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Commit 3c98bf34 authored by Borislav Petkov's avatar Borislav Petkov Committed by Bartlomiej Zolnierkiewicz
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ide-tape: cleanup and fix comments 

Also, remove redundant ones and cleanup whitespace.

Bart:
- minor fixups
Signed-off-by: default avatarBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
parent 8d06bfad
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Showing with 271 additions and 410 deletions
drivers/ide/ide-tape.c
View file @ 3c98bf34
...@@ -75,37 +75,34 @@ enum { ...@@ -75,37 +75,34 @@ enum {
/* /*
* Pipelined mode parameters. * Pipelined mode parameters.
* *
* We try to use the minimum number of stages which is enough to * We try to use the minimum number of stages which is enough to keep the tape
* keep the tape constantly streaming. To accomplish that, we implement * constantly streaming. To accomplish that, we implement a feedback loop around
* a feedback loop around the maximum number of stages: * the maximum number of stages:
* *
* We start from MIN maximum stages (we will not even use MIN stages * We start from MIN maximum stages (we will not even use MIN stages if we don't
* if we don't need them), increment it by RATE*(MAX-MIN) * need them), increment it by RATE*(MAX-MIN) whenever we sense that the
* whenever we sense that the pipeline is empty, until we reach * pipeline is empty, until we reach the optimum value or until we reach MAX.
* the optimum value or until we reach MAX.
* *
* Setting the following parameter to 0 is illegal: the pipelined mode * Setting the following parameter to 0 is illegal: the pipelined mode cannot be
* cannot be disabled (idetape_calculate_speeds() divides by * disabled (idetape_calculate_speeds() divides by tape->max_stages.)
* tape->max_stages.)
*/ */
#define IDETAPE_MIN_PIPELINE_STAGES 1 #define IDETAPE_MIN_PIPELINE_STAGES 1
#define IDETAPE_MAX_PIPELINE_STAGES 400 #define IDETAPE_MAX_PIPELINE_STAGES 400
#define IDETAPE_INCREASE_STAGES_RATE 20 #define IDETAPE_INCREASE_STAGES_RATE 20
/* /*
* After each failed packet command we issue a request sense command * After each failed packet command we issue a request sense command and retry
* and retry the packet command IDETAPE_MAX_PC_RETRIES times. * the packet command IDETAPE_MAX_PC_RETRIES times.
* *
* Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries. * Setting IDETAPE_MAX_PC_RETRIES to 0 will disable retries.
*/ */
#define IDETAPE_MAX_PC_RETRIES 3 #define IDETAPE_MAX_PC_RETRIES 3
/* /*
* With each packet command, we allocate a buffer of * With each packet command, we allocate a buffer of IDETAPE_PC_BUFFER_SIZE
* IDETAPE_PC_BUFFER_SIZE bytes. This is used for several packet * bytes. This is used for several packet commands (Not for READ/WRITE commands)
* commands (Not for READ/WRITE commands).
*/ */
#define IDETAPE_PC_BUFFER_SIZE 256 #define IDETAPE_PC_BUFFER_SIZE 256
...@@ -124,48 +121,39 @@ enum { ...@@ -124,48 +121,39 @@ enum {
#define IDETAPE_WAIT_CMD (900*HZ) #define IDETAPE_WAIT_CMD (900*HZ)
/* /*
* The following parameter is used to select the point in the internal * The following parameter is used to select the point in the internal tape fifo
* tape fifo in which we will start to refill the buffer. Decreasing * in which we will start to refill the buffer. Decreasing the following
* the following parameter will improve the system's latency and * parameter will improve the system's latency and interactive response, while
* interactive response, while using a high value might improve system * using a high value might improve system throughput.
* throughput.
*/ */
#define IDETAPE_FIFO_THRESHOLD 2 #define IDETAPE_FIFO_THRESHOLD 2
/* /*
* DSC polling parameters. * DSC polling parameters.
* *
* Polling for DSC (a single bit in the status register) is a very * Polling for DSC (a single bit in the status register) is a very important
* important function in ide-tape. There are two cases in which we * function in ide-tape. There are two cases in which we poll for DSC:
* poll for DSC:
* *
* 1. Before a read/write packet command, to ensure that we * 1. Before a read/write packet command, to ensure that we can transfer data
* can transfer data from/to the tape's data buffers, without * from/to the tape's data buffers, without causing an actual media access.
* causing an actual media access. In case the tape is not * In case the tape is not ready yet, we take out our request from the device
* ready yet, we take out our request from the device * request queue, so that ide.c could service requests from the other device
* request queue, so that ide.c will service requests from * on the same interface in the meantime.
* the other device on the same interface meanwhile.
* *
* 2. After the successful initialization of a "media access * 2. After the successful initialization of a "media access packet command",
* packet command", which is a command which can take a long * which is a command that can take a long time to complete (the interval can
* time to complete (it can be several seconds or even an hour). * range from several seconds to even an hour). Again, we postpone our request
* in the middle to free the bus for the other device. The polling frequency
* here should be lower than the read/write frequency since those media access
* commands are slow. We start from a "fast" frequency - IDETAPE_DSC_MA_FAST
* (1 second), and if we don't receive DSC after IDETAPE_DSC_MA_THRESHOLD
* (5 min), we switch it to a lower frequency - IDETAPE_DSC_MA_SLOW (1 min).
* *
* Again, we postpone our request in the middle to free the bus * We also set a timeout for the timer, in case something goes wrong. The
* for the other device. The polling frequency here should be * timeout should be longer then the maximum execution time of a tape operation.
* lower than the read/write frequency since those media access
* commands are slow. We start from a "fast" frequency -
* IDETAPE_DSC_MA_FAST (one second), and if we don't receive DSC
* after IDETAPE_DSC_MA_THRESHOLD (5 minutes), we switch it to a
* lower frequency - IDETAPE_DSC_MA_SLOW (1 minute).
*
* We also set a timeout for the timer, in case something goes wrong.
* The timeout should be longer then the maximum execution time of a
* tape operation.
*/
/*
* DSC timings.
*/ */
/* DSC timings. */
#define IDETAPE_DSC_RW_MIN 5*HZ/100 /* 50 msec */ #define IDETAPE_DSC_RW_MIN 5*HZ/100 /* 50 msec */
#define IDETAPE_DSC_RW_MAX 40*HZ/100 /* 400 msec */ #define IDETAPE_DSC_RW_MAX 40*HZ/100 /* 400 msec */
#define IDETAPE_DSC_RW_TIMEOUT 2*60*HZ /* 2 minutes */ #define IDETAPE_DSC_RW_TIMEOUT 2*60*HZ /* 2 minutes */
...@@ -176,15 +164,9 @@ enum { ...@@ -176,15 +164,9 @@ enum {
/*************************** End of tunable parameters ***********************/ /*************************** End of tunable parameters ***********************/
/* /* Read/Write error simulation */
* Read/Write error simulation
*/
#define SIMULATE_ERRORS 0 #define SIMULATE_ERRORS 0
/*
* For general magnetic tape device compatibility.
