1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Character device driver for extended error reporting. |
4 | * |
5 | * Copyright IBM Corp. 2005 |
6 | * extended error reporting for DASD ECKD devices |
7 | * Author(s): Stefan Weinhuber <wein@de.ibm.com> |
8 | */ |
9 | |
10 | #define KMSG_COMPONENT "dasd-eckd" |
11 | |
12 | #include <linux/init.h> |
13 | #include <linux/fs.h> |
14 | #include <linux/kernel.h> |
15 | #include <linux/miscdevice.h> |
16 | #include <linux/module.h> |
17 | #include <linux/moduleparam.h> |
18 | #include <linux/device.h> |
19 | #include <linux/poll.h> |
20 | #include <linux/mutex.h> |
21 | #include <linux/err.h> |
22 | #include <linux/slab.h> |
23 | |
24 | #include <linux/uaccess.h> |
25 | #include <linux/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 "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); |
97 | static DEFINE_SPINLOCK(bufferlock); |
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, data: (char *) &tailcount, |
202 | count: sizeof(tailcount)); |
203 | eerb->tail += tailcount; |
204 | if (eerb->tail >= eerb->buffersize) |
205 | eerb->tail -= eerb->buffersize; |
206 | } |
207 | dasd_eer_write_buffer(eerb, data: (char*) &count, 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, no_pages: 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 { |
279 | __u32 ; |
280 | __u32 ; |
281 | __u64 ; |
282 | __u64 ; |
283 | char [DASD_EER_BUSID_SIZE]; |
284 | } __attribute__ ((packed)); |
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 timespec64 ts; |
300 | struct dasd_eer_header ; |
301 | unsigned long flags; |
302 | struct eerbuffer *eerb; |
303 | char *sense; |
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) |
308 | if (dasd_get_sense(&temp_cqr->irb)) |
309 | data_size += 32; |
310 | |
311 | header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ |
312 | header.trigger = trigger; |
313 | ktime_get_real_ts64(tv: &ts); |
314 | header.tv_sec = ts.tv_sec; |
315 | header.tv_usec = ts.tv_nsec / NSEC_PER_USEC; |
316 | strscpy(header.busid, dev_name(dev: &device->cdev->dev), |
317 | DASD_EER_BUSID_SIZE); |
318 | |
319 | spin_lock_irqsave(&bufferlock, flags); |
320 | list_for_each_entry(eerb, &bufferlist, list) { |
321 | dasd_eer_start_record(eerb, count: header.total_size); |
322 | dasd_eer_write_buffer(eerb, data: (char *) &header, count: sizeof(header)); |
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, data: sense, count: 32); |
327 | } |
328 | dasd_eer_write_buffer(eerb, data: "EOR" , count: 4); |
329 | } |
330 | spin_unlock_irqrestore(lock: &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 timespec64 ts; |
344 | struct dasd_eer_header ; |
345 | unsigned long flags; |
346 | struct eerbuffer *eerb; |
347 | |
348 | snss_rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO; |
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 | ktime_get_real_ts64(tv: &ts); |
357 | header.tv_sec = ts.tv_sec; |
358 | header.tv_usec = ts.tv_nsec / NSEC_PER_USEC; |
359 | strscpy(header.busid, dev_name(dev: &device->cdev->dev), |
360 | DASD_EER_BUSID_SIZE); |
361 | |
362 | spin_lock_irqsave(&bufferlock, flags); |
363 | list_for_each_entry(eerb, &bufferlist, list) { |
364 | dasd_eer_start_record(eerb, count: header.total_size); |
365 | dasd_eer_write_buffer(eerb, data: (char *) &header , count: sizeof(header)); |
366 | if (!snss_rc) |
367 | dasd_eer_write_buffer(eerb, data: cqr->data, SNSS_DATA_SIZE); |
368 | dasd_eer_write_buffer(eerb, data: "EOR" , count: 4); |
369 | } |
370 | spin_unlock_irqrestore(lock: &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 | case DASD_EER_NOSPC: |
390 | case DASD_EER_AUTOQUIESCE: |
