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authorBorislav Petkov <petkovbb@googlemail.com>2008-02-05 20:57:53 -0500
committerBartlomiej Zolnierkiewicz <bzolnier@gmail.com>2008-02-05 20:57:53 -0500
commit3c98bf347d95cf9c43104db2fda848d0c7decebd (patch)
treef2f5b4522c894026137cf8849465572747884414 /drivers
parent8d06bfadb44bfec067603fbc8ee2faced3b13ad9 (diff)
ide-tape: cleanup and fix comments
Also, remove redundant ones and cleanup whitespace. Bart: - minor fixups Signed-off-by: Borislav Petkov <petkovbb@gmail.com> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/ide/ide-tape.c681
1 files changed, 271 insertions, 410 deletions
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index bdf02fcc1a25..d8b02fb0284c 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -75,37 +75,34 @@ enum {
75 75
76 76
77/* 77/*
78 * Pipelined mode parameters. 78 * Pipelined mode parameters.
79 * 79 *
80 * We try to use the minimum number of stages which is enough to 80 * We try to use the minimum number of stages which is enough to keep the tape
81 * keep the tape constantly streaming. To accomplish that, we implement 81 * constantly streaming. To accomplish that, we implement a feedback loop around
82 * a feedback loop around the maximum number of stages: 82 * the maximum number of stages:
83 * 83 *
84 * We start from MIN maximum stages (we will not even use MIN stages 84 * We start from MIN maximum stages (we will not even use MIN stages if we don't
85 * if we don't need them), increment it by RATE*(MAX-MIN) 85 * need them), increment it by RATE*(MAX-MIN) whenever we sense that the
86 * whenever we sense that the pipeline is empty, until we reach 86 * pipeline is empty, until we reach the optimum value or until we reach MAX.
87 * the optimum value or until we reach MAX.
88 * 87 *
89 * Setting the following parameter to 0 is illegal: the pipelined mode 88 * Setting the following parameter to 0 is illegal: the pipelined mode cannot be
90 * cannot be disabled (idetape_calculate_speeds() divides by 89 * disabled (idetape_calculate_speeds() divides by tape->max_stages.)
91 * tape->max_stages.)
92 */ 90 */
93#define IDETAPE_MIN_PIPELINE_STAGES 1 91#define IDETAPE_MIN_PIPELINE_STAGES 1
94#define IDETAPE_MAX_PIPELINE_STAGES 400 92#define IDETAPE_MAX_PIPELINE_STAGES 400
95#define IDETAPE_INCREASE_STAGES_RATE 20 93#define IDETAPE_INCREASE_STAGES_RATE 20
96 94
97/* 95/*
98 * After each failed packet command we issue a request sense command 96 * After each failed packet command we issue a request sense command and retry
99 * and retry the packet command IDETAPE_MAX_PC_RETRIES times. 97 * the packet command IDETAPE_MAX_PC_RETRIES times.
100 * 98 *
101 * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries. 99 * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
102 */ 100 */
103#define IDETAPE_MAX_PC_RETRIES 3 101#define IDETAPE_MAX_PC_RETRIES 3
104 102
105/* 103/*
106 * With each packet command, we allocate a buffer of 104 * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
107 * IDETAPE_PC_BUFFER_SIZE bytes. This is used for several packet 105 * bytes. This is used for several packet commands (Not for READ/WRITE commands)
108 * commands (Not for READ/WRITE commands).
109 */ 106 */
110#define IDETAPE_PC_BUFFER_SIZE 256 107#define IDETAPE_PC_BUFFER_SIZE 256
111 108
@@ -124,48 +121,39 @@ enum {
124#define IDETAPE_WAIT_CMD (900*HZ) 121#define IDETAPE_WAIT_CMD (900*HZ)
125 122
126/* 123/*
127 * The following parameter is used to select the point in the internal 124 * The following parameter is used to select the point in the internal tape fifo
128 * tape fifo in which we will start to refill the buffer. Decreasing 125 * in which we will start to refill the buffer. Decreasing the following
129 * the following parameter will improve the system's latency and 126 * parameter will improve the system's latency and interactive response, while
130 * interactive response, while using a high value might improve system 127 * using a high value might improve system throughput.
131 * throughput.
132 */ 128 */
133#define IDETAPE_FIFO_THRESHOLD 2 129#define IDETAPE_FIFO_THRESHOLD 2
134 130
135/* 131/*
136 * DSC polling parameters. 132 * DSC polling parameters.
137 * 133 *
138 * Polling for DSC (a single bit in the status register) is a very 134 * Polling for DSC (a single bit in the status register) is a very important
139 * important function in ide-tape. There are two cases in which we 135 * function in ide-tape. There are two cases in which we poll for DSC:
140 * poll for DSC:
141 * 136 *
142 * 1. Before a read/write packet command, to ensure that we 137 * 1. Before a read/write packet command, to ensure that we can transfer data
143 * can transfer data from/to the tape's data buffers, without 138 * from/to the tape's data buffers, without causing an actual media access.
144 * causing an actual media access. In case the tape is not 139 * In case the tape is not ready yet, we take out our request from the device
145 * ready yet, we take out our request from the device 140 * request queue, so that ide.c could service requests from the other device
146 * request queue, so that ide.c will service requests from 141 * on the same interface in the meantime.
147 * the other device on the same interface meanwhile.
148 * 142 *
149 * 2. After the successful initialization of a "media access 143 * 2. After the successful initialization of a "media access packet command",
150 * packet command", which is a command which can take a long 144 * which is a command that can take a long time to complete (the interval can
151 * time to complete (it can be several seconds or even an hour). 145 * range from several seconds to even an hour). Again, we postpone our request
146 * in the middle to free the bus for the other device. The polling frequency
147 * here should be lower than the read/write frequency since those media access
148 * commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
149 * (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
150 * (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
152 * 151 *
153 * Again, we postpone our request in the middle to free the bus 152 * We also set a timeout for the timer, in case something goes wrong. The
154 * for the other device. The polling frequency here should be 153 * timeout should be longer then the maximum execution time of a tape operation.
155 * lower than the read/write frequency since those media access
156 * commands are slow. We start from a "fast" frequency -
157 * IDETAPE_DSC_MA_FAST (one second), and if we don't receive DSC
158 * after IDETAPE_DSC_MA_THRESHOLD (5 minutes), we switch it to a
159 * lower frequency - IDETAPE_DSC_MA_SLOW (1 minute).
160 *
161 * We also set a timeout for the timer, in case something goes wrong.
162 * The timeout should be longer then the maximum execution time of a
163 * tape operation.
164 */
165
166/*
167 * DSC timings.
168 */ 154 */
155
156/* DSC timings. */
169#define IDETAPE_DSC_RW_MIN 5*HZ/100 /* 50 msec */ 157#define IDETAPE_DSC_RW_MIN 5*HZ/100 /* 50 msec */
170#define IDETAPE_DSC_RW_MAX 40*HZ/100 /* 400 msec */ 158#define IDETAPE_DSC_RW_MAX 40*HZ/100 /* 400 msec */
171#define IDETAPE_DSC_RW_TIMEOUT 2*60*HZ /* 2 minutes */ 159#define IDETAPE_DSC_RW_TIMEOUT 2*60*HZ /* 2 minutes */
@@ -176,15 +164,9 @@ enum {
176 164
177/*************************** End of tunable parameters ***********************/ 165/*************************** End of tunable parameters ***********************/
178 166
179/* 167/* Read/Write error simulation */
180 * Read/Write error simulation
181 */
182#define SIMULATE_ERRORS 0 168#define SIMULATE_ERRORS 0
183 169
184/*
185 * For general magnetic tape device compatibility.
186 */
187
188/* tape directions */ 170/* tape directions */
189enum { 171enum {
190 IDETAPE_DIR_NONE = (1 << 0), 172 IDETAPE_DIR_NONE = (1 << 0),
@@ -199,24 +181,32 @@ struct idetape_bh {
199 char *b_data; 181 char *b_data;
200}; 182};
201 183
202/*
203 * Our view of a packet command.