*/
/* tape directions */ /* tape directions */
enum { enum {
IDETAPE_DIR_NONE = (1 << 0), IDETAPE_DIR_NONE = (1 << 0),
...@@ -199,24 +181,32 @@ struct idetape_bh { ...@@ -199,24 +181,32 @@ struct idetape_bh {
char *b_data; char *b_data;
}; };
/*
* Our view of a packet command.
*/
typedef struct idetape_packet_command_s { typedef struct idetape_packet_command_s {
u8 c[12]; /* Actual packet bytes */ /* Actual packet bytes */
int retries; /* On each retry, we increment retries */ u8 c[12];
int error; /* Error code */ /* On each retry, we increment retries */
int request_transfer; /* Bytes to transfer */ int retries;
int actually_transferred; /* Bytes actually transferred */ /* Error code */
int buffer_size; /* Size of our data buffer */ int error;
/* Bytes to transfer */
int request_transfer;
/* Bytes actually transferred */
int actually_transferred;
/* Size of our data buffer */
int buffer_size;
struct idetape_bh *bh; struct idetape_bh *bh;
char *b_data; char *b_data;
int b_count; int b_count;
u8 *buffer; /* Data buffer */ /* Data buffer */
u8 *current_position; /* Pointer into the above buffer */ u8 *buffer;
ide_startstop_t (*callback) (ide_drive_t *); /* Called when this packet command is completed */ /* Pointer into the above buffer */
u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE]; /* Temporary buffer */ u8 *current_position;
unsigned long flags; /* Status/Action bit flags: long for set_bit */ /* Called when this packet command is completed */
ide_startstop_t (*callback) (ide_drive_t *);
/* Temporary buffer */
u8 pc_buffer[IDETAPE_PC_BUFFER_SIZE];
/* Status/Action bit flags: long for set_bit */
unsigned long flags;
} idetape_pc_t; } idetape_pc_t;
/* /*
...@@ -235,9 +225,7 @@ typedef struct idetape_packet_command_s { ...@@ -235,9 +225,7 @@ typedef struct idetape_packet_command_s {
/* Data direction */ /* Data direction */
#define PC_WRITING 5 #define PC_WRITING 5
/* /* A pipeline stage. */
* A pipeline stage.
*/
typedef struct idetape_stage_s { typedef struct idetape_stage_s {
struct request rq; /* The corresponding request */ struct request rq; /* The corresponding request */
struct idetape_bh *bh; /* The data buffers */ struct idetape_bh *bh; /* The data buffers */
...@@ -245,9 +233,8 @@ typedef struct idetape_stage_s { ...@@ -245,9 +233,8 @@ typedef struct idetape_stage_s {
} idetape_stage_t; } idetape_stage_t;
/* /*
* Most of our global data which we need to save even as we leave the * Most of our global data which we need to save even as we leave the driver due
* driver due to an interrupt or a timer event is stored in a variable * to an interrupt or a timer event is stored in the struct defined below.
* of type idetape_tape_t, defined below.
*/ */
typedef struct ide_tape_obj { typedef struct ide_tape_obj {
ide_drive_t *drive; ide_drive_t *drive;
...@@ -283,15 +270,14 @@ typedef struct ide_tape_obj { ...@@ -283,15 +270,14 @@ typedef struct ide_tape_obj {
int rq_stack_index; int rq_stack_index;
/* /*
* DSC polling variables. * DSC polling variables.
* *
* While polling for DSC we use postponed_rq to postpone the * While polling for DSC we use postponed_rq to postpone the current
* current request so that ide.c will be able to service * request so that ide.c will be able to service pending requests on the
* pending requests on the other device. Note that at most * other device. Note that at most we will have only one DSC (usually
* we will have only one DSC (usually data transfer) request * data transfer) request in the device request queue. Additional
* in the device request queue. Additional requests can be * requests can be queued in our internal pipeline, but they will be
* queued in our internal pipeline, but they will be visible * visible to ide.c only one at a time.
* to ide.c only one at a time.
*/ */
struct request *postponed_rq; struct request *postponed_rq;
/* The time in which we started polling for DSC */ /* The time in which we started polling for DSC */
...@@ -303,21 +289,15 @@ typedef struct ide_tape_obj { ...@@ -303,21 +289,15 @@ typedef struct ide_tape_obj {
unsigned long dsc_poll_freq; unsigned long dsc_poll_freq;
unsigned long dsc_timeout; unsigned long dsc_timeout;
/* /* Read position information */
* Read position information
*/
u8 partition; u8 partition;
/* Current block */ /* Current block */
unsigned int first_frame; unsigned int first_frame;
/* /* Last error information */
* Last error information
*/
u8 sense_key, asc, ascq; u8 sense_key, asc, ascq;
/* /* Character device operation */
* Character device operation
*/
unsigned int minor; unsigned int minor;
/* device name */ /* device name */
char name[4]; char name[4];
...@@ -332,33 +312,30 @@ typedef struct ide_tape_obj { ...@@ -332,33 +312,30 @@ typedef struct ide_tape_obj {
u8 caps[20]; u8 caps[20];
/* /*
* Active data transfer request parameters. * Active data transfer request parameters.
*
* At most, there is only one ide-tape originated data transfer
* request in the device request queue. This allows ide.c to
* easily service requests from the other device when we
* postpone our active request. In the pipelined operation
* mode, we use our internal pipeline structure to hold
* more data requests.
* *
* The data buffer size is chosen based on the tape's * At most, there is only one ide-tape originated data transfer request
* recommendation. * in the device request queue. This allows ide.c to easily service
* requests from the other device when we postpone our active request.
* In the pipelined operation mode, we use our internal pipeline
* structure to hold more data requests. The data buffer size is chosen
* based on the tape's recommendation.
*/ */
/* Ptr to the request which is waiting in the device request queue */ /* ptr to the request which is waiting in the device request queue */
struct request *active_data_rq; struct request *active_data_rq;
/* Data buffer size (chosen based on the tape's recommendation */ /* Data buffer size chosen based on the tape's recommendation */
int stage_size; int stage_size;
idetape_stage_t *merge_stage; idetape_stage_t *merge_stage;
int merge_stage_size; int merge_stage_size;
struct idetape_bh *bh; struct idetape_bh *bh;
char *b_data; char *b_data;
int b_count; int b_count;
/* /*
* Pipeline parameters. * Pipeline parameters.