391 | dasd_eer_write_standard_trigger(device, NULL, id); |
392 | break; |
393 | case DASD_EER_STATECHANGE: |
394 | dasd_eer_write_snss_trigger(device, cqr, id); |
395 | break; |
396 | default: /* unknown trigger, so we write it without any sense data */ |
397 | dasd_eer_write_standard_trigger(device, NULL, id); |
398 | break; |
399 | } |
400 | } |
401 | EXPORT_SYMBOL(dasd_eer_write); |
402 | |
403 | /* |
404 | * Start a sense subsystem status request. |
405 | * Needs to be called with the device held. |
406 | */ |
407 | void dasd_eer_snss(struct dasd_device *device) |
408 | { |
409 | struct dasd_ccw_req *cqr; |
410 | |
411 | cqr = device->eer_cqr; |
412 | if (!cqr) /* Device not eer enabled. */ |
413 | return; |
414 | if (test_and_set_bit(DASD_FLAG_EER_IN_USE, &device->flags)) { |
415 | /* Sense subsystem status request in use. */ |
416 | set_bit(DASD_FLAG_EER_SNSS, &device->flags); |
417 | return; |
418 | } |
419 | /* cdev is already locked, can't use dasd_add_request_head */ |
420 | clear_bit(DASD_FLAG_EER_SNSS, &device->flags); |
421 | cqr->status = DASD_CQR_QUEUED; |
422 | list_add(&cqr->devlist, &device->ccw_queue); |
423 | dasd_schedule_device_bh(device); |
424 | } |
425 | |
426 | /* |
427 | * Callback function for use with sense subsystem status request. |
428 | */ |
429 | static void dasd_eer_snss_cb(struct dasd_ccw_req *cqr, void *data) |
430 | { |
431 | struct dasd_device *device = cqr->startdev; |
432 | unsigned long flags; |
433 | |
434 | dasd_eer_write(device, cqr, DASD_EER_STATECHANGE); |
435 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); |
436 | if (device->eer_cqr == cqr) { |
437 | clear_bit(DASD_FLAG_EER_IN_USE, addr: &device->flags); |
438 | if (test_bit(DASD_FLAG_EER_SNSS, &device->flags)) |
439 | /* Another SNSS has been requested in the meantime. */ |
440 | dasd_eer_snss(device); |
441 | cqr = NULL; |
442 | } |
443 | spin_unlock_irqrestore(lock: get_ccwdev_lock(device->cdev), flags); |
444 | if (cqr) |
445 | /* |
446 | * Extended error recovery has been switched off while |
447 | * the SNSS request was running. It could even have |
448 | * been switched off and on again in which case there |
449 | * is a new ccw in device->eer_cqr. Free the "old" |
450 | * snss request now. |
451 | */ |
452 | dasd_sfree_request(cqr, device); |
453 | } |
454 | |
455 | /* |
456 | * Enable error reporting on a given device. |
457 | */ |
458 | int dasd_eer_enable(struct dasd_device *device) |
459 | { |
460 | struct dasd_ccw_req *cqr = NULL; |
461 | unsigned long flags; |
462 | struct ccw1 *ccw; |
463 | int rc = 0; |
464 | |
465 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); |
466 | if (device->eer_cqr) |
467 | goto out; |
468 | else if (!device->discipline || |
469 | strcmp(device->discipline->name, "ECKD" )) |
470 | rc = -EMEDIUMTYPE; |
471 | else if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) |
472 | rc = -EBUSY; |
473 | |
474 | if (rc) |
475 | goto out; |
476 | |
477 | cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* SNSS */, |
478 | SNSS_DATA_SIZE, device, NULL); |
479 | if (IS_ERR(cqr)) { |
480 | rc = -ENOMEM; |
481 | cqr = NULL; |
482 | goto out; |
483 | } |
484 | |
485 | cqr->startdev = device; |
486 | cqr->retries = 255; |
487 | cqr->expires = 10 * HZ; |
488 | clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags); |
489 | set_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags); |
490 | |
491 | ccw = cqr->cpaddr; |
492 | ccw->cmd_code = DASD_ECKD_CCW_SNSS; |
493 | ccw->count = SNSS_DATA_SIZE; |
494 | ccw->flags = 0; |
495 | ccw->cda = (__u32)virt_to_phys(cqr->data); |
496 | |
497 | cqr->buildclk = get_tod_clock(); |
498 | cqr->status = DASD_CQR_FILLED; |
