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20c64468 SW |
1 | /* |
2 | * Character device driver for extended error reporting. | |
3 | * | |
a53c8fab | 4 | * Copyright IBM Corp. 2005 |
20c64468 SW |
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> |
0983e568 | 20 | #include <linux/err.h> |
5a0e3ad6 | 21 | #include <linux/slab.h> |
20c64468 SW |
22 | |
23 | #include <asm/uaccess.h> | |
60063497 | 24 | #include <linux/atomic.h> |
20c64468 SW |
25 | #include <asm/ebcdic.h> |
26 | ||
27 | #include "dasd_int.h" | |
28 | #include "dasd_eckd.h" | |
29 | ||
30 | #ifdef PRINTK_HEADER | |
31 | #undef PRINTK_HEADER | |
32 | #endif /* PRINTK_HEADER */ | |
33 | #define PRINTK_HEADER "dasd(eer):" | |
34 | ||
35 | /* | |
36 | * SECTION: the internal buffer | |
37 | */ | |
38 | ||
39 | /* | |
40 | * The internal buffer is meant to store obaque blobs of data, so it does | |
41 | * not know of higher level concepts like triggers. | |
42 | * It consists of a number of pages that are used as a ringbuffer. Each data | |
43 | * blob is stored in a simple record that consists of an integer, which | |
44 | * contains the size of the following data, and the data bytes themselfes. | |
45 | * | |
46 | * To allow for multiple independent readers we create one internal buffer | |
47 | * each time the device is opened and destroy the buffer when the file is | |
48 | * closed again. The number of pages used for this buffer is determined by | |
49 | * the module parmeter eer_pages. | |
50 | * | |
51 | * One record can be written to a buffer by using the functions | |
52 | * - dasd_eer_start_record (one time per record to write the size to the | |
53 | * buffer and reserve the space for the data) | |
54 | * - dasd_eer_write_buffer (one or more times per record to write the data) | |
55 | * The data can be written in several steps but you will have to compute | |
56 | * the total size up front for the invocation of dasd_eer_start_record. | |
57 | * If the ringbuffer is full, dasd_eer_start_record will remove the required | |
58 | * number of old records. | |
59 | * | |
60 | * A record is typically read in two steps, first read the integer that | |
61 | * specifies the size of the following data, then read the data. | |
62 | * Both can be done by | |
63 | * - dasd_eer_read_buffer | |
64 | * | |
65 | * For all mentioned functions you need to get the bufferlock first and keep | |
66 | * it until a complete record is written or read. | |
67 | * | |
68 | * All information necessary to keep track of an internal buffer is kept in | |
69 | * a struct eerbuffer. The buffer specific to a file pointer is strored in | |
70 | * the private_data field of that file. To be able to write data to all | |
71 | * existing buffers, each buffer is also added to the bufferlist. | |
72 | * If the user does not want to read a complete record in one go, we have to | |
73 | * keep track of the rest of the record. residual stores the number of bytes | |
74 | * that are still to deliver. If the rest of the record is invalidated between | |
75 | * two reads then residual will be set to -1 so that the next read will fail. | |
76 | * All entries in the eerbuffer structure are protected with the bufferlock. | |
77 | * To avoid races between writing to a buffer on the one side and creating | |
78 | * and destroying buffers on the other side, the bufferlock must also be used | |
79 | * to protect the bufferlist. | |
80 | */ | |
81 | ||
82 | static int eer_pages = 5; | |
83 | module_param(eer_pages, int, S_IRUGO|S_IWUSR); | |
84 | ||
85 | struct eerbuffer { | |
86 | struct list_head list; | |
87 | char **buffer; | |
88 | int buffersize; | |
89 | int buffer_page_count; | |
90 | int head; | |
91 | int tail; | |
92 | int residual; | |
93 | }; | |
94 | ||
95 | static LIST_HEAD(bufferlist); | |