* *
* To accomplish non-pipelined mode, we simply set the following * To accomplish non-pipelined mode, we simply set the following
* variables to zero (or NULL, where appropriate). * variables to zero (or NULL, where appropriate).
*/ */
/* Number of currently used stages */ /* Number of currently used stages */
int nr_stages; int nr_stages;
...@@ -385,9 +362,7 @@ typedef struct ide_tape_obj { ...@@ -385,9 +362,7 @@ typedef struct ide_tape_obj {
/* protects the ide-tape queue */ /* protects the ide-tape queue */
spinlock_t lock; spinlock_t lock;
/* /* Measures average tape speed */
* Measures average tape speed
*/
unsigned long avg_time; unsigned long avg_time;
int avg_size; int avg_size;
int avg_speed; int avg_speed;
...@@ -400,11 +375,9 @@ typedef struct ide_tape_obj { ...@@ -400,11 +375,9 @@ typedef struct ide_tape_obj {
char write_prot; char write_prot;
/* /*
* Limit the number of times a request can * Limit the number of times a request can be postponed, to avoid an
* be postponed, to avoid an infinite postpone * infinite postpone deadlock.
* deadlock.
*/ */
/* request postpone count limit */
int postpone_cnt; int postpone_cnt;
/* /*
...@@ -419,18 +392,14 @@ typedef struct ide_tape_obj { ...@@ -419,18 +392,14 @@ typedef struct ide_tape_obj {
int tape_head; int tape_head;
int last_tape_head; int last_tape_head;
/* /* Speed control at the tape buffers input/output */
* Speed control at the tape buffers input/output
*/
unsigned long insert_time; unsigned long insert_time;
int insert_size; int insert_size;
int insert_speed; int insert_speed;
int max_insert_speed; int max_insert_speed;
int measure_insert_time; int measure_insert_time;
/* /* Speed regulation negative feedback loop */
* Speed regulation negative feedback loop
*/
int speed_control; int speed_control;
int pipeline_head_speed; int pipeline_head_speed;
int controlled_pipeline_head_speed; int controlled_pipeline_head_speed;
...@@ -477,9 +446,7 @@ static void ide_tape_put(struct ide_tape_obj *tape) ...@@ -477,9 +446,7 @@ static void ide_tape_put(struct ide_tape_obj *tape)
mutex_unlock(&idetape_ref_mutex); mutex_unlock(&idetape_ref_mutex);
} }
/* /* Tape door status */
* Tape door status
*/
#define DOOR_UNLOCKED 0 #define DOOR_UNLOCKED 0
#define DOOR_LOCKED 1 #define DOOR_LOCKED 1
#define DOOR_EXPLICITLY_LOCKED 2 #define DOOR_EXPLICITLY_LOCKED 2
...@@ -499,30 +466,23 @@ static void ide_tape_put(struct ide_tape_obj *tape) ...@@ -499,30 +466,23 @@ static void ide_tape_put(struct ide_tape_obj *tape)
/* 0 = no tape is loaded, so we don't rewind after ejecting */ /* 0 = no tape is loaded, so we don't rewind after ejecting */
#define IDETAPE_MEDIUM_PRESENT 9 #define IDETAPE_MEDIUM_PRESENT 9
/* /* A define for the READ BUFFER command */
* Some defines for the READ BUFFER command
*/
#define IDETAPE_RETRIEVE_FAULTY_BLOCK 6 #define IDETAPE_RETRIEVE_FAULTY_BLOCK 6
/* /* Some defines for the SPACE command */
* Some defines for the SPACE command
*/
#define IDETAPE_SPACE_OVER_FILEMARK 1 #define IDETAPE_SPACE_OVER_FILEMARK 1
#define IDETAPE_SPACE_TO_EOD 3 #define IDETAPE_SPACE_TO_EOD 3
/* /* Some defines for the LOAD UNLOAD command */
* Some defines for the LOAD UNLOAD command
*/
#define IDETAPE_LU_LOAD_MASK 1 #define IDETAPE_LU_LOAD_MASK 1
#define IDETAPE_LU_RETENSION_MASK 2 #define IDETAPE_LU_RETENSION_MASK 2
#define IDETAPE_LU_EOT_MASK 4 #define IDETAPE_LU_EOT_MASK 4
/* /*
* Special requests for our block device strategy routine. * Special requests for our block device strategy routine.
* *
* In order to service a character device command, we add special * In order to service a character device command, we add special requests to
* requests to the tail of our block device request queue and wait * the tail of our block device request queue and wait for their completion.
* for their completion.
*/ */
enum { enum {
...@@ -533,10 +493,7 @@ enum { ...@@ -533,10 +493,7 @@ enum {
REQ_IDETAPE_READ_BUFFER = (1 << 4), REQ_IDETAPE_READ_BUFFER = (1 << 4),
}; };
/* /* Error codes returned in rq->errors to the higher part of the driver. */
* Error codes which are returned in rq->errors to the higher part
* of the driver.
*/
#define IDETAPE_ERROR_GENERAL 101 #define IDETAPE_ERROR_GENERAL 101
#define IDETAPE_ERROR_FILEMARK 102 #define IDETAPE_ERROR_FILEMARK 102
#define IDETAPE_ERROR_EOD 103 #define IDETAPE_ERROR_EOD 103
...@@ -560,8 +517,8 @@ struct idetape_id_gcw { ...@@ -560,8 +517,8 @@ struct idetape_id_gcw {
#define IDETAPE_CAPABILITIES_PAGE 0x2a #define IDETAPE_CAPABILITIES_PAGE 0x2a
/* /*
* The variables below are used for the character device interface. * The variables below are used for the character device interface. Additional
* Additional state variables are defined in our ide_drive_t structure. * state variables are defined in our ide_drive_t structure.
*/ */
static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES]; static struct ide_tape_obj * idetape_devs[MAX_HWIFS * MAX_DRIVES];
...@@ -579,10 +536,6 @@ static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i) ...@@ -579,10 +536,6 @@ static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
return tape; return tape;
} }
/*
* Function declarations
*
*/
static int idetape_chrdev_release (struct inode *inode, struct file *filp); static int idetape_chrdev_release (struct inode *inode, struct file *filp);
static void idetape_write_release (ide_drive_t *drive, unsigned int minor); static void idetape_write_release (ide_drive_t *drive, unsigned int minor);
...@@ -711,9 +664,6 @@ static struct request *idetape_next_rq_storage (ide_drive_t *drive) ...@@ -711,9 +664,6 @@ static struct request *idetape_next_rq_storage (ide_drive_t *drive)
return (&tape->rq_stack[tape->rq_stack_index++]); return (&tape->rq_stack[tape->rq_stack_index++]);
} }
/*
* idetape_init_pc initializes a packet command.