204 */
205typedef struct idetape_packet_command_s { 184typedef struct idetape_packet_command_s {
206 u8 c[12]; /* Actual packet bytes */ 185 /* Actual packet bytes */
207 int retries; /* On each retry, we increment retries */ 186 u8 c[12];
208 int error; /* Error code */ 187 /* On each retry, we increment retries */
209 int request_transfer; /* Bytes to transfer */ 188 int retries;
210 int actually_transferred; /* Bytes actually transferred */ 189 /* Error code */
211 int buffer_size; /* Size of our data buffer */ 190 int error;
191 /* Bytes to transfer */
192 int request_transfer;
193 /* Bytes actually transferred */
194 int actually_transferred;
195 /* Size of our data buffer */
196 int buffer_size;
212 struct idetape_bh *bh; 197 struct idetape_bh *bh;
213 char *b_data; 198 char *b_data;
214 int b_count; 199 int b_count;
215 u8 *buffer; /* Data buffer */ 200 /* Data buffer */
216 u8 *current_position; /* Pointer into the above buffer */ 201 u8 *buffer;
217 ide_startstop_t (*callback) (ide_drive_t *); /* Called when this packet command is completed */ 202 /* Pointer into the above buffer */
218 u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE]; /* Temporary buffer */ 203 u8 *current_position;
219 unsigned long flags; /* Status/Action bit flags: long for set_bit */ 204 /* Called when this packet command is completed */
205 ide_startstop_t (*callback) (ide_drive_t *);
206 /* Temporary buffer */
207 u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE];
208 /* Status/Action bit flags: long for set_bit */
209 unsigned long flags;
220} idetape_pc_t; 210} idetape_pc_t;
221 211
222/* 212/*
@@ -235,9 +225,7 @@ typedef struct idetape_packet_command_s {
235/* Data direction */ 225/* Data direction */
236#define PC_WRITING 5 226#define PC_WRITING 5
237 227
238/* 228/* A pipeline stage. */
239 * A pipeline stage.
240 */
241typedef struct idetape_stage_s { 229typedef struct idetape_stage_s {
242 struct request rq; /* The corresponding request */ 230 struct request rq; /* The corresponding request */
243 struct idetape_bh *bh; /* The data buffers */ 231 struct idetape_bh *bh; /* The data buffers */
@@ -245,9 +233,8 @@ typedef struct idetape_stage_s {
245} idetape_stage_t; 233} idetape_stage_t;
246 234
247/* 235/*
248 * Most of our global data which we need to save even as we leave the 236 * Most of our global data which we need to save even as we leave the driver due
249 * driver due to an interrupt or a timer event is stored in a variable 237 * to an interrupt or a timer event is stored in the struct defined below.
250 * of type idetape_tape_t, defined below.
251 */ 238 */
252typedef struct ide_tape_obj { 239typedef struct ide_tape_obj {
253 ide_drive_t *drive; 240 ide_drive_t *drive;
@@ -283,15 +270,14 @@ typedef struct ide_tape_obj {
283 int rq_stack_index; 270 int rq_stack_index;
284 271
285 /* 272 /*
286 * DSC polling variables. 273 * DSC polling variables.
287 * 274 *
288 * While polling for DSC we use postponed_rq to postpone the 275 * While polling for DSC we use postponed_rq to postpone the current
289 * current request so that ide.c will be able to service 276 * request so that ide.c will be able to service pending requests on the
290 * pending requests on the other device. Note that at most 277 * other device. Note that at most we will have only one DSC (usually
291 * we will have only one DSC (usually data transfer) request 278 * data transfer) request in the device request queue. Additional
292 * in the device request queue. Additional requests can be 279 * requests can be queued in our internal pipeline, but they will be
293 * queued in our internal pipeline, but they will be visible 280 * visible to ide.c only one at a time.
294 * to ide.c only one at a time.
295 */ 281 */
296 struct request *postponed_rq; 282 struct request *postponed_rq;
297 /* The time in which we started polling for DSC */ 283 /* The time in which we started polling for DSC */
@@ -303,21 +289,15 @@ typedef struct ide_tape_obj {
303 unsigned long dsc_poll_freq; 289 unsigned long dsc_poll_freq;
304 unsigned long dsc_timeout; 290 unsigned long dsc_timeout;
305 291
306 /* 292 /* Read position information */
307 * Read position information
308 */
309 u8 partition; 293 u8 partition;
310 /* Current block */ 294 /* Current block */
311 unsigned int first_frame; 295 unsigned int first_frame;
312 296
313 /* 297 /* Last error information */
314 * Last error information
315 */
316 u8 sense_key, asc, ascq; 298 u8 sense_key, asc, ascq;
317 299
318 /* 300 /* Character device operation */
319 * Character device operation
320 */
321 unsigned int minor; 301 unsigned int minor;
322 /* device name */ 302 /* device name */
323 char name[4]; 303 char name[4];
@@ -332,33 +312,30 @@ typedef struct ide_tape_obj {
332 u8 caps[20]; 312 u8 caps[20];
333 313
334 /* 314 /*
335 * Active data transfer request parameters. 315 * Active data transfer request parameters.
336 *
337 * At most, there is only one ide-tape originated data transfer
338 * request in the device request queue. This allows ide.c to
339 * easily service requests from the other device when we
340 * postpone our active request. In the pipelined operation
341 * mode, we use our internal pipeline structure to hold
342 * more data requests.
343 * 316 *
344 * The data buffer size is chosen based on the tape's 317 * At most, there is only one ide-tape originated data transfer request
345 * recommendation. 318 * in the device request queue. This allows ide.c to easily service
319 * requests from the other device when we postpone our active request.
320 * In the pipelined operation mode, we use our internal pipeline
321 * structure to hold more data requests. The data buffer size is chosen
322 * based on the tape's recommendation.
346 */ 323 */
347 /* Ptr to the request which is waiting in the device request queue */ 324 /* ptr to the request which is waiting in the device request queue */
348 struct request *active_data_rq; 325 struct request *active_data_rq;
349 /* Data buffer size (chosen based on the tape's recommendation */ 326 /* Data buffer size chosen based on the tape's recommendation */
350 int stage_size; 327 int stage_size;
351 idetape_stage_t *merge_stage; 328 idetape_stage_t *merge_stage;
352 int merge_stage_size; 329 int merge_stage_size;
353 struct idetape_bh *bh; 330 struct idetape_bh *bh;
354 char *b_data; 331 char *b_data;
355 int b_count; 332 int b_count;
356 333
357 /* 334 /*
358 * Pipeline parameters. 335 * Pipeline parameters.
359 * 336 *
360 * To accomplish non-pipelined mode, we simply set the following 337 * To accomplish non-pipelined mode, we simply set the following
361 * variables to zero (or NULL, where appropriate). 338 * variables to zero (or NULL, where appropriate).
362 */ 339 */
363 /* Number of currently used stages */ 340 /* Number of currently used stages */
364 int nr_stages; 341 int nr_stages;
@@ -385,9 +362,7 @@ typedef struct ide_tape_obj {
385 /* protects the ide-tape queue */ 362 /* protects the ide-tape queue */
386 spinlock_t lock; 363 spinlock_t lock;
387 364
388 /* 365 /* Measures average tape speed */
389 * Measures average tape speed
390 */
391 unsigned long avg_time; 366 unsigned long avg_time;
392 int avg_size; 367 int avg_size;
393 int avg_speed; 368 int avg_speed;
@@ -400,11 +375,9 @@ typedef struct ide_tape_obj {
400 char write_prot; 375 char write_prot;
401 376
402 /* 377 /*
403 * Limit the number of times a request can 378 * Limit the number of times a request can be postponed, to avoid an
404 * be postponed, to avoid an infinite postpone 379 * infinite postpone deadlock.