499 | cqr->callback = dasd_eer_snss_cb; |
500 | |
501 | if (!device->eer_cqr) { |
502 | device->eer_cqr = cqr; |
503 | cqr = NULL; |
504 | } |
505 | |
506 | out: |
507 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); |
508 | |
509 | if (cqr) |
510 | dasd_sfree_request(cqr, device); |
511 | |
512 | return rc; |
513 | } |
514 | |
515 | /* |
516 | * Disable error reporting on a given device. |
517 | */ |
518 | void dasd_eer_disable(struct dasd_device *device) |
519 | { |
520 | struct dasd_ccw_req *cqr; |
521 | unsigned long flags; |
522 | int in_use; |
523 | |
524 | if (!device->eer_cqr) |
525 | return; |
526 | spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); |
527 | cqr = device->eer_cqr; |
528 | device->eer_cqr = NULL; |
529 | clear_bit(DASD_FLAG_EER_SNSS, &device->flags); |
530 | in_use = test_and_clear_bit(DASD_FLAG_EER_IN_USE, &device->flags); |
531 | spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); |
532 | if (cqr && !in_use) |
533 | dasd_sfree_request(cqr, device); |
534 | } |
535 | |
536 | /* |
537 | * SECTION: the device operations |
538 | */ |
539 | |
540 | /* |
541 | * On the one side we need a lock to access our internal buffer, on the |
542 | * other side a copy_to_user can sleep. So we need to copy the data we have |
543 | * to transfer in a readbuffer, which is protected by the readbuffer_mutex. |
544 | */ |
545 | static char readbuffer[PAGE_SIZE]; |
546 | static DEFINE_MUTEX(readbuffer_mutex); |
547 | |
548 | static int dasd_eer_open(struct inode *inp, struct file *filp) |
549 | { |
550 | struct eerbuffer *eerb; |
551 | unsigned long flags; |
552 | |
553 | eerb = kzalloc(size: sizeof(struct eerbuffer), GFP_KERNEL); |
554 | if (!eerb) |
555 | return -ENOMEM; |
556 | eerb->buffer_page_count = eer_pages; |
557 | if (eerb->buffer_page_count < 1 || |
558 | eerb->buffer_page_count > INT_MAX / PAGE_SIZE) { |
559 | kfree(objp: eerb); |
560 | DBF_EVENT(DBF_WARNING, "can't open device since module " |
561 | "parameter eer_pages is smaller than 1 or" |
562 | " bigger than %d" , (int)(INT_MAX / PAGE_SIZE)); |
563 | return -EINVAL; |
564 | } |
565 | eerb->buffersize = eerb->buffer_page_count * PAGE_SIZE; |
566 | eerb->buffer = kmalloc_array(n: eerb->buffer_page_count, size: sizeof(char *), |
567 | GFP_KERNEL); |
568 | if (!eerb->buffer) { |
569 | kfree(objp: eerb); |
570 | return -ENOMEM; |
571 | } |
572 | if (dasd_eer_allocate_buffer_pages(buf: eerb->buffer, |
573 | no_pages: eerb->buffer_page_count)) { |
574 | kfree(objp: eerb->buffer); |
575 | kfree(objp: eerb); |
576 | return -ENOMEM; |
577 | } |
578 | filp->private_data = eerb; |
579 | spin_lock_irqsave(&bufferlock, flags); |
580 | list_add(new: &eerb->list, head: &bufferlist); |
581 | spin_unlock_irqrestore(lock: &bufferlock, flags); |
582 | |
583 | return nonseekable_open(inode: inp,filp); |
584 | } |
585 | |
586 | static int dasd_eer_close(struct inode *inp, struct file *filp) |
587 | { |
588 | struct eerbuffer *eerb; |
589 | unsigned long flags; |
590 | |
591 | eerb = (struct eerbuffer *) filp->private_data; |
592 | spin_lock_irqsave(&bufferlock, flags); |
593 | list_del(entry: &eerb->list); |
594 | spin_unlock_irqrestore(lock: &bufferlock, flags); |
595 | dasd_eer_free_buffer_pages(buf: eerb->buffer, no_pages: eerb->buffer_page_count); |
596 | kfree(objp: eerb->buffer); |
597 | kfree(objp: eerb); |
598 | |
599 | return 0; |
600 | } |
601 | |
602 | static ssize_t dasd_eer_read(struct file *filp, char __user *buf, |
603 | size_t count, loff_t *ppos) |
604 | { |
605 | int tc,rc; |
606 | int tailcount,effective_count; |
607 | unsigned long flags; |
608 | struct eerbuffer *eerb; |
609 | |
610 | eerb = (struct eerbuffer *) filp->private_data; |