*/
static void idetape_init_pc (idetape_pc_t *pc) static void idetape_init_pc (idetape_pc_t *pc)
{ {
memset(pc->c, 0, 12); memset(pc->c, 0, 12);
...@@ -809,10 +759,7 @@ static void idetape_activate_next_stage(ide_drive_t *drive) ...@@ -809,10 +759,7 @@ static void idetape_activate_next_stage(ide_drive_t *drive)
tape->next_stage = stage->next; tape->next_stage = stage->next;
} }
/* /* Free a stage along with its related buffers completely. */
* idetape_kfree_stage calls kfree to completely free a stage, along with
* its related buffers.
*/
static void __idetape_kfree_stage (idetape_stage_t *stage) static void __idetape_kfree_stage (idetape_stage_t *stage)
{ {
struct idetape_bh *prev_bh, *bh = stage->bh; 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) ...@@ -840,8 +787,8 @@ static void idetape_kfree_stage (idetape_tape_t *tape, idetape_stage_t *stage)
} }
/* /*
* idetape_remove_stage_head removes tape->first_stage from the pipeline. * Remove tape->first_stage from the pipeline. The caller should avoid race
* The caller should avoid race conditions. * conditions.
*/ */
static void idetape_remove_stage_head (ide_drive_t *drive) static void idetape_remove_stage_head (ide_drive_t *drive)
{ {
...@@ -899,8 +846,8 @@ static void idetape_abort_pipeline(ide_drive_t *drive, ...@@ -899,8 +846,8 @@ static void idetape_abort_pipeline(ide_drive_t *drive,
} }
/* /*
* idetape_end_request is used to finish servicing a request, and to * Finish servicing a request and insert a pending pipeline request into the
* insert a pending pipeline request into the main device queue. * main device queue.
*/ */
static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects) static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
{ {
...@@ -951,9 +898,7 @@ static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects) ...@@ -951,9 +898,7 @@ static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
if (tape->next_stage != NULL) { if (tape->next_stage != NULL) {
idetape_activate_next_stage(drive); idetape_activate_next_stage(drive);
/* /* Insert the next request into the request queue. */
* Insert the next request into the request queue.
*/
(void)ide_do_drive_cmd(drive, tape->active_data_rq, (void)ide_do_drive_cmd(drive, tape->active_data_rq,
ide_end); ide_end);
} else if (!error) { } else if (!error) {
...@@ -1020,23 +965,19 @@ static void idetape_init_rq(struct request *rq, u8 cmd) ...@@ -1020,23 +965,19 @@ static void idetape_init_rq(struct request *rq, u8 cmd)
} }
/* /*
* idetape_queue_pc_head generates a new packet command request in front * Generate a new packet command request in front of the request queue, before
* of the request queue, before the current request, so that it will be * the current request, so that it will be processed immediately, on the next
* processed immediately, on the next pass through the driver. * pass through the driver. The function below is called from the request
* * handling part of the driver (the "bottom" part). Safe storage for the request
* idetape_queue_pc_head is called from the request handling part of * should be allocated with ide_tape_next_{pc,rq}_storage() prior to that.
* the driver (the "bottom" part). Safe storage for the request should
* be allocated with idetape_next_pc_storage and idetape_next_rq_storage
* before calling idetape_queue_pc_head.
* *
* Memory for those requests is pre-allocated at initialization time, and * Memory for those requests is pre-allocated at initialization time, and is
* is limited to IDETAPE_PC_STACK requests. We assume that we have enough * limited to IDETAPE_PC_STACK requests. We assume that we have enough space for
* space for the maximum possible number of inter-dependent packet commands. * the maximum possible number of inter-dependent packet commands.
* *
* The higher level of the driver - The ioctl handler and the character * The higher level of the driver - The ioctl handler and the character device
* device handling functions should queue request to the lower level part * handling functions should queue request to the lower level part and wait for
* and wait for their completion using idetape_queue_pc_tail or * their completion using idetape_queue_pc_tail or idetape_queue_rw_tail.
* idetape_queue_rw_tail.
*/ */
static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq) static void idetape_queue_pc_head (ide_drive_t *drive, idetape_pc_t *pc,struct request *rq)
{ {
...@@ -1069,9 +1010,8 @@ static ide_startstop_t idetape_retry_pc (ide_drive_t *drive) ...@@ -1069,9 +1010,8 @@ static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
} }
/* /*
* idetape_postpone_request postpones the current request so that * Postpone the current request so that ide.c will be able to service requests
* ide.c will be able to service requests from another device on * from another device on the same hwgroup while we are polling for DSC.
* the same hwgroup while we are polling for DSC.
*/ */
static void idetape_postpone_request (ide_drive_t *drive) static void idetape_postpone_request (ide_drive_t *drive)
{ {
...@@ -1258,46 +1198,40 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive) ...@@ -1258,46 +1198,40 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
} }
/* /*
* Packet Command Interface * Packet Command Interface
* *
* The current Packet Command is available in tape->pc, and will not * The current Packet Command is available in tape->pc, and will not change
* change until we finish handling it. Each packet command is associated * until we finish handling it. Each packet command is associated with a
* with a callback function that will be called when the command is * callback function that will be called when the command is finished.
* finished.
* *
* The handling will be done in three stages: * The handling will be done in three stages:
* *
* 1. idetape_issue_pc will send the packet command to the * 1. idetape_issue_pc will send the packet command to the drive, and will set
* drive, and will set the interrupt handler to idetape_pc_intr. * the interrupt handler to idetape_pc_intr.
* *
* 2. On each interrupt, idetape_pc_intr will be called. This step * 2. On each interrupt, idetape_pc_intr will be called. This step will be
* will be repeated until the device signals us that no more * repeated until the device signals us that no more interrupts will be issued.
* interrupts will be issued.
* *
* 3. ATAPI Tape media access commands have immediate status with a * 3. ATAPI Tape media access commands have immediate status with a delayed
* delayed process. In case of a successful initiation of a * process. In case of a successful initiation of a media access packet command,
* media access packet command, the DSC bit will be set when the * the DSC bit will be set when the actual execution of the command is finished.
* actual execution of the command is finished. * Since the tape drive will not issue an interrupt, we have to poll for this
* Since the tape drive will not issue an interrupt, we have to * event. In this case, we define the request as "low priority request" by
* poll for this event. In this case, we define the request as * setting rq_status to IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and
* "low priority request" by setting rq_status to * exit the driver.