405 * deadlock.
406 */ 380 */
407 /* request postpone count limit */
408 int postpone_cnt; 381 int postpone_cnt;
409 382
410 /* 383 /*
@@ -419,18 +392,14 @@ typedef struct ide_tape_obj {
419 int tape_head; 392 int tape_head;
420 int last_tape_head; 393 int last_tape_head;
421 394
422 /* 395 /* Speed control at the tape buffers input/output */
423 * Speed control at the tape buffers input/output
424 */
425 unsigned long insert_time; 396 unsigned long insert_time;
426 int insert_size; 397 int insert_size;
427 int insert_speed; 398 int insert_speed;
428 int max_insert_speed; 399 int max_insert_speed;
429 int measure_insert_time; 400 int measure_insert_time;
430 401
431 /* 402 /* Speed regulation negative feedback loop */
432 * Speed regulation negative feedback loop
433 */
434 int speed_control; 403 int speed_control;
435 int pipeline_head_speed; 404 int pipeline_head_speed;
436 int controlled_pipeline_head_speed; 405 int controlled_pipeline_head_speed;
@@ -477,9 +446,7 @@ static void ide_tape_put(struct ide_tape_obj *tape)
477 mutex_unlock(&idetape_ref_mutex); 446 mutex_unlock(&idetape_ref_mutex);
478} 447}
479 448
480/* 449/* Tape door status */
481 * Tape door status
482 */
483#define DOOR_UNLOCKED 0 450#define DOOR_UNLOCKED 0
484#define DOOR_LOCKED 1 451#define DOOR_LOCKED 1
485#define DOOR_EXPLICITLY_LOCKED 2 452#define DOOR_EXPLICITLY_LOCKED 2
@@ -499,30 +466,23 @@ static void ide_tape_put(struct ide_tape_obj *tape)
499/* 0 = no tape is loaded, so we don't rewind after ejecting */ 466/* 0 = no tape is loaded, so we don't rewind after ejecting */
500#define IDETAPE_MEDIUM_PRESENT 9 467#define IDETAPE_MEDIUM_PRESENT 9
501 468
502/* 469/* A define for the READ BUFFER command */
503 * Some defines for the READ BUFFER command
504 */
505#define IDETAPE_RETRIEVE_FAULTY_BLOCK 6 470#define IDETAPE_RETRIEVE_FAULTY_BLOCK 6
506 471
507/* 472/* Some defines for the SPACE command */
508 * Some defines for the SPACE command
509 */
510#define IDETAPE_SPACE_OVER_FILEMARK 1 473#define IDETAPE_SPACE_OVER_FILEMARK 1
511#define IDETAPE_SPACE_TO_EOD 3 474#define IDETAPE_SPACE_TO_EOD 3
512 475
513/* 476/* Some defines for the LOAD UNLOAD command */
514 * Some defines for the LOAD UNLOAD command
515 */
516#define IDETAPE_LU_LOAD_MASK 1 477#define IDETAPE_LU_LOAD_MASK 1
517#define IDETAPE_LU_RETENSION_MASK 2 478#define IDETAPE_LU_RETENSION_MASK 2
518#define IDETAPE_LU_EOT_MASK 4 479#define IDETAPE_LU_EOT_MASK 4
519 480
520/* 481/*
521 * Special requests for our block device strategy routine. 482 * Special requests for our block device strategy routine.
522 * 483 *
523 * In order to service a character device command, we add special 484 * In order to service a character device command, we add special requests to
524 * requests to the tail of our block device request queue and wait 485 * the tail of our block device request queue and wait for their completion.
525 * for their completion.
526 */ 486 */
527 487
528enum { 488enum {
@@ -533,10 +493,7 @@ enum {
533 REQ_IDETAPE_READ_BUFFER = (1 << 4), 493 REQ_IDETAPE_READ_BUFFER = (1 << 4),
534}; 494};
535 495
536/* 496/* Error codes returned in rq->errors to the higher part of the driver. */
537 * Error codes which are returned in rq->errors to the higher part
538 * of the driver.
539 */
540#define IDETAPE_ERROR_GENERAL 101 497#define IDETAPE_ERROR_GENERAL 101
541#define IDETAPE_ERROR_FILEMARK 102 498#define IDETAPE_ERROR_FILEMARK 102
542#define IDETAPE_ERROR_EOD 103 499#define IDETAPE_ERROR_EOD 103
@@ -560,8 +517,8 @@ struct idetape_id_gcw {
560#define IDETAPE_CAPABILITIES_PAGE 0x2a 517#define IDETAPE_CAPABILITIES_PAGE 0x2a
561 518
562/* 519/*
563 * The variables below are used for the character device interface. 520 * The variables below are used for the character device interface. Additional
564 * Additional state variables are defined in our ide_drive_t structure. 521 * state variables are defined in our ide_drive_t structure.
565 */ 522 */
566static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES]; 523static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES];
567 524
@@ -579,10 +536,6 @@ static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
579 return tape; 536 return tape;
580} 537}
581 538
582/*
583 * Function declarations
584 *
585 */
586static int idetape_chrdev_release (struct inode *inode, struct file *filp); 539static int idetape_chrdev_release (struct inode *inode, struct file *filp);
587static void idetape_write_release (ide_drive_t *drive, unsigned int minor); 540static void idetape_write_release (ide_drive_t *drive, unsigned int minor);
588 541
@@ -711,9 +664,6 @@ static struct request *idetape_next_rq_storage (ide_drive_t *drive)
711 return (&tape->rq_stack[tape->rq_stack_index++]); 664 return (&tape->rq_stack[tape->rq_stack_index++]);
712} 665}
713 666
714/*
715 * idetape_init_pc initializes a packet command.
716 */
717static void idetape_init_pc (idetape_pc_t *pc) 667static void idetape_init_pc (idetape_pc_t *pc)
718{ 668{
719 memset(pc->c, 0, 12); 669 memset(pc->c, 0, 12);
@@ -809,10 +759,7 @@ static void idetape_activate_next_stage(ide_drive_t *drive)
809 tape->next_stage = stage->next; 759 tape->next_stage = stage->next;
810} 760}
811 761
812/* 762/* Free a stage along with its related buffers completely. */
813 * idetape_kfree_stage calls kfree to completely free a stage, along with
814 * its related buffers.
815 */
816static void __idetape_kfree_stage (idetape_stage_t *stage) 763static void __idetape_kfree_stage (idetape_stage_t *stage)
817{ 764{
818 struct idetape_bh *prev_bh, *bh = stage->bh; 765 struct idetape_bh *prev_bh, *bh = stage->bh;
@@ -840,8 +787,8 @@ static void idetape_kfree_stage (idetape_tape_t *tape, idetape_stage_t *stage)
840} 787}
841 788
842/* 789/*
843 * idetape_remove_stage_head removes tape->first_stage from the pipeline. 790 * Remove tape->first_stage from the pipeline. The caller should avoid race
844 * The caller should avoid race conditions. 791 * conditions.
845 */ 792 */
846static void idetape_remove_stage_head (ide_drive_t *drive) 793static void idetape_remove_stage_head (ide_drive_t *drive)
847{ 794{
@@ -899,8 +846,8 @@ static void idetape_abort_pipeline(ide_drive_t *drive,
899} 846}
900 847
901/* 848/*
902 * idetape_end_request is used to finish servicing a request, and to 849 * Finish servicing a request and insert a pending pipeline request into the
903 * insert a pending pipeline request into the main device queue. 850 * main device queue.
904 */ 851 */
905static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects) 852static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
906{ 853{
@@ -951,9 +898,7 @@ static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
951 if (tape->next_stage != NULL) { 898 if (tape->next_stage != NULL) {
952 idetape_activate_next_stage(drive); 899 idetape_activate_next_stage(drive);
953 900
954 /* 901 /* Insert the next request into the request queue. */
955 * Insert the next request into the request queue.