34af946a | 96 | static DEFINE_SPINLOCK(bufferlock); |
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97 | static DECLARE_WAIT_QUEUE_HEAD(dasd_eer_read_wait_queue); |
98 | ||
99 | /* | |
100 | * How many free bytes are available on the buffer. | |
101 | * Needs to be called with bufferlock held. | |
102 | */ | |
103 | static int dasd_eer_get_free_bytes(struct eerbuffer *eerb) | |
104 | { | |
105 | if (eerb->head < eerb->tail) | |
106 | return eerb->tail - eerb->head - 1; | |
107 | return eerb->buffersize - eerb->head + eerb->tail -1; | |
108 | } | |
109 | ||
110 | /* | |
111 | * How many bytes of buffer space are used. | |
112 | * Needs to be called with bufferlock held. | |
113 | */ | |
114 | static int dasd_eer_get_filled_bytes(struct eerbuffer *eerb) | |
115 | { | |
116 | ||
117 | if (eerb->head >= eerb->tail) | |
118 | return eerb->head - eerb->tail; | |
119 | return eerb->buffersize - eerb->tail + eerb->head; | |
120 | } | |
121 | ||
122 | /* | |
123 | * The dasd_eer_write_buffer function just copies count bytes of data | |
124 | * to the buffer. Make sure to call dasd_eer_start_record first, to | |
125 | * make sure that enough free space is available. | |
126 | * Needs to be called with bufferlock held. | |
127 | */ | |
128 | static void dasd_eer_write_buffer(struct eerbuffer *eerb, | |
129 | char *data, int count) | |
130 | { | |
131 | ||
132 | unsigned long headindex,localhead; | |
133 | unsigned long rest, len; | |
134 | char *nextdata; | |
135 | ||
136 | nextdata = data; | |
137 | rest = count; | |
138 | while (rest > 0) { | |
139 | headindex = eerb->head / PAGE_SIZE; | |
140 | localhead = eerb->head % PAGE_SIZE; | |
141 | len = min(rest, PAGE_SIZE - localhead); | |
142 | memcpy(eerb->buffer[headindex]+localhead, nextdata, len); | |
143 | nextdata += len; | |
144 | rest -= len; | |
145 | eerb->head += len; | |
146 | if (eerb->head == eerb->buffersize) | |
147 | eerb->head = 0; /* wrap around */ | |
148 | BUG_ON(eerb->head > eerb->buffersize); | |
149 | } | |
150 | } | |
151 | ||
152 | /* | |
153 | * Needs to be called with bufferlock held. | |
154 | */ | |
155 | static int dasd_eer_read_buffer(struct eerbuffer *eerb, char *data, int count) | |
156 | { | |
157 | ||
158 | unsigned long tailindex,localtail; | |
159 | unsigned long rest, len, finalcount; | |
160 | char *nextdata; | |
161 | ||
162 | finalcount = min(count, dasd_eer_get_filled_bytes(eerb)); | |
163 | nextdata = data; | |
164 | rest = finalcount; | |
165 | while (rest > 0) { | |
166 | tailindex = eerb->tail / PAGE_SIZE; | |
167 | localtail = eerb->tail % PAGE_SIZE; | |
168 | len = min(rest, PAGE_SIZE - localtail); | |
169 | memcpy(nextdata, eerb->buffer[tailindex] + localtail, len); | |
170 | nextdata += len; | |
171 | rest -= len; | |
172 | eerb->tail += len; | |
173 | if (eerb->tail == eerb->buffersize) | |
174 | eerb->tail = 0; /* wrap around */ | |
175 | BUG_ON(eerb->tail > eerb->buffersize); | |
176 | } | |
177 | return finalcount; | |
178 | } | |
179 | ||
180 | /* | |
181 | * Whenever you want to write a blob of data to the internal buffer you | |
182 | * have to start by using this function first. It will write the number | |
183 | * of bytes that will be written to the buffer. If necessary it will remove | |
184 | * old records to make room for the new one. | |
185 | * Needs to be called with bufferlock held. | |
186 | */ | |
187 | static int dasd_eer_start_record(struct eerbuffer *eerb, int count) | |
188 | { | |
189 | int tailcount; | |
190 | ||
191 | if (count + sizeof(count) > eerb->buffersize) | |
192 | return -ENOMEM; | |
193 | while (dasd_eer_get_free_bytes(eerb) < count + sizeof(count)) { | |
194 | if (eerb->residual > 0) { | |
195 | eerb->tail += eerb->residual; | |
196 | if (eerb->tail >= eerb->buffersize) | |