* IDETAPE_RQ_POSTPONED, set a timer to poll for DSC and exit
* the driver.
* *
* ide.c will then give higher priority to requests which * ide.c will then give higher priority to requests which originate from the
* originate from the other device, until will change rq_status * other device, until will change rq_status to RQ_ACTIVE.
* to RQ_ACTIVE.
* *
* 4. When the packet command is finished, it will be checked for errors. * 4. When the packet command is finished, it will be checked for errors.
* *
* 5. In case an error was found, we queue a request sense packet * 5. In case an error was found, we queue a request sense packet command in
* command in front of the request queue and retry the operation * front of the request queue and retry the operation up to
* up to IDETAPE_MAX_PC_RETRIES times. * IDETAPE_MAX_PC_RETRIES times.
*
* 6. In case no error was found, or we decided to give up and not
* to retry again, the callback function will be called and then
* we will handle the next request.
* *
* 6. In case no error was found, or we decided to give up and not to retry
* again, the callback function will be called and then we will handle the next
* request.
*/ */
static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive) static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
{ {
...@@ -1363,9 +1297,9 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive, idetape_pc_t *pc) ...@@ -1363,9 +1297,9 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive, idetape_pc_t *pc)
if (pc->retries > IDETAPE_MAX_PC_RETRIES || if (pc->retries > IDETAPE_MAX_PC_RETRIES ||
test_bit(PC_ABORT, &pc->flags)) { test_bit(PC_ABORT, &pc->flags)) {
/* /*
* We will "abort" retrying a packet command in case * We will "abort" retrying a packet command in case legitimate
* a legitimate error code was received (crossing a * error code was received (crossing a filemark, or end of the
* filemark, or end of the media, for example). * media, for example).
*/ */
if (!test_bit(PC_ABORT, &pc->flags)) { if (!test_bit(PC_ABORT, &pc->flags)) {
if (!(pc->c[0] == TEST_UNIT_READY && 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) ...@@ -1416,9 +1350,6 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive, idetape_pc_t *pc)
} }
} }
/*
* General packet command callback function.
*/
static ide_startstop_t idetape_pc_callback (ide_drive_t *drive) static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
{ {
idetape_tape_t *tape = drive->driver_data; idetape_tape_t *tape = drive->driver_data;
...@@ -1429,15 +1360,14 @@ static ide_startstop_t idetape_pc_callback (ide_drive_t *drive) ...@@ -1429,15 +1360,14 @@ static ide_startstop_t idetape_pc_callback (ide_drive_t *drive)
return ide_stopped; return ide_stopped;
} }
/* /* A mode sense command is used to "sense" tape parameters. */
* A mode sense command is used to "sense" tape parameters.
*/
static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code) static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
{ {
idetape_init_pc(pc); idetape_init_pc(pc);
pc->c[0] = MODE_SENSE; pc->c[0] = MODE_SENSE;
if (page_code != IDETAPE_BLOCK_DESCRIPTOR) if (page_code != IDETAPE_BLOCK_DESCRIPTOR)
pc->c[1] = 8; /* DBD = 1 - Don't return block descriptors */ /* DBD = 1 - Don't return block descriptors */
pc->c[1] = 8;
pc->c[2] = page_code; pc->c[2] = page_code;
/* /*
* Changed pc->c[3] to 0 (255 will at best return unused info). * 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) ...@@ -1447,7 +1377,8 @@ static void idetape_create_mode_sense_cmd (idetape_pc_t *pc, u8 page_code)
* and return an error when 255 is used. * and return an error when 255 is used.
*/ */
pc->c[3] = 0; pc->c[3] = 0;
pc->c[4] = 255; /* (We will just discard data in that case) */ /* We will just discard data in that case */
pc->c[4] = 255;
if (page_code == IDETAPE_BLOCK_DESCRIPTOR) if (page_code == IDETAPE_BLOCK_DESCRIPTOR)
pc->request_transfer = 12; pc->request_transfer = 12;
else if (page_code == IDETAPE_CAPABILITIES_PAGE) 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 ...@@ -1619,9 +1550,6 @@ static void idetape_create_write_cmd(idetape_tape_t *tape, idetape_pc_t *pc, uns
set_bit(PC_DMA_RECOMMENDED, &pc->flags); set_bit(PC_DMA_RECOMMENDED, &pc->flags);
} }
/*
* idetape_do_request is our request handling function.
*/
static ide_startstop_t idetape_do_request(ide_drive_t *drive, static ide_startstop_t idetape_do_request(ide_drive_t *drive,
struct request *rq, sector_t block) struct request *rq, sector_t block)
{ {
...@@ -1635,18 +1563,14 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive, ...@@ -1635,18 +1563,14 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
rq->sector, rq->nr_sectors, rq->current_nr_sectors); rq->sector, rq->nr_sectors, rq->current_nr_sectors);
if (!blk_special_request(rq)) { if (!blk_special_request(rq)) {
/* /* We do not support buffer cache originated requests. */
* We do not support buffer cache originated requests.
*/
printk(KERN_NOTICE "ide-tape: %s: Unsupported request in " printk(KERN_NOTICE "ide-tape: %s: Unsupported request in "
"request queue (%d)\n", drive->name, rq->cmd_type); "request queue (%d)\n", drive->name, rq->cmd_type);
ide_end_request(drive, 0, 0); ide_end_request(drive, 0, 0);
return ide_stopped; return ide_stopped;
} }
/* /* Retry a failed packet command */
* Retry a failed packet command
*/
if (tape->failed_pc != NULL && if (tape->failed_pc != NULL &&
tape->pc->c[0] == REQUEST_SENSE) { tape->pc->c[0] == REQUEST_SENSE) {
return idetape_issue_pc(drive, tape->failed_pc); return idetape_issue_pc(drive, tape->failed_pc);
...@@ -1733,9 +1657,7 @@ out: ...@@ -1733,9 +1657,7 @@ out:
return idetape_issue_pc(drive, pc); return idetape_issue_pc(drive, pc);
} }
/* /* Pipeline related functions */
* Pipeline related functions
*/
static inline int idetape_pipeline_active (idetape_tape_t *tape) static inline int idetape_pipeline_active (idetape_tape_t *tape)
{ {
int rc1, rc2; int rc1, rc2;
...@@ -1746,16 +1668,16 @@ static inline int idetape_pipeline_active (idetape_tape_t *tape) ...@@ -1746,16 +1668,16 @@ static inline int idetape_pipeline_active (idetape_tape_t *tape)
} }
/* /*
* idetape_kmalloc_stage uses __get_free_page to allocate a pipeline * The function below uses __get_free_page to allocate a pipeline stage, along
* stage, along with all the necessary small buffers which together make * with all the necessary small buffers which together make a buffer of size
* a buffer of size tape->stage_size (or a bit more). We attempt to * tape->stage_size (or a bit more). We attempt to combine sequential pages as
* combine sequential pages as much as possible. * much as possible.