956 */
957 (void)ide_do_drive_cmd(drive, tape->active_data_rq, 902 (void)ide_do_drive_cmd(drive, tape->active_data_rq,
958 ide_end); 903 ide_end);
959 } else if (!error) { 904 } else if (!error) {
@@ -1020,23 +965,19 @@ static void idetape_init_rq(struct request *rq, u8 cmd)
1020} 965}
1021 966
1022/* 967/*
1023 * idetape_queue_pc_head generates a new packet command request in front 968 * Generate a new packet command request in front of the request queue, before
1024 * of the request queue, before the current request, so that it will be 969 * the current request, so that it will be processed immediately, on the next
1025 * processed immediately, on the next pass through the driver. 970 * pass through the driver. The function below is called from the request
1026 * 971 * handling part of the driver (the "bottom" part). Safe storage for the request
1027 * idetape_queue_pc_head is called from the request handling part of 972 * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
1028 * the driver (the "bottom" part). Safe storage for the request should
1029 * be allocated with idetape_next_pc_storage and idetape_next_rq_storage
1030 * before calling idetape_queue_pc_head.
1031 * 973 *
1032 * Memory for those requests is pre-allocated at initialization time, and 974 * Memory for those requests is pre-allocated at initialization time, and is
1033 * is limited to IDETAPE_PC_STACK requests. We assume that we have enough 975 * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
1034 * space for the maximum possible number of inter-dependent packet commands. 976 * the maximum possible number of inter-dependent packet commands.
1035 * 977 *
1036 * The higher level of the driver - The ioctl handler and the character 978 * The higher level of the driver - The ioctl handler and the character device
1037 * device handling functions should queue request to the lower level part 979 * handling functions should queue request to the lower level part and wait for
1038 * and wait for their completion using idetape_queue_pc_tail or 980 * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
1039 * idetape_queue_rw_tail.
1040 */ 981 */
1041static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq) 982static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
1042{ 983{
@@ -1069,9 +1010,8 @@ static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
1069} 1010}
1070 1011
1071/* 1012/*
1072 * idetape_postpone_request postpones the current request so that 1013 * Postpone the current request so that ide.c will be able to service requests
1073 * ide.c will be able to service requests from another device on 1014 * from another device on the same hwgroup while we are polling for DSC.
1074 * the same hwgroup while we are polling for DSC.
1075 */ 1015 */
1076static void idetape_postpone_request (ide_drive_t *drive) 1016static void idetape_postpone_request (ide_drive_t *drive)
1077{ 1017{
@@ -1258,46 +1198,40 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
1258} 1198}
1259 1199
1260/* 1200/*
1261 * Packet Command Interface 1201 * Packet Command Interface
1262 * 1202 *
1263 * The current Packet Command is available in tape->pc, and will not 1203 * The current Packet Command is available in tape->pc, and will not change
1264 * change until we finish handling it. Each packet command is associated 1204 * until we finish handling it. Each packet command is associated with a
1265 * with a callback function that will be called when the command is 1205 * callback function that will be called when the command is finished.
1266 * finished.
1267 * 1206 *
1268 * The handling will be done in three stages: 1207 * The handling will be done in three stages:
1269 * 1208 *
1270 * 1. idetape_issue_pc will send the packet command to the 1209 * 1. idetape_issue_pc will send the packet command to the drive, and will set
1271 * drive, and will set the interrupt handler to idetape_pc_intr. 1210 * the interrupt handler to idetape_pc_intr.
1272 * 1211 *
1273 * 2. On each interrupt, idetape_pc_intr will be called. This step 1212 * 2. On each interrupt, idetape_pc_intr will be called. This step will be
1274 * will be repeated until the device signals us that no more 1213 * repeated until the device signals us that no more interrupts will be issued.
1275 * interrupts will be issued.
1276 * 1214 *
1277 * 3. ATAPI Tape media access commands have immediate status with a 1215 * 3. ATAPI Tape media access commands have immediate status with a delayed
1278 * delayed process. In case of a successful initiation of a 1216 * process. In case of a successful initiation of a media access packet command,
1279 * media access packet command, the DSC bit will be set when the 1217 * the DSC bit will be set when the actual execution of the command is finished.
1280 * actual execution of the command is finished. 1218 * Since the tape drive will not issue an interrupt, we have to poll for this
1281 * Since the tape drive will not issue an interrupt, we have to 1219 * event. In this case, we define the request as "low priority request" by
1282 * poll for this event. In this case, we define the request as 1220 * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
1283 * "low priority request" by setting rq_status to 1221 * exit the driver.
1284 * IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and exit
1285 * the driver.
1286 * 1222 *
1287 * ide.c will then give higher priority to requests which 1223 * ide.c will then give higher priority to requests which originate from the
1288 * originate from the other device, until will change rq_status 1224 * other device, until will change rq_status to RQ_ACTIVE.
1289 * to RQ_ACTIVE.
1290 * 1225 *
1291 * 4. When the packet command is finished, it will be checked for errors. 1226 * 4. When the packet command is finished, it will be checked for errors.
1292 * 1227 *
1293 * 5. In case an error was found, we queue a request sense packet 1228 * 5. In case an error was found, we queue a request sense packet command in
1294 * command in front of the request queue and retry the operation 1229 * front of the request queue and retry the operation up to
1295 * up to IDETAPE_MAX_PC_RETRIES times. 1230 * IDETAPE_MAX_PC_RETRIES times.
1296 *
1297 * 6. In case no error was found, or we decided to give up and not
1298 * to retry again, the callback function will be called and then
1299 * we will handle the next request.
1300 * 1231 *
1232 * 6. In case no error was found, or we decided to give up and not to retry
1233 * again, the callback function will be called and then we will handle the next
1234 * request.
1301 */ 1235 */
1302static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive) 1236static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
1303{ 1237{
@@ -1363,9 +1297,9 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive, idetape_pc_t *pc)
1363 if (pc->retries > IDETAPE_MAX_PC_RETRIES || 1297 if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
1364 test_bit(PC_ABORT, &pc->flags)) { 1298 test_bit(PC_ABORT, &pc->flags)) {
1365 /* 1299 /*
1366 * We will "abort" retrying a packet command in case 1300 * We will "abort" retrying a packet command in case legitimate
1367 * a legitimate error code was received (crossing a 1301 * error code was received (crossing a filemark, or end of the
1368 * filemark, or end of the media, for example). 1302 * media, for example).
1369 */ 1303 */
1370 if (!test_bit(PC_ABORT, &pc->flags)) { 1304 if (!test_bit(PC_ABORT, &pc->flags)) {
1371 if (!(pc->c[0] == TEST_UNIT_READY && 1305 if (!(pc->c[0] == TEST_UNIT_READY &&
@@ -1416,9 +1350,6 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive, idetape_pc_t *pc)
1416 } 1350 }
1417} 1351}
1418 1352
1419/*
1420 * General packet command callback function.
1421 */
1422static ide_startstop_t idetape_pc_callback (ide_drive_t *drive) 1353static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
1423{ 1354{
1424 idetape_tape_t *tape = drive->driver_data; 1355 idetape_tape_t *tape = drive->driver_data;
@@ -1429,15 +1360,14 @@ static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
1429 return ide_stopped; 1360 return ide_stopped;
1430} 1361}
1431 1362
1432/* 1363/* A mode sense command is used to "sense" tape parameters. */
1433 * A mode sense command is used to "sense" tape parameters.
1434 */
1435static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code) 1364static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
1436{ 1365{
1437 idetape_init_pc(pc); 1366 idetape_init_pc(pc);
1438 pc->c[0] = MODE_SENSE; 1367 pc->c[0] = MODE_SENSE;
1439 if (page_code != IDETAPE_BLOCK_DESCRIPTOR) 1368 if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
1440 pc->c[1] = 8; /* DBD = 1 - Don't return block descriptors */ 1369 /* DBD = 1 - Don't return block descriptors */
1370 pc->c[1] = 8;
1441 pc->c[2] = page_code; 1371 pc->c[2] = page_code;
1442 /* 1372 /*
1443 * Changed pc->c[3] to 0 (255 will at best return unused info). 1373 * Changed pc->c[3] to 0 (255 will at best return unused info).