197 | eerb->tail -= eerb->buffersize; | |
198 | eerb->residual = -1; | |
199 | } | |
200 | dasd_eer_read_buffer(eerb, (char *) &tailcount, | |
201 | sizeof(tailcount)); | |
202 | eerb->tail += tailcount; | |
203 | if (eerb->tail >= eerb->buffersize) | |
204 | eerb->tail -= eerb->buffersize; | |
205 | } | |
206 | dasd_eer_write_buffer(eerb, (char*) &count, sizeof(count)); | |
207 | ||
208 | return 0; | |
209 | }; | |
210 | ||
211 | /* | |
212 | * Release pages that are not used anymore. | |
213 | */ | |
214 | static void dasd_eer_free_buffer_pages(char **buf, int no_pages) | |
215 | { | |
216 | int i; | |
217 | ||
218 | for (i = 0; i < no_pages; i++) | |
219 | free_page((unsigned long) buf[i]); | |
220 | } | |
221 | ||
222 | /* | |
223 | * Allocate a new set of memory pages. | |
224 | */ | |
225 | static int dasd_eer_allocate_buffer_pages(char **buf, int no_pages) | |
226 | { | |
227 | int i; | |
228 | ||
229 | for (i = 0; i < no_pages; i++) { | |
230 | buf[i] = (char *) get_zeroed_page(GFP_KERNEL); | |
231 | if (!buf[i]) { | |
232 | dasd_eer_free_buffer_pages(buf, i); | |
233 | return -ENOMEM; | |
234 | } | |
235 | } | |
236 | return 0; | |
237 | } | |
238 | ||
239 | /* | |
240 | * SECTION: The extended error reporting functionality | |
241 | */ | |
242 | ||
243 | /* | |
244 | * When a DASD device driver wants to report an error, it calls the | |
245 | * function dasd_eer_write and gives the respective trigger ID as | |
246 | * parameter. Currently there are four kinds of triggers: | |
247 | * | |
248 | * DASD_EER_FATALERROR: all kinds of unrecoverable I/O problems | |
249 | * DASD_EER_PPRCSUSPEND: PPRC was suspended | |
250 | * DASD_EER_NOPATH: There is no path to the device left. | |
251 | * DASD_EER_STATECHANGE: The state of the device has changed. | |
252 | * | |
253 | * For the first three triggers all required information can be supplied by | |
254 | * the caller. For these triggers a record is written by the function | |
255 | * dasd_eer_write_standard_trigger. | |
256 | * | |
257 | * The DASD_EER_STATECHANGE trigger is special since a sense subsystem | |
258 | * status ccw need to be executed to gather the necessary sense data first. | |
259 | * The dasd_eer_snss function will queue the SNSS request and the request | |
260 | * callback will then call dasd_eer_write with the DASD_EER_STATCHANGE | |
261 | * trigger. | |
262 | * | |
263 | * To avoid memory allocations at runtime, the necessary memory is allocated | |
264 | * when the extended error reporting is enabled for a device (by | |
265 | * dasd_eer_probe). There is one sense subsystem status request for each | |
266 | * eer enabled DASD device. The presence of the cqr in device->eer_cqr | |
267 | * indicates that eer is enable for the device. The use of the snss request | |
268 | * is protected by the DASD_FLAG_EER_IN_USE bit. When this flag indicates | |
269 | * that the cqr is currently in use, dasd_eer_snss cannot start a second | |
270 | * request but sets the DASD_FLAG_EER_SNSS flag instead. The callback of | |
271 | * the SNSS request will check the bit and call dasd_eer_snss again. | |
272 | */ | |
273 | ||
274 | #define SNSS_DATA_SIZE 44 | |
275 | ||
276 | #define DASD_EER_BUSID_SIZE 10 | |
277 | struct dasd_eer_header { | |
278 | __u32 total_size; | |
279 | __u32 trigger; | |
280 | __u64 tv_sec; | |
281 | __u64 tv_usec; | |
282 | char busid[DASD_EER_BUSID_SIZE]; | |
774fc4ef | 283 | } __attribute__ ((packed)); |
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284 | |
285 | /* | |
286 | * The following function can be used for those triggers that have | |
287 | * all necessary data available when the function is called. | |
288 | * If the parameter cqr is not NULL, the chain of requests will be searched | |
289 | * for valid sense data, and all valid sense data sets will be added to | |