* *
* Returns a pointer to the new allocated stage, or NULL if we * It returns a pointer to the new allocated stage, or NULL if we can't (or
* can't (or don't want to) allocate a stage. * don't want to) allocate a stage.
* *
* Pipeline stages are optional and are used to increase performance. * Pipeline stages are optional and are used to increase performance. If we
* If we can't allocate them, we'll manage without them. * can't allocate them, we'll manage without them.
*/ */
static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear) static idetape_stage_t *__idetape_kmalloc_stage (idetape_tape_t *tape, int full, int clear)
{ {
...@@ -1913,9 +1835,7 @@ static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage ...@@ -1913,9 +1835,7 @@ static void idetape_switch_buffers (idetape_tape_t *tape, idetape_stage_t *stage
idetape_init_merge_stage(tape); idetape_init_merge_stage(tape);
} }
/* /* Add a new stage at the end of the pipeline. */
* idetape_add_stage_tail adds a new stage at the end of the pipeline.
*/
static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage) static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
{ {
idetape_tape_t *tape = drive->driver_data; 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) ...@@ -1937,12 +1857,9 @@ static void idetape_add_stage_tail (ide_drive_t *drive,idetape_stage_t *stage)
spin_unlock_irqrestore(&tape->lock, flags); spin_unlock_irqrestore(&tape->lock, flags);
} }
/* /* Install a completion in a pending request and sleep until it is serviced. The
* idetape_wait_for_request installs a completion in a pending request * caller should ensure that the request will not be serviced before we install
* and sleeps until it is serviced. * the completion (usually by disabling interrupts).
*
* The caller should ensure that the request will not be serviced
* before we install the completion (usually by disabling interrupts).
*/ */
static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq) static void idetape_wait_for_request (ide_drive_t *drive, struct request *rq)
{ {
...@@ -1996,12 +1913,8 @@ static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive) ...@@ -1996,12 +1913,8 @@ static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
} }
/* /*
* idetape_create_write_filemark_cmd will: * Write a filemark if write_filemark=1. Flush the device buffers without
* * writing a filemark otherwise.
* 1. Write a filemark if write_filemark=1.
* 2. Flush the device buffers without writing a filemark
* if write_filemark=0.
*
*/ */
static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark) static void idetape_create_write_filemark_cmd (ide_drive_t *drive, idetape_pc_t *pc,int write_filemark)
{ {
...@@ -2020,24 +1933,17 @@ static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc) ...@@ -2020,24 +1933,17 @@ static void idetape_create_test_unit_ready_cmd(idetape_pc_t *pc)
} }
/* /*
* idetape_queue_pc_tail is based on the following functions: * We add a special packet command request to the tail of the request queue, and
* * wait for it to be serviced. This is not to be called from within the request
* ide_do_drive_cmd from ide.c * handling part of the driver! We allocate here data on the stack and it is
* cdrom_queue_request and cdrom_queue_packet_command from ide-cd.c * valid until the request is finished. This is not the case for the bottom part
* * of the driver, where we are always leaving the functions to wait for an
* We add a special packet command request to the tail of the request * interrupt or a timer event.
* queue, and wait for it to be serviced.
* *
* This is not to be called from within the request handling part * From the bottom part of the driver, we should allocate safe memory using
* of the driver ! We allocate here data in the stack, and it is valid * idetape_next_pc_storage() and ide_tape_next_rq_storage(), and add the request
* until the request is finished. This is not the case for the bottom * to the request list without waiting for it to be serviced! In that case, we
* part of the driver, where we are always leaving the functions to wait * usually use idetape_queue_pc_head().
* for an interrupt or a timer event.
*
* From the bottom part of the driver, we should allocate safe memory
* using idetape_next_pc_storage and idetape_next_rq_storage, and add
* the request to the request list without waiting for it to be serviced !
* In that case, we usually use idetape_queue_pc_head.
*/ */
static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc) static int __idetape_queue_pc_tail (ide_drive_t *drive, idetape_pc_t *pc)
{ {
...@@ -2065,9 +1971,7 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout) ...@@ -2065,9 +1971,7 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
idetape_pc_t pc; idetape_pc_t pc;
int load_attempted = 0; int load_attempted = 0;
/* /* Wait for the tape to become ready */
* Wait for the tape to become ready
*/
set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags); set_bit(IDETAPE_MEDIUM_PRESENT, &tape->flags);
timeout += jiffies; timeout += jiffies;
while (time_before(jiffies, timeout)) { while (time_before(jiffies, timeout)) {
...@@ -2075,7 +1979,8 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout) ...@@ -2075,7 +1979,8 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
if (!__idetape_queue_pc_tail(drive, &pc)) if (!__idetape_queue_pc_tail(drive, &pc))
return 0; return 0;
if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2) if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
|| (tape->asc == 0x3A)) { /* no media */ || (tape->asc == 0x3A)) {
/* no media */
if (load_attempted) if (load_attempted)
return -ENOMEDIUM; return -ENOMEDIUM;
idetape_create_load_unload_cmd(drive, &pc, IDETAPE_LU_LOAD_MASK); 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) ...@@ -2203,13 +2108,10 @@ static int __idetape_discard_read_pipeline (ide_drive_t *drive)
} }
/* /*
* idetape_position_tape positions the tape to the requested block * Position the tape to the requested block using the LOCATE packet command.
* using the LOCATE packet command. A READ POSITION command is then * A READ POSITION command is then issued to check where we are positioned. Like
* issued to check where we are positioned. * all higher level operations, we queue the commands at the tail of the request
* * queue and wait for their completion.
* Like all higher level operations, we queue the commands at the tail
* of the request queue and wait for their completion.
*
*/ */
static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip) static int idetape_position_tape (ide_drive_t *drive, unsigned int block, u8 partition, int skip)
{ {
...@@ -2247,8 +2149,8 @@ static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_posit ...@@ -2247,8 +2149,8 @@ static void idetape_discard_read_pipeline (ide_drive_t *drive, int restore_posit
} }
/* /*
* idetape_queue_rw_tail generates a read/write request for the block * Generate a read/write request for the block device interface and wait for it
* device interface and wait for it to be serviced. * to be serviced.