@@ -1447,7 +1377,8 @@ static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
1447 * and return an error when 255 is used. 1377 * and return an error when 255 is used.
1448 */ 1378 */
1449 pc->c[3] = 0; 1379 pc->c[3] = 0;
1450 pc->c[4] = 255; /* (We will just discard data in that case) */ 1380 /* We will just discard data in that case */
1381 pc->c[4] = 255;
1451 if (page_code == IDETAPE_BLOCK_DESCRIPTOR) 1382 if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
1452 pc->request_transfer = 12; 1383 pc->request_transfer = 12;
1453 else if (page_code == IDETAPE_CAPABILITIES_PAGE) 1384 else if (page_code == IDETAPE_CAPABILITIES_PAGE)
@@ -1619,9 +1550,6 @@ static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc, uns
1619 set_bit(PC_DMA_RECOMMENDED, &pc->flags); 1550 set_bit(PC_DMA_RECOMMENDED, &pc->flags);
1620} 1551}
1621 1552
1622/*
1623 * idetape_do_request is our request handling function.
1624 */
1625static ide_startstop_t idetape_do_request(ide_drive_t *drive, 1553static ide_startstop_t idetape_do_request(ide_drive_t *drive,
1626 struct request *rq, sector_t block) 1554 struct request *rq, sector_t block)
1627{ 1555{
@@ -1635,18 +1563,14 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
1635 rq->sector, rq->nr_sectors, rq->current_nr_sectors); 1563 rq->sector, rq->nr_sectors, rq->current_nr_sectors);
1636 1564
1637 if (!blk_special_request(rq)) { 1565 if (!blk_special_request(rq)) {
1638 /* 1566 /* We do not support buffer cache originated requests. */
1639 * We do not support buffer cache originated requests.
1640 */
1641 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in " 1567 printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
1642 "request queue (%d)\n", drive->name, rq->cmd_type); 1568 "request queue (%d)\n", drive->name, rq->cmd_type);
1643 ide_end_request(drive, 0, 0); 1569 ide_end_request(drive, 0, 0);
1644 return ide_stopped; 1570 return ide_stopped;
1645 } 1571 }
1646 1572
1647 /* 1573 /* Retry a failed packet command */
1648 * Retry a failed packet command
1649 */
1650 if (tape->failed_pc != NULL && 1574 if (tape->failed_pc != NULL &&
1651 tape->pc->c[0] == REQUEST_SENSE) { 1575 tape->pc->c[0] == REQUEST_SENSE) {
1652 return idetape_issue_pc(drive, tape->failed_pc); 1576 return idetape_issue_pc(drive, tape->failed_pc);
@@ -1733,9 +1657,7 @@ out:
1733 return idetape_issue_pc(drive, pc); 1657 return idetape_issue_pc(drive, pc);
1734} 1658}
1735 1659
1736/* 1660/* Pipeline related functions */
1737 * Pipeline related functions
1738 */
1739static inline int idetape_pipeline_active (idetape_tape_t *tape) 1661static inline int idetape_pipeline_active (idetape_tape_t *tape)
1740{ 1662{
1741 int rc1, rc2; 1663 int rc1, rc2;
@@ -1746,16 +1668,16 @@ static inline int idetape_pipeline_active (idetape_tape_t *tape)
1746} 1668}
1747 1669
1748/* 1670/*
1749 * idetape_kmalloc_stage uses __get_free_page to allocate a pipeline 1671 * The function below uses __get_free_page to allocate a pipeline stage, along
1750 * stage, along with all the necessary small buffers which together make 1672 * with all the necessary small buffers which together make a buffer of size
1751 * a buffer of size tape->stage_size (or a bit more). We attempt to 1673 * tape->stage_size (or a bit more). We attempt to combine sequential pages as
1752 * combine sequential pages as much as possible. 1674 * much as possible.
1753 * 1675 *
1754 * Returns a pointer to the new allocated stage, or NULL if we 1676 * It returns a pointer to the new allocated stage, or NULL if we can't (or
1755 * can't (or don't want to) allocate a stage. 1677 * don't want to) allocate a stage.
1756 * 1678 *
1757 * Pipeline stages are optional and are used to increase performance. 1679 * Pipeline stages are optional and are used to increase performance. If we
1758 * If we can't allocate them, we'll manage without them. 1680 * can't allocate them, we'll manage without them.
1759 */ 1681 */
1760static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear) 1682static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear)
1761{ 1683{
@@ -1913,9 +1835,7 @@ static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage
1913 idetape_init_merge_stage(tape); 1835 idetape_init_merge_stage(tape);
1914} 1836}
1915 1837
1916/* 1838/* Add a new stage at the end of the pipeline. */
1917 * idetape_add_stage_tail adds a new stage at the end of the pipeline.
1918 */
1919static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage) 1839static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
1920{ 1840{
1921 idetape_tape_t *tape = drive->driver_data; 1841 idetape_tape_t *tape = drive->driver_data;
@@ -1937,12 +1857,9 @@ static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
1937 spin_unlock_irqrestore(&tape->lock, flags); 1857 spin_unlock_irqrestore(&tape->lock, flags);
1938} 1858}
1939 1859
1940/* 1860/* Install a completion in a pending request and sleep until it is serviced. The
1941 * idetape_wait_for_request installs a completion in a pending request 1861 * caller should ensure that the request will not be serviced before we install
1942 * and sleeps until it is serviced. 1862 * the completion (usually by disabling interrupts).
1943 *
1944 * The caller should ensure that the request will not be serviced
1945 * before we install the completion (usually by disabling interrupts).
1946 */ 1863 */
1947static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq) 1864static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
1948{ 1865{
@@ -1996,12 +1913,8 @@ static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
1996} 1913}
1997 1914
1998/* 1915/*
1999 * idetape_create_write_filemark_cmd will: 1916 * Write a filemark if write_filemark=1. Flush the device buffers without
2000 * 1917 * writing a filemark otherwise.
2001 * 1. Write a filemark if write_filemark=1.
2002 * 2. Flush the device buffers without writing a filemark
2003 * if write_filemark=0.
2004 *
2005 */ 1918 */
2006static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark) 1919static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark)
2007{ 1920{
@@ -2020,24 +1933,17 @@ static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc)
2020} 1933}
2021 1934
2022/* 1935/*
2023 * idetape_queue_pc_tail is based on the following functions: 1936 * We add a special packet command request to the tail of the request queue, and
2024 * 1937 * wait for it to be serviced. This is not to be called from within the request
2025 * ide_do_drive_cmd from ide.c 1938 * handling part of the driver! We allocate here data on the stack and it is
2026 * cdrom_queue_request and cdrom_queue_packet_command from ide-cd.c 1939 * valid until the request is finished. This is not the case for the bottom part
2027 * 1940 * of the driver, where we are always leaving the functions to wait for an
2028 * We add a special packet command request to the tail of the request 1941 * interrupt or a timer event.
2029 * queue, and wait for it to be serviced.
2030 * 1942 *
2031 * This is not to be called from within the request handling part 1943 * From the bottom part of the driver, we should allocate safe memory using
2032 * of the driver ! We allocate here data in the stack, and it is valid 1944 * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
2033 * until the request is finished. This is not the case for the bottom 1945 * to the request list without waiting for it to be serviced! In that case, we
2034 * part of the driver, where we are always leaving the functions to wait 1946 * usually use idetape_queue_pc_head().
2035 * for an interrupt or a timer event.
2036 *
2037 * From the bottom part of the driver, we should allocate safe memory
2038 * using idetape_next_pc_storage and idetape_next_rq_storage, and add
2039 * the request to the request list without waiting for it to be serviced !