290 | * the triggers data. | |
291 | */ | |
292 | static void dasd_eer_write_standard_trigger(struct dasd_device *device, | |
293 | struct dasd_ccw_req *cqr, | |
294 | int trigger) | |
295 | { | |
296 | struct dasd_ccw_req *temp_cqr; | |
297 | int data_size; | |
298 | struct timeval tv; | |
299 | struct dasd_eer_header header; | |
300 | unsigned long flags; | |
301 | struct eerbuffer *eerb; | |
f3eb5384 | 302 | char *sense; |
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303 | |
304 | /* go through cqr chain and count the valid sense data sets */ | |
305 | data_size = 0; | |
306 | for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) | |
f3eb5384 | 307 | if (dasd_get_sense(&temp_cqr->irb)) |
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308 | data_size += 32; |
309 | ||
310 | header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ | |
311 | header.trigger = trigger; | |
312 | do_gettimeofday(&tv); | |
313 | header.tv_sec = tv.tv_sec; | |
314 | header.tv_usec = tv.tv_usec; | |
2a0217d5 KS |
315 | strncpy(header.busid, dev_name(&device->cdev->dev), |
316 | DASD_EER_BUSID_SIZE); | |
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317 | |
318 | spin_lock_irqsave(&bufferlock, flags); | |
319 | list_for_each_entry(eerb, &bufferlist, list) { | |
320 | dasd_eer_start_record(eerb, header.total_size); | |
321 | dasd_eer_write_buffer(eerb, (char *) &header, sizeof(header)); | |
f3eb5384 SW |
322 | for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) { |
323 | sense = dasd_get_sense(&temp_cqr->irb); | |
324 | if (sense) | |
325 | dasd_eer_write_buffer(eerb, sense, 32); | |
326 | } | |
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327 | dasd_eer_write_buffer(eerb, "EOR", 4); |
328 | } | |
329 | spin_unlock_irqrestore(&bufferlock, flags); | |
330 | wake_up_interruptible(&dasd_eer_read_wait_queue); | |
331 | } | |
332 | ||
333 | /* | |
334 | * This function writes a DASD_EER_STATECHANGE trigger. | |
335 | */ | |
336 | static void dasd_eer_write_snss_trigger(struct dasd_device *device, | |
337 | struct dasd_ccw_req *cqr, | |
338 | int trigger) | |
339 | { | |
340 | int data_size; | |
341 | int snss_rc; | |
342 | struct timeval tv; | |
343 | struct dasd_eer_header header; | |
344 | unsigned long flags; | |
345 | struct eerbuffer *eerb; | |
346 | ||
8e09f215 | 347 | snss_rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO; |
20c64468 SW |
348 | if (snss_rc) |
349 | data_size = 0; | |
350 | else | |
351 | data_size = SNSS_DATA_SIZE; | |
352 | ||
353 | header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ | |
354 | header.trigger = DASD_EER_STATECHANGE; | |
355 | do_gettimeofday(&tv); | |
356 | header.tv_sec = tv.tv_sec; | |
357 | header.tv_usec = tv.tv_usec; | |
2a0217d5 KS |
358 | strncpy(header.busid, dev_name(&device->cdev->dev), |
359 | DASD_EER_BUSID_SIZE); | |
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360 | |
361 | spin_lock_irqsave(&bufferlock, flags); | |
362 | list_for_each_entry(eerb, &bufferlist, list) { | |
363 | dasd_eer_start_record(eerb, header.total_size); | |
364 | dasd_eer_write_buffer(eerb, (char *) &header , sizeof(header)); | |
365 | if (!snss_rc) | |
366 | dasd_eer_write_buffer(eerb, cqr->data, SNSS_DATA_SIZE); | |
367 | dasd_eer_write_buffer(eerb, "EOR", 4); | |
368 | } | |
369 | spin_unlock_irqrestore(&bufferlock, flags); | |
370 | wake_up_interruptible(&dasd_eer_read_wait_queue); | |
371 | } | |
372 | ||
373 | /* | |
374 | * This function is called for all triggers. It calls the appropriate | |
375 | * function that writes the actual trigger records. | |
376 | */ | |
377 | void dasd_eer_write(struct dasd_device *device, struct dasd_ccw_req *cqr, | |
378 | unsigned int id) | |
379 | { | |
380 | if (!device->eer_cqr) | |
381 | return; | |