*/ */
static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh) static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks, struct idetape_bh *bh)
{ {
...@@ -2343,15 +2245,15 @@ static void idetape_wait_first_stage (ide_drive_t *drive) ...@@ -2343,15 +2245,15 @@ static void idetape_wait_first_stage (ide_drive_t *drive)
} }
/* /*
* idetape_add_chrdev_write_request tries to add a character device * Try to add a character device originated write request to our pipeline. In
* originated write request to our pipeline. In case we don't succeed, * case we don't succeed, we revert to non-pipelined operation mode for this
* we revert to non-pipelined operation mode for this request. * request. In order to accomplish that, we
* *
* 1. Try to allocate a new pipeline stage. * 1. Try to allocate a new pipeline stage.
* 2. If we can't, wait for more and more requests to be serviced * 2. If we can't, wait for more and more requests to be serviced and try again
* and try again each time. * each time.
* 3. If we still can't allocate a stage, fallback to * 3. If we still can't allocate a stage, fallback to non-pipelined operation
* non-pipelined operation mode for this request. * mode for this request.
*/ */
static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks) static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
{ {
...@@ -2362,10 +2264,7 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks) ...@@ -2362,10 +2264,7 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
debug_log(DBG_CHRDEV, "Enter %s\n", __func__); debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
/* /* Attempt to allocate a new stage. Beware possible race conditions. */
* Attempt to allocate a new stage.
* Pay special attention to possible race conditions.
*/
while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) { while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
spin_lock_irqsave(&tape->lock, flags); spin_lock_irqsave(&tape->lock, flags);
if (idetape_pipeline_active(tape)) { if (idetape_pipeline_active(tape)) {
...@@ -2377,8 +2276,8 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks) ...@@ -2377,8 +2276,8 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
if (idetape_pipeline_active(tape)) if (idetape_pipeline_active(tape))
continue; continue;
/* /*
* Linux is short on memory. Fallback to * The machine is short on memory. Fallback to non-
* non-pipelined operation mode for this request. * pipelined operation mode for this request.
*/ */
return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh); return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks, tape->merge_stage->bh);
} }
...@@ -2395,11 +2294,11 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks) ...@@ -2395,11 +2294,11 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
idetape_calculate_speeds(drive); idetape_calculate_speeds(drive);
/* /*
* Estimate whether the tape has stopped writing by checking * Estimate whether the tape has stopped writing by checking if our
* if our write pipeline is currently empty. If we are not * write pipeline is currently empty. If we are not writing anymore,
* writing anymore, wait for the pipeline to be full enough * wait for the pipeline to be almost completely full (90%) before
* (90%) before starting to service requests, so that we will * starting to service requests, so that we will be able to keep up with
* be able to keep up with the higher speeds of the tape. * the higher speeds of the tape.
*/ */
if (!idetape_pipeline_active(tape)) { if (!idetape_pipeline_active(tape)) {
if (tape->nr_stages >= tape->max_stages * 9 / 10 || 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) ...@@ -2420,8 +2319,8 @@ static int idetape_add_chrdev_write_request (ide_drive_t *drive, int blocks)
} }
/* /*
* idetape_wait_for_pipeline will wait until all pending pipeline * Wait until all pending pipeline requests are serviced. Typically called on
* requests are serviced. Typically called on device close. * device close.
*/ */
static void idetape_wait_for_pipeline (ide_drive_t *drive) static void idetape_wait_for_pipeline (ide_drive_t *drive)
{ {
...@@ -2490,10 +2389,10 @@ static void idetape_empty_write_pipeline (ide_drive_t *drive) ...@@ -2490,10 +2389,10 @@ static void idetape_empty_write_pipeline (ide_drive_t *drive)
tape->chrdev_dir = IDETAPE_DIR_NONE; tape->chrdev_dir = IDETAPE_DIR_NONE;
/* /*
* On the next backup, perform the feedback loop again. * On the next backup, perform the feedback loop again. (I don't want to
* (I don't want to keep sense information between backups, * keep sense information between backups, as some systems are
* as some systems are constantly on, and the system load * constantly on, and the system load can be totally different on the
* can be totally different on the next backup). * next backup).
*/ */
tape->max_stages = tape->min_pipeline; tape->max_stages = tape->min_pipeline;
if (tape->first_stage != NULL || if (tape->first_stage != NULL ||
...@@ -2545,11 +2444,10 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages) ...@@ -2545,11 +2444,10 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages)
tape->chrdev_dir = IDETAPE_DIR_READ; tape->chrdev_dir = IDETAPE_DIR_READ;
/* /*
* Issue a read 0 command to ensure that DSC handshake * Issue a read 0 command to ensure that DSC handshake is
* is switched from completion mode to buffer available * switched from completion mode to buffer available mode.
* mode. * No point in issuing this if DSC overlap isn't supported, some
* No point in issuing this if DSC overlap isn't supported, * drives (Seagate STT3401A) will return an error.
* some drives (Seagate STT3401A) will return an error.
*/ */
if (drive->dsc_overlap) { if (drive->dsc_overlap) {
bytes_read = idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, 0, tape->merge_stage->bh); 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) ...@@ -2590,9 +2488,8 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages)
} }
/* /*
* idetape_add_chrdev_read_request is called from idetape_chrdev_read * Called from idetape_chrdev_read() to service a character device read request
* to service a character device read request and add read-ahead * and add read-ahead requests to our pipeline.
* requests to our pipeline.
*/ */
static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks) static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
{ {
...@@ -2603,16 +2500,11 @@ static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks) ...@@ -2603,16 +2500,11 @@ static int idetape_add_chrdev_read_request (ide_drive_t *drive,int blocks)
debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks); debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
/* /* If we are at a filemark, return a read length of 0 */
* If we are at a filemark, return a read length of 0
*/
if (test_bit(IDETAPE_FILEMARK, &tape->flags)) if (test_bit(IDETAPE_FILEMARK, &tape->flags))
return 0; return 0;
/* /* Wait for the next block to reach the head of the pipeline. */
* Wait for the next block to be available at the head
* of the pipeline
*/
idetape_init_read(drive, tape->max_stages); idetape_init_read(drive, tape->max_stages);
if (tape->first_stage == NULL) { if (tape->first_stage == NULL) {
if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags)) if (test_bit(IDETAPE_PIPELINE_ERROR, &tape->flags))
...@@ -2651,7 +2543,7 @@ static void idetape_pad_zeros (ide_drive_t *drive, int bcount) ...@@ -2651,7 +2543,7 @@ static void idetape_pad_zeros (ide_drive_t *drive, int bcount)
idetape_tape_t *tape = drive->driver_data; idetape_tape_t *tape = drive->driver_data;
struct idetape_bh *bh; struct idetape_bh *bh;
int blocks; int blocks;
while (bcount) { while (bcount) {
unsigned int count; unsigned int count;
...@@ -2691,10 +2583,9 @@ static int idetape_pipeline_size (ide_drive_t *drive) ...@@ -2691,10 +2583,9 @@ static int idetape_pipeline_size (ide_drive_t *drive)
} }
/* /*
* Rewinds the tape to the Beginning Of the current Partition (BOP). * Rewinds the tape to the Beginning Of the current Partition (BOP). We
* * currently support only one partition.