2040 * In that case, we usually use idetape_queue_pc_head.
2041 */ 1947 */
2042static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc) 1948static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
2043{ 1949{
@@ -2065,9 +1971,7 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
2065 idetape_pc_t pc; 1971 idetape_pc_t pc;
2066 int load_attempted = 0; 1972 int load_attempted = 0;
2067 1973
2068 /* 1974 /* Wait for the tape to become ready */
2069 * Wait for the tape to become ready
2070 */
2071 set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags); 1975 set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
2072 timeout += jiffies; 1976 timeout += jiffies;
2073 while (time_before(jiffies, timeout)) { 1977 while (time_before(jiffies, timeout)) {
@@ -2075,7 +1979,8 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
2075 if (!__idetape_queue_pc_tail(drive, &pc)) 1979 if (!__idetape_queue_pc_tail(drive, &pc))
2076 return 0; 1980 return 0;
2077 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2) 1981 if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
2078 || (tape->asc == 0x3A)) { /* no media */ 1982 || (tape->asc == 0x3A)) {
1983 /* no media */
2079 if (load_attempted) 1984 if (load_attempted)
2080 return -ENOMEDIUM; 1985 return -ENOMEDIUM;
2081 idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK); 1986 idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK);
@@ -2203,13 +2108,10 @@ static int __idetape_discard_read_pipeline (ide_drive_t *drive)
2203} 2108}
2204 2109
2205/* 2110/*
2206 * idetape_position_tape positions the tape to the requested block 2111 * Position the tape to the requested block using the LOCATE packet command.
2207 * using the LOCATE packet command. A READ POSITION command is then 2112 * A READ POSITION command is then issued to check where we are positioned. Like
2208 * issued to check where we are positioned. 2113 * all higher level operations, we queue the commands at the tail of the request
2209 * 2114 * queue and wait for their completion.
2210 * Like all higher level operations, we queue the commands at the tail
2211 * of the request queue and wait for their completion.
2212 *
2213 */ 2115 */
2214static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip) 2116static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip)
2215{ 2117{
@@ -2247,8 +2149,8 @@ static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_posit
2247} 2149}
2248 2150
2249/* 2151/*
2250 * idetape_queue_rw_tail generates a read/write request for the block 2152 * Generate a read/write request for the block device interface and wait for it
2251 * device interface and wait for it to be serviced. 2153 * to be serviced.
2252 */ 2154 */
2253static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh) 2155static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh)
2254{ 2156{
@@ -2343,15 +2245,15 @@ static void idetape_wait_first_stage (ide_drive_t *drive)
2343} 2245}
2344 2246
2345/* 2247/*
2346 * idetape_add_chrdev_write_request tries to add a character device 2248 * Try to add a character device originated write request to our pipeline. In
2347 * originated write request to our pipeline. In case we don't succeed, 2249 * case we don't succeed, we revert to non-pipelined operation mode for this
2348 * we revert to non-pipelined operation mode for this request. 2250 * request. In order to accomplish that, we
2349 * 2251 *
2350 * 1. Try to allocate a new pipeline stage. 2252 * 1. Try to allocate a new pipeline stage.
2351 * 2. If we can't, wait for more and more requests to be serviced 2253 * 2. If we can't, wait for more and more requests to be serviced and try again
2352 * and try again each time. 2254 * each time.
2353 * 3. If we still can't allocate a stage, fallback to 2255 * 3. If we still can't allocate a stage, fallback to non-pipelined operation
2354 * non-pipelined operation mode for this request. 2256 * mode for this request.
2355 */ 2257 */
2356static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks) 2258static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
2357{ 2259{
@@ -2362,10 +2264,7 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
2362 2264
2363 debug_log(DBG_CHRDEV, "Enter %s\n", __func__); 2265 debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
2364 2266
2365 /* 2267 /* Attempt to allocate a new stage. Beware possible race conditions. */
2366 * Attempt to allocate a new stage.
2367 * Pay special attention to possible race conditions.
2368 */
2369 while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) { 2268 while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
2370 spin_lock_irqsave(&tape->lock, flags); 2269 spin_lock_irqsave(&tape->lock, flags);
2371 if (idetape_pipeline_active(tape)) { 2270 if (idetape_pipeline_active(tape)) {
@@ -2377,8 +2276,8 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
2377 if (idetape_pipeline_active(tape)) 2276 if (idetape_pipeline_active(tape))
2378 continue; 2277 continue;
2379 /* 2278 /*
2380 * Linux is short on memory. Fallback to 2279 * The machine is short on memory. Fallback to non-
2381 * non-pipelined operation mode for this request. 2280 * pipelined operation mode for this request.
2382 */ 2281 */
2383 return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh); 2282 return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
2384 } 2283 }
@@ -2395,11 +2294,11 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
2395 idetape_calculate_speeds(drive); 2294 idetape_calculate_speeds(drive);
2396 2295
2397 /* 2296 /*
2398 * Estimate whether the tape has stopped writing by checking 2297 * Estimate whether the tape has stopped writing by checking if our
2399 * if our write pipeline is currently empty. If we are not 2298 * write pipeline is currently empty. If we are not writing anymore,
2400 * writing anymore, wait for the pipeline to be full enough 2299 * wait for the pipeline to be almost completely full (90%) before
2401 * (90%) before starting to service requests, so that we will 2300 * starting to service requests, so that we will be able to keep up with
2402 * be able to keep up with the higher speeds of the tape. 2301 * the higher speeds of the tape.
2403 */ 2302 */
2404 if (!idetape_pipeline_active(tape)) { 2303 if (!idetape_pipeline_active(tape)) {
2405 if (tape->nr_stages >= tape->max_stages * 9 / 10 || 2304 if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
@@ -2420,8 +2319,8 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
2420} 2319}
2421 2320
2422/* 2321/*
2423 * idetape_wait_for_pipeline will wait until all pending pipeline 2322 * Wait until all pending pipeline requests are serviced. Typically called on
2424 * requests are serviced. Typically called on device close. 2323 * device close.
2425 */ 2324 */
2426static void idetape_wait_for_pipeline (ide_drive_t *drive) 2325static void idetape_wait_for_pipeline (ide_drive_t *drive)
2427{ 2326{
@@ -2490,10 +2389,10 @@ static void idetape_empty_write_pipeline (ide_drive_t *drive)
2490 tape->chrdev_dir = IDETAPE_DIR_NONE; 2389 tape->chrdev_dir = IDETAPE_DIR_NONE;
2491 2390
2492 /* 2391 /*
2493 * On the next backup, perform the feedback loop again. 2392 * On the next backup, perform the feedback loop again. (I don't want to
2494 * (I don't want to keep sense information between backups, 2393 * keep sense information between backups, as some systems are
2495 * as some systems are constantly on, and the system load 2394 * constantly on, and the system load can be totally different on the
2496 * can be totally different on the next backup). 2395 * next backup).
2497 */ 2396 */
2498 tape->max_stages = tape->min_pipeline; 2397 tape->max_stages = tape->min_pipeline;
2499 if (tape->first_stage != NULL || 2398 if (tape->first_stage != NULL ||
@@ -2545,11 +2444,10 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages)
2545 tape->chrdev_dir = IDETAPE_DIR_READ; 2444 tape->chrdev_dir = IDETAPE_DIR_READ;
2546 2445
2547 /* 2446 /*
2548 * Issue a read 0 command to ensure that DSC handshake 2447 * Issue a read 0 command to ensure that DSC handshake is
2549 * is switched from completion mode to buffer available 2448 * switched from completion mode to buffer available mode.
2550 * mode. 2449 * No point in issuing this if DSC overlap isn't supported, some
2551 * No point in issuing this if DSC overlap isn't supported, 2450 * drives (Seagate STT3401A) will return an error.
2552 * some drives (Seagate STT3401A) will return an error.
2553 */ 2451 */
2554 if (drive->dsc_overlap) { 2452 if (drive->dsc_overlap) {
2555 bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh); 2453 bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh);
@@ -2590,9 +2488,8 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages)
2590} 2488}
2591 2489
2592/* 2490/*
2593 * idetape_add_chrdev_read_request is called from idetape_chrdev_read 2491 * Called from idetape_chrdev_read() to service a character device read request
2594 * to service a character device read request and add read-ahead 2492 * and add read-ahead requests to our pipeline.
2595 * requests to our pipeline.
2596 */ 2493 */
2597static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks) 2494static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
2598{ 2495{
@@ -2603,16 +2500,11 @@ static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
2603 2500
2604 debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks); 2501 debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
2605 2502
2606 /* 2503 /* If we are at a filemark, return a read length of 0 */
2607 * If we are at a filemark, return a read length of 0
2608 */
2609 if (test_bit(IDETAPE_FILEMARK, &tape->flags)) 2504 if (test_bit(IDETAPE_FILEMARK, &tape->flags))
2610 return 0; 2505 return 0;
2611 2506
2612 /* 2507 /* Wait for the next block to reach the head of the pipeline. */
2613 * Wait for the next block to be available at the head
2614 * of the pipeline
2615 */
2616 idetape_init_read(drive, tape->max_stages); 2508 idetape_init_read(drive, tape->max_stages);
2617 if (tape->first_stage == NULL) { 2509 if (tape->first_stage == NULL) {
2618 if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags)) 2510 if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
@@ -2651,7 +2543,7 @@ static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
2651 idetape_tape_t *tape = drive->driver_data; 2543 idetape_tape_t *tape = drive->driver_data;
2652 struct idetape_bh *bh; 2544 struct idetape_bh *bh;
2653 int blocks; 2545 int blocks;
2654 2546
2655 while (bcount) { 2547 while (bcount) {
2656 unsigned int count; 2548 unsigned int count;
2657 2549
@@ -2691,10 +2583,9 @@ static int idetape_pipeline_size (ide_drive_t *drive)
2691} 2583}
2692 2584
2693/* 2585/*
2694 * Rewinds the tape to the Beginning Of the current Partition (BOP). 2586 * Rewinds the tape to the Beginning Of the current Partition (BOP). We
2695 * 2587 * currently support only one partition.
2696 * We currently support only one partition. 2588 */
2697 */
2698static int idetape_rewind_tape (ide_drive_t *drive) 2589static int idetape_rewind_tape (ide_drive_t *drive)
2699{ 2590{
2700 int retval; 2591 int retval;
@@ -2716,13 +2607,7 @@ static int idetape_rewind_tape (ide_drive_t *drive)
2716 return 0; 2607 return 0;
2717} 2608}
2718 2609
2719/* 2610/* mtio.h compatible commands should be issued to the chrdev interface. */
2720 * Our special ide-tape ioctl's.
2721 *
2722 * Currently there aren't any ioctl's.
2723 * mtio.h compatible commands should be issued to the character device
2724 * interface.
2725 */
2726static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg) 2611static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg)
2727{ 2612{
2728 idetape_tape_t *tape = drive->driver_data; 2613 idetape_tape_t *tape = drive->driver_data;
@@ -2756,13 +2641,11 @@ static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned l
2756} 2641}
2757 2642
2758/* 2643/*
2759 * idetape_space_over_filemarks is now a bit more complicated than just 2644 * The function below is now a bit more complicated than just passing the
2760 * passing the command to the tape since we may have crossed some 2645 * command to the tape since we may have crossed some filemarks during our
2761 * filemarks during our pipelined read-ahead mode. 2646 * pipelined read-ahead mode. As a minor side effect, the pipeline enables us to
2762 * 2647 * support MTFSFM when the filemark is in our internal pipeline even if the tape
2763 * As a minor side effect, the pipeline enables us to support MTFSFM when 2648 * doesn't support spacing over filemarks in the reverse direction.
2764 * the filemark is in our internal pipeline even if the tape doesn't
2765 * support spacing over filemarks in the reverse direction.
2766 */ 2649 */
2767static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count) 2650static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count)
2768{ 2651{
@@ -2781,10 +2664,7 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
2781 } 2664 }
2782 2665
2783 if (tape->chrdev_dir == IDETAPE_DIR_READ) { 2666 if (tape->chrdev_dir == IDETAPE_DIR_READ) {
2784 /* 2667 /* its a read-ahead buffer, scan it for crossed filemarks. */
2785 * We have a read-ahead buffer. Scan it for crossed
2786 * filemarks.
2787 */
2788 tape->merge_stage_size = 0; 2668 tape->merge_stage_size = 0;
2789 if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags)) 2669 if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
2790 ++count; 2670 ++count;
@@ -2797,13 +2677,15 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
2797 spin_lock_irqsave(&tape->lock, flags); 2677 spin_lock_irqsave(&tape->lock, flags);
2798 if (tape->first_stage == tape->active_stage) { 2678 if (tape->first_stage == tape->active_stage) {
2799 /* 2679 /*
2800 * We have reached the active stage in the read pipeline. 2680 * We have reached the active stage in the read
2801 * There is no point in allowing the drive to continue 2681 * pipeline. There is no point in allowing the
2802 * reading any farther, so we stop the pipeline. 2682 * drive to continue reading any farther, so we
2683 * stop the pipeline.
2803 * 2684 *
2804 * This section should be moved to a separate subroutine, 2685 * This section should be moved to a separate
2805 * because a similar function is performed in 2686 * subroutine because similar operations are
2806 * __idetape_discard_read_pipeline(), for example. 2687 * done in __idetape_discard_read_pipeline(),
2688 * for example.
2807 */ 2689 */
2808 tape->next_stage = NULL; 2690 tape->next_stage = NULL;
2809 spin_unlock_irqrestore(&tape->lock, flags); 2691 spin_unlock_irqrestore(&tape->lock, flags);
@@ -2819,8 +2701,8 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
2819 } 2701 }
2820 2702
2821 /* 2703 /*
2822 * The filemark was not found in our internal pipeline. 2704 * The filemark was not found in our internal pipeline; now we can issue
2823 * Now we can issue the space command. 2705 * the space command.
2824 */ 2706 */
2825 switch (mt_op) { 2707 switch (mt_op) {
2826 case MTFSF: 2708 case MTFSF:
@@ -2843,21 +2725,19 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
2843 2725
2844 2726
2845/* 2727/*
2846 * Our character device read / write functions. 2728 * Our character device read / write functions.
2847 * 2729 *
2848 * The tape is optimized to maximize throughput when it is transferring 2730 * The tape is optimized to maximize throughput when it is transferring an
2849 * an integral number of the "continuous transfer limit", which is 2731 * integral number of the "continuous transfer limit", which is a parameter of
2850 * a parameter of the specific tape (26 KB on my particular tape). 2732 * the specific tape (26kB on my particular tape, 32kB for Onstream).
2851 * (32 kB for Onstream)
2852 * 2733 *
2853 * As of version 1.3 of the driver, the character device provides an 2734 * As of version 1.3 of the driver, the character device provides an abstract
2854 * abstract continuous view of the media - any mix of block sizes (even 1 2735 * continuous view of the media - any mix of block sizes (even 1 byte) on the
2855 * byte) on the same backup/restore procedure is supported. The driver 2736 * same backup/restore procedure is supported. The driver will internally
2856 * will internally convert the requests to the recommended transfer unit, 2737 * convert the requests to the recommended transfer unit, so that an unmatch
2857 * so that an unmatch between the user's block size to the recommended 2738 * between the user's block size to the recommended size will only result in a
2858 * size will only result in a (slightly) increased driver overhead, but 2739 * (slightly) increased driver overhead, but will no longer hit performance.
2859 * will no longer hit performance. 2740 * This is not applicable to Onstream.
2860 * This is not applicable to Onstream.
2861 */ 2741 */
2862static ssize_t idetape_chrdev_read (struct file *file, char __user *buf, 2742static ssize_t idetape_chrdev_read (struct file *file, char __user *buf,
2863 size_t count, loff_t *ppos) 2743 size_t count, loff_t *ppos)
@@ -2950,11 +2830,10 @@ static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
2950 idetape_init_merge_stage(tape); 2830 idetape_init_merge_stage(tape);
2951 2831
2952 /* 2832 /*
2953 * Issue a write 0 command to ensure that DSC handshake 2833 * Issue a write 0 command to ensure that DSC handshake is
2954 * is switched from completion mode to buffer available 2834 * switched from completion mode to buffer available mode. No
2955 * mode. 2835 * point in issuing this if DSC overlap isn't supported, some
2956 * No point in issuing this if DSC overlap isn't supported, 2836 * drives (Seagate STT3401A) will return an error.
2957 * some drives (Seagate STT3401A) will return an error.
2958 */ 2837 */
2959 if (drive->dsc_overlap) { 2838 if (drive->dsc_overlap) {
2960 ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh); 2839 ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh);
@@ -3045,9 +2924,7 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
3045 2924
3046 debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n", 2925 debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
3047 mt_op, mt_count); 2926 mt_op, mt_count);
3048 /* 2927 /* Commands which need our pipelined read-ahead stages. */
3049 * Commands which need our pipelined read-ahead stages.
3050 */
3051 switch (mt_op) { 2928 switch (mt_op) {
3052 case MTFSF: 2929 case MTFSF:
3053 case MTFSFM: 2930 case MTFSFM:
@@ -3235,9 +3112,6 @@ static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
3235 tape->drv_write_prot = (pc.buffer[2] & 0x80) >> 7; 3112 tape->drv_write_prot = (pc.buffer[2] & 0x80) >> 7;
3236} 3113}
3237 3114
3238/*
3239 * Our character device open function.
3240 */
3241static int idetape_chrdev_open (struct inode *inode, struct file *filp) 3115static int idetape_chrdev_open (struct inode *inode, struct file *filp)
3242{ 3116{
3243 unsigned int minor = iminor(inode), i = minor & ~0xc0; 3117 unsigned int minor = iminor(inode), i = minor & ~0xc0;
@@ -3304,9 +3178,7 @@ static int idetape_chrdev_open (struct inode *inode, struct file *filp)
3304 } 3178 }
3305 } 3179 }
3306 3180
3307 /* 3181 /* Lock the tape drive door so user can't eject. */
3308 * Lock the tape drive door so user can't eject.
3309 */
3310 if (tape->chrdev_dir == IDETAPE_DIR_NONE) { 3182 if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
3311 if (idetape_create_prevent_cmd(drive, &pc, 1)) { 3183 if (idetape_create_prevent_cmd(drive, &pc, 1)) {
3312 if (!idetape_queue_pc_tail(drive, &pc)) { 3184 if (!idetape_queue_pc_tail(drive, &pc)) {
@@ -3341,9 +3213,6 @@ static void idetape_write_release (ide_drive_t *drive, unsigned int minor)
3341 idetape_flush_tape_buffers(drive); 3213 idetape_flush_tape_buffers(drive);
3342} 3214}
3343 3215
3344/*
3345 * Our character device release function.
3346 */
3347static int idetape_chrdev_release (struct inode *inode, struct file *filp) 3216static int idetape_chrdev_release (struct inode *inode, struct file *filp)
3348{ 3217{
3349 struct ide_tape_obj *tape = ide_tape_f(filp); 3218 struct ide_tape_obj *tape = ide_tape_f(filp);
@@ -3500,9 +3369,6 @@ static void idetape_add_settings (ide_drive_t *drive)
3500{ 3369{
3501 idetape_tape_t *tape = drive->driver_data; 3370 idetape_tape_t *tape = drive->driver_data;
3502 3371
3503/*
3504 * drive setting name read/write data type min max mul_factor div_factor data pointer set function
3505 */
3506 ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff, 3372 ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
3507 1, 2, (u16 *)&tape->caps[16], NULL); 3373 1, 2, (u16 *)&tape->caps[16], NULL);
3508 ide_add_setting(drive, "pipeline_min", SETTING_RW, TYPE_INT, 1, 0xffff, tape->stage_size / 1024, 1, &tape->min_pipeline, NULL); 3374 ide_add_setting(drive, "pipeline_min", SETTING_RW, TYPE_INT, 1, 0xffff, tape->stage_size / 1024, 1, &tape->min_pipeline, NULL);
@@ -3529,16 +3395,15 @@ static inline void idetape_add_settings(ide_drive_t *drive) { ; }
3529#endif 3395#endif
3530 3396
3531/* 3397/*
3532 * ide_setup is called to: 3398 * The function below is called to:
3533 * 3399 *
3534 * 1. Initialize our various state variables. 3400 * 1. Initialize our various state variables.
3535 * 2. Ask the tape for its capabilities. 3401 * 2. Ask the tape for its capabilities.
3536 * 3. Allocate a buffer which will be used for data 3402 * 3. Allocate a buffer which will be used for data transfer. The buffer size
3537 * transfer. The buffer size is chosen based on 3403 * is chosen based on the recommendation which we received in step 2.
3538 * the recommendation which we received in step (2).
3539 * 3404 *
3540 * Note that at this point ide.c already assigned us an irq, so that 3405 * Note that at this point ide.c already assigned us an irq, so that we can
3541 * we can queue requests here and wait for their completion. 3406 * queue requests here and wait for their completion.
3542 */ 3407 */
3543static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor) 3408static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
3544{ 3409{
@@ -3572,7 +3437,7 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
3572 set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags); 3437 set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);
3573 3438
3574 tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10; 3439 tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10;
3575 3440
3576 idetape_get_inquiry_results(drive); 3441 idetape_get_inquiry_results(drive);
3577 idetape_get_mode_sense_results(drive); 3442 idetape_get_mode_sense_results(drive);
3578 ide_tape_get_bsize_from_bdesc(drive); 3443 ide_tape_get_bsize_from_bdesc(drive);
@@ -3595,9 +3460,7 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
3595 3460
3596 tape->max_stages = speed * 1000 * 10 / tape->stage_size; 3461 tape->max_stages = speed * 1000 * 10 / tape->stage_size;
3597 3462
3598 /* 3463 /* Limit memory use for pipeline to 10% of physical memory */
3599 * Limit memory use for pipeline to 10% of physical memory
3600 */
3601 si_meminfo(&si); 3464 si_meminfo(&si);
3602 if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10) 3465 if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10)
3603 tape->max_stages = si.totalram * si.mem_unit / (10 * tape->stage_size); 3466 tape->max_stages = si.totalram * si.mem_unit / (10 * tape->stage_size);
@@ -3617,8 +3480,8 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
3617 t = t1; 3480 t = t1;
3618 3481
3619 /* 3482 /*
3620 * Ensure that the number we got makes sense; limit 3483 * Ensure that the number we got makes sense; limit it within
3621 * it within IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX. 3484 * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
3622 */ 3485 */
3623 tape->best_dsc_rw_freq = max_t(unsigned long, 3486 tape->best_dsc_rw_freq = max_t(unsigned long,
3624 min_t(unsigned long, t, IDETAPE_DSC_RW_MAX), 3487 min_t(unsigned long, t, IDETAPE_DSC_RW_MAX),
@@ -3706,9 +3569,7 @@ static ide_driver_t idetape_driver = {
3706#endif 3569#endif
3707}; 3570};
3708 3571
3709/* 3572/* Our character device supporting functions, passed to register_chrdev. */
3710 * Our character device supporting functions, passed to register_chrdev.
3711 */
3712static const struct file_operations idetape_fops = { 3573static const struct file_operations idetape_fops = {
3713 .owner = THIS_MODULE, 3574 .owner = THIS_MODULE,
3714 .read = idetape_chrdev_read, 3575 .read = idetape_chrdev_read,