382 | switch (id) { | |
383 | case DASD_EER_FATALERROR: | |
384 | case DASD_EER_PPRCSUSPEND: | |
385 | dasd_eer_write_standard_trigger(device, cqr, id); | |
386 | break; | |
387 | case DASD_EER_NOPATH: | |
388 | dasd_eer_write_standard_trigger(device, NULL, id); | |
389 | break; | |
390 | case DASD_EER_STATECHANGE: | |
391 | dasd_eer_write_snss_trigger(device, cqr, id); | |
392 | break; | |
393 | default: /* unknown trigger, so we write it without any sense data */ | |
394 | dasd_eer_write_standard_trigger(device, NULL, id); | |
395 | break; | |
396 | } | |
397 | } | |
398 | EXPORT_SYMBOL(dasd_eer_write); | |
399 | ||
400 | /* | |
401 | * Start a sense subsystem status request. | |
402 | * Needs to be called with the device held. | |
403 | */ | |
404 | void dasd_eer_snss(struct dasd_device *device) | |
405 | { | |
406 | struct dasd_ccw_req *cqr; | |
407 | ||
408 | cqr = device->eer_cqr; | |
409 | if (!cqr) /* Device not eer enabled. */ | |
410 | return; | |
411 | if (test_and_set_bit(DASD_FLAG_EER_IN_USE, &device->flags)) { | |
412 | /* Sense subsystem status request in use. */ | |
413 | set_bit(DASD_FLAG_EER_SNSS, &device->flags); | |
414 | return; | |
415 | } | |
8e09f215 | 416 | /* cdev is already locked, can't use dasd_add_request_head */ |
20c64468 SW |
417 | clear_bit(DASD_FLAG_EER_SNSS, &device->flags); |
418 | cqr->status = DASD_CQR_QUEUED; | |
8e09f215 SW |
419 | list_add(&cqr->devlist, &device->ccw_queue); |
420 | dasd_schedule_device_bh(device); | |
20c64468 SW |
421 | } |
422 | ||
423 | /* | |
424 | * Callback function for use with sense subsystem status request. | |
425 | */ | |
426 | static void dasd_eer_snss_cb(struct dasd_ccw_req *cqr, void *data) | |
427 | { | |
8e09f215 | 428 | struct dasd_device *device = cqr->startdev; |
20c64468 SW |
429 | unsigned long flags; |
430 | ||
431 | dasd_eer_write(device, cqr, DASD_EER_STATECHANGE); | |
432 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); | |
433 | if (device->eer_cqr == cqr) { | |
434 | clear_bit(DASD_FLAG_EER_IN_USE, &device->flags); | |
435 | if (test_bit(DASD_FLAG_EER_SNSS, &device->flags)) | |
436 | /* Another SNSS has been requested in the meantime. */ | |
437 | dasd_eer_snss(device); | |
438 | cqr = NULL; | |
439 | } | |
440 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); | |
441 | if (cqr) | |
442 | /* | |
443 | * Extended error recovery has been switched off while | |
444 | * the SNSS request was running. It could even have | |
445 | * been switched off and on again in which case there | |
446 | * is a new ccw in device->eer_cqr. Free the "old" | |
447 | * snss request now. | |
448 | */ | |
449 | dasd_kfree_request(cqr, device); | |
450 | } | |
451 | ||
452 | /* | |
453 | * Enable error reporting on a given device. | |
454 | */ | |
455 | int dasd_eer_enable(struct dasd_device *device) | |
456 | { | |
457 | struct dasd_ccw_req *cqr; | |
458 | unsigned long flags; | |
f3eb5384 | 459 | struct ccw1 *ccw; |
20c64468 SW |
460 | |
461 | if (device->eer_cqr) | |
462 | return 0; | |
463 | ||
464 | if (!device->discipline || strcmp(device->discipline->name, "ECKD")) | |
465 | return -EPERM; /* FIXME: -EMEDIUMTYPE ? */ | |
466 | ||
68b781fe | 467 | cqr = dasd_kmalloc_request(DASD_ECKD_MAGIC, 1 /* SNSS */, |
20c64468 | 468 | SNSS_DATA_SIZE, device); |
0983e568 | 469 | if (IS_ERR(cqr)) |
20c64468 SW |
470 | return -ENOMEM; |
471 | ||
8e09f215 | 472 | cqr->startdev = device; |
20c64468 SW |
473 | cqr->retries = 255; |
474 | cqr->expires = 10 * HZ; | |
046f3e82 | 475 | clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags); |
5a27e60d | 476 | set_bit(DASD_CQR_ALLOW_SLOCK, &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 | 483 | |
1aae0560 | 484 | cqr->buildclk = get_tod_clock(); |
20c64468 SW |
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 | } |