611 | if (mutex_lock_interruptible(&readbuffer_mutex)) |
612 | return -ERESTARTSYS; |
613 | |
614 | spin_lock_irqsave(&bufferlock, flags); |
615 | |
616 | if (eerb->residual < 0) { /* the remainder of this record */ |
617 | /* has been deleted */ |
618 | eerb->residual = 0; |
619 | spin_unlock_irqrestore(lock: &bufferlock, flags); |
620 | mutex_unlock(lock: &readbuffer_mutex); |
621 | return -EIO; |
622 | } else if (eerb->residual > 0) { |
623 | /* OK we still have a second half of a record to deliver */ |
624 | effective_count = min(eerb->residual, (int) count); |
625 | eerb->residual -= effective_count; |
626 | } else { |
627 | tc = 0; |
628 | while (!tc) { |
629 | tc = dasd_eer_read_buffer(eerb, data: (char *) &tailcount, |
630 | count: sizeof(tailcount)); |
631 | if (!tc) { |
632 | /* no data available */ |
633 | spin_unlock_irqrestore(lock: &bufferlock, flags); |
634 | mutex_unlock(lock: &readbuffer_mutex); |
635 | if (filp->f_flags & O_NONBLOCK) |
636 | return -EAGAIN; |
637 | rc = wait_event_interruptible( |
638 | dasd_eer_read_wait_queue, |
639 | eerb->head != eerb->tail); |
640 | if (rc) |
641 | return rc; |
642 | if (mutex_lock_interruptible(&readbuffer_mutex)) |
643 | return -ERESTARTSYS; |
644 | spin_lock_irqsave(&bufferlock, flags); |
645 | } |
646 | } |
647 | WARN_ON(tc != sizeof(tailcount)); |
648 | effective_count = min(tailcount,(int)count); |
649 | eerb->residual = tailcount - effective_count; |
650 | } |
651 | |
652 | tc = dasd_eer_read_buffer(eerb, data: readbuffer, count: effective_count); |
653 | WARN_ON(tc != effective_count); |
654 | |
655 | spin_unlock_irqrestore(lock: &bufferlock, flags); |
656 | |
657 | if (copy_to_user(to: buf, from: readbuffer, n: effective_count)) { |
658 | mutex_unlock(lock: &readbuffer_mutex); |
659 | return -EFAULT; |
660 | } |
661 | |
662 | mutex_unlock(lock: &readbuffer_mutex); |
663 | return effective_count; |
664 | } |
665 | |
666 | static __poll_t dasd_eer_poll(struct file *filp, poll_table *ptable) |
667 | { |
668 | __poll_t mask; |
669 | unsigned long flags; |
670 | struct eerbuffer *eerb; |
671 | |
672 | eerb = (struct eerbuffer *) filp->private_data; |
673 | poll_wait(filp, wait_address: &dasd_eer_read_wait_queue, p: ptable); |
674 | spin_lock_irqsave(&bufferlock, flags); |
675 | if (eerb->head != eerb->tail) |
676 | mask = EPOLLIN | EPOLLRDNORM ; |
677 | else |
678 | mask = 0; |
679 | spin_unlock_irqrestore(lock: &bufferlock, flags); |
680 | return mask; |
681 | } |
682 | |
683 | static const struct file_operations dasd_eer_fops = { |
684 | .open = &dasd_eer_open, |
685 | .release = &dasd_eer_close, |
686 | .read = &dasd_eer_read, |
687 | .poll = &dasd_eer_poll, |
688 | .owner = THIS_MODULE, |
689 | .llseek = noop_llseek, |
690 | }; |
691 | |
692 | static struct miscdevice *dasd_eer_dev = NULL; |
693 | |
694 | int __init dasd_eer_init(void) |
695 | { |
696 | int rc; |
697 | |
698 | dasd_eer_dev = kzalloc(sizeof(*dasd_eer_dev), GFP_KERNEL); |
699 | if (!dasd_eer_dev) |
700 | return -ENOMEM; |
701 | |
702 | dasd_eer_dev->minor = MISC_DYNAMIC_MINOR; |
703 | dasd_eer_dev->name = "dasd_eer" ; |
704 | dasd_eer_dev->fops = &dasd_eer_fops; |
705 | |
706 | rc = misc_register(dasd_eer_dev); |
707 | if (rc) { |
708 | kfree(dasd_eer_dev); |
709 | dasd_eer_dev = NULL; |
710 | DBF_EVENT(DBF_ERR, "%s" , "dasd_eer_init could not " |
711 | "register misc device" ); |
712 | return rc; |
713 | } |
714 | |
715 | return 0; |
716 | } |
717 | |
718 | void dasd_eer_exit(void) |
719 | { |
720 | if (dasd_eer_dev) { |
721 | misc_deregister(dasd_eer_dev); |
722 | kfree(dasd_eer_dev); |
723 | dasd_eer_dev = NULL; |
724 | } |
725 | } |
726 | |