* We currently support only one partition. */
*/
static int idetape_rewind_tape (ide_drive_t *drive) static int idetape_rewind_tape (ide_drive_t *drive)
{ {
int retval; int retval;
...@@ -2716,13 +2607,7 @@ static int idetape_rewind_tape (ide_drive_t *drive) ...@@ -2716,13 +2607,7 @@ static int idetape_rewind_tape (ide_drive_t *drive)
return 0; return 0;
} }
/* /* mtio.h compatible commands should be issued to the chrdev interface. */
* Our special ide-tape ioctl's.
*
* Currently there aren't any ioctl's.
* mtio.h compatible commands should be issued to the character device
* interface.
*/
static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg) static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned long arg)
{ {
idetape_tape_t *tape = drive->driver_data; 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 ...@@ -2756,13 +2641,11 @@ static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd, unsigned l
} }
/* /*
* idetape_space_over_filemarks is now a bit more complicated than just * The function below is now a bit more complicated than just passing the
* passing the command to the tape since we may have crossed some * command to the tape since we may have crossed some filemarks during our
* filemarks during our pipelined read-ahead mode. * pipelined read-ahead mode. As a minor side effect, the pipeline enables us to
* * support MTFSFM when the filemark is in our internal pipeline even if the tape
* As a minor side effect, the pipeline enables us to support MTFSFM when * doesn't support spacing over filemarks in the reverse direction.
* the filemark is in our internal pipeline even if the tape doesn't
* support spacing over filemarks in the reverse direction.
*/ */
static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count) static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_count)
{ {
...@@ -2781,10 +2664,7 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c ...@@ -2781,10 +2664,7 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
} }
if (tape->chrdev_dir == IDETAPE_DIR_READ) { if (tape->chrdev_dir == IDETAPE_DIR_READ) {
/* /* its a read-ahead buffer, scan it for crossed filemarks. */
* We have a read-ahead buffer. Scan it for crossed
* filemarks.
*/
tape->merge_stage_size = 0; tape->merge_stage_size = 0;
if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags)) if (test_and_clear_bit(IDETAPE_FILEMARK, &tape->flags))
++count; ++count;
...@@ -2797,13 +2677,15 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c ...@@ -2797,13 +2677,15 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
spin_lock_irqsave(&tape->lock, flags); spin_lock_irqsave(&tape->lock, flags);
if (tape->first_stage == tape->active_stage) { if (tape->first_stage == tape->active_stage) {
/* /*
* We have reached the active stage in the read pipeline. * We have reached the active stage in the read
* There is no point in allowing the drive to continue * pipeline. There is no point in allowing the
* reading any farther, so we stop the pipeline. * drive to continue reading any farther, so we
* stop the pipeline.
* *
* This section should be moved to a separate subroutine, * This section should be moved to a separate
* because a similar function is performed in * subroutine because similar operations are
* __idetape_discard_read_pipeline(), for example. * done in __idetape_discard_read_pipeline(),
* for example.
*/ */
tape->next_stage = NULL; tape->next_stage = NULL;
spin_unlock_irqrestore(&tape->lock, flags); 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 ...@@ -2819,8 +2701,8 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
} }
/* /*
* The filemark was not found in our internal pipeline. * The filemark was not found in our internal pipeline; now we can issue
* Now we can issue the space command. * the space command.
*/ */
switch (mt_op) { switch (mt_op) {
case MTFSF: case MTFSF:
...@@ -2843,21 +2725,19 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c ...@@ -2843,21 +2725,19 @@ static int idetape_space_over_filemarks (ide_drive_t *drive,short mt_op,int mt_c
/* /*
* Our character device read / write functions. * Our character device read / write functions.
* *
* The tape is optimized to maximize throughput when it is transferring * The tape is optimized to maximize throughput when it is transferring an
* an integral number of the "continuous transfer limit", which is * integral number of the "continuous transfer limit", which is a parameter of
* a parameter of the specific tape (26 KB on my particular tape). * the specific tape (26kB on my particular tape, 32kB for Onstream).
* (32 kB for Onstream)
* *
* As of version 1.3 of the driver, the character device provides an * As of version 1.3 of the driver, the character device provides an abstract
* abstract continuous view of the media - any mix of block sizes (even 1 * continuous view of the media - any mix of block sizes (even 1 byte) on the
* byte) on the same backup/restore procedure is supported. The driver * same backup/restore procedure is supported. The driver will internally
* will internally convert the requests to the recommended transfer unit, * convert the requests to the recommended transfer unit, so that an unmatch
* so that an unmatch between the user's block size to the recommended * between the user's block size to the recommended size will only result in a
* size will only result in a (slightly) increased driver overhead, but * (slightly) increased driver overhead, but will no longer hit performance.
* will no longer hit performance. * This is not applicable to Onstream.
* This is not applicable to Onstream.
*/ */
static ssize_t idetape_chrdev_read (struct file *file, char __user *buf, static ssize_t idetape_chrdev_read (struct file *file, char __user *buf,
size_t count, loff_t *ppos) size_t count, loff_t *ppos)
...@@ -2950,11 +2830,10 @@ static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf, ...@@ -2950,11 +2830,10 @@ static ssize_t idetape_chrdev_write (struct file *file, const char __user *buf,
idetape_init_merge_stage(tape); idetape_init_merge_stage(tape);
/* /*
* Issue a write 0 command to ensure that DSC handshake * Issue a write 0 command to ensure that DSC handshake is
* is switched from completion mode to buffer available * switched from completion mode to buffer available mode. No
* mode. * point in issuing this if DSC overlap isn't supported, some
* No point in issuing this if DSC overlap isn't supported, * drives (Seagate STT3401A) will return an error.
* some drives (Seagate STT3401A) will return an error.
*/ */
if (drive->dsc_overlap) { if (drive->dsc_overlap) {
ssize_t retval = idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, 0, tape->merge_stage->bh); 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) ...@@ -3045,9 +2924,7 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n", debug_log(DBG_ERR, "Handling MTIOCTