING, "can't open device since module " | |
531 | "parameter eer_pages is smaller then 1 or" | |
532 | " bigger then %d", (int)(INT_MAX / PAGE_SIZE)); | |
533 | return -EINVAL; | |
534 | } | |
535 | eerb->buffersize = eerb->buffer_page_count * PAGE_SIZE; | |
536 | eerb->buffer = kmalloc(eerb->buffer_page_count * sizeof(char *), | |
537 | GFP_KERNEL); | |
538 | if (!eerb->buffer) { | |
539 | kfree(eerb); | |
540 | return -ENOMEM; | |
541 | } | |
542 | if (dasd_eer_allocate_buffer_pages(eerb->buffer, | |
543 | eerb->buffer_page_count)) { | |
544 | kfree(eerb->buffer); | |
545 | kfree(eerb); | |
546 | return -ENOMEM; | |
547 | } | |
548 | filp->private_data = eerb; | |
549 | spin_lock_irqsave(&bufferlock, flags); | |
550 | list_add(&eerb->list, &bufferlist); | |
551 | spin_unlock_irqrestore(&bufferlock, flags); | |
552 | ||
553 | return nonseekable_open(inp,filp); | |
554 | } | |
555 | ||
556 | static int dasd_eer_close(struct inode *inp, struct file *filp) | |
557 | { | |
558 | struct eerbuffer *eerb; | |
559 | unsigned long flags; | |
560 | ||
561 | eerb = (struct eerbuffer *) filp->private_data; | |
562 | spin_lock_irqsave(&bufferlock, flags); | |
563 | list_del(&eerb->list); | |
564 | spin_unlock_irqrestore(&bufferlock, flags); | |
565 | dasd_eer_free_buffer_pages(eerb->buffer, eerb->buffer_page_count); | |
566 | kfree(eerb->buffer); | |
567 | kfree(eerb); | |
568 | ||
569 | return 0; | |
570 | } | |
571 | ||
572 | static ssize_t dasd_eer_read(struct file *filp, char __user *buf, | |
573 | size_t count, loff_t *ppos) | |
574 | { | |
575 | int tc,rc; | |
576 | int tailcount,effective_count; | |
577 | unsigned long flags; | |
578 | struct eerbuffer *eerb; | |
579 | ||
580 | eerb = (struct eerbuffer *) filp->private_data; | |
581 | if (down_interruptible(&readbuffer_mutex)) | |
582 | return -ERESTARTSYS; | |
583 | ||
584 | spin_lock_irqsave(&bufferlock, flags); | |
585 | ||
586 | if (eerb->residual < 0) { /* the remainder of this record */ | |
587 | /* has been deleted */ | |
588 | eerb->residual = 0; | |
589 | spin_unlock_irqrestore(&bufferlock, flags); | |
590 | up(&readbuffer_mutex); | |
591 | return -EIO; | |
592 | } else if (eerb->residual > 0) { | |
593 | /* OK we still have a second half of a record to deliver */ | |
594 | effective_count = min(eerb->residual, (int) count); | |
595 | eerb->residual -= effective_count; | |
596 | } else { | |
597 | tc = 0; | |
598 | while (!tc) { | |
599 | tc = dasd_eer_read_buffer(eerb, (char *) &tailcount, | |
600 | sizeof(tailcount)); | |
601 | if (!tc) { | |
602 | /* no data available */ | |
603 | spin_unlock_irqrestore(&bufferlock, flags); | |
604 | up(&readbuffer_mutex); | |
605 | if (filp->f_flags & O_NONBLOCK) | |
606 | return -EAGAIN; | |
607 | rc = wait_event_interruptible( | |
608 | dasd_eer_read_wait_queue, | |
609 | eerb->head != eerb->tail); | |
610 | if (rc) | |
611 | return rc; | |
612 | if (down_interruptible(&readbuffer_mutex)) | |
613 | return -ERESTARTSYS; | |
614 | spin_lock_irqsave(&bufferlock, flags); | |
615 | } | |
616 | } | |
617 | WARN_ON(tc != sizeof(tailcount)); | |
618 | effective_count = min(tailcount,(int)count); | |
619 | eerb->residual = tailcount - effective_count; | |
620 | } | |
621 | ||
622 | tc = dasd_eer_read_buffer(eerb, readbuffer, effective_count); | |
623 | WARN_ON(tc != effective_count); | |
624 | ||
625 | spin_unlock_irqrestore(&bufferlock, flags); | |
626 | ||
627 | if (copy_to_user(buf, readbuffer, effective_count)) { | |
628 | up(&readbuffer_mutex); | |
629 | return -EFAULT; | |
630 | } | |
631 | ||
632 | up(&readbuffer_mutex); | |
633 | return effective_count; | |
634 | } | |
635 | ||
636 | static unsigned int dasd_eer_poll(struct file *filp, poll_table *ptable) | |
637 | { | |
638 | unsigned int mask; | |
639 | unsigned long flags; | |
640 | struct eerbuffer *eerb; | |
641 | ||
642 | eerb = (struct eerbuffer *) filp->private_data; | |
643 | poll_wait(filp, &dasd_eer_read_wait_queue, ptable); | |
644 | spin_lock_irqsave(&bufferlock, flags); | |
645 | if (eerb->head != eerb->tail) | |
646 | mask = POLLIN | POLLRDNORM ; | |
647 | else | |
648 | mask = 0; | |
649 | spin_unlock_irqrestore(&bufferlock, flags); | |
650 | return mask; | |
651 | } | |
652 | ||
d54b1fdb | 653 | static const struct file_operations dasd_eer_fops = { |
20c64468 SW |
654 | .open = &dasd_eer_open, |
655 | .release = &dasd_eer_close, | |
656 | .read = &dasd_eer_read, | |
657 | .poll = &dasd_eer_poll, | |
658 | .owner = THIS_MODULE, | |
659 | }; | |
660 | ||
e3c699b3 | 661 | static struct miscdevice *dasd_eer_dev = NULL; |
20c64468 SW |
662 | |
663 | int __init dasd_eer_init(void) | |
664 | { | |
665 | int rc; | |
666 | ||
e3c699b3 SW |
667 | dasd_eer_dev = kzalloc(sizeof(*dasd_eer_dev), GFP_KERNEL); |
668 | if (!dasd_eer_dev) | |
669 | return -ENOMEM; | |
670 | ||
671 | dasd_eer_dev->minor = MISC_DYNAMIC_MINOR; | |
672 | dasd_eer_dev->name = "dasd_eer"; | |
673 | dasd_eer_dev->fops = &dasd_eer_fops; | |
674 | ||
675 | rc = misc_register(dasd_eer_dev); | |
20c64468 | 676 | if (rc) { |
e3c699b3 SW |
677 | kfree(dasd_eer_dev); |
678 | dasd_eer_dev = NULL; | |
20c64468 SW |
679 | MESSAGE(KERN_ERR, "%s", "dasd_eer_init could not " |
680 | "register misc device"); | |
681 | return rc; | |
682 | } | |
683 | ||
684 | return 0; | |
685 | } | |
686 | ||
1375fc1f | 687 | void dasd_eer_exit(void) |
20c64468 | 688 | { |
e3c699b3 SW |
689 | if (dasd_eer_dev) { |
690 | WARN_ON(misc_deregister(dasd_eer_dev) != 0); | |
691 | kfree(dasd_eer_dev); | |
692 | dasd_eer_dev = NULL; | |
693 | } | |
20c64468 | 694 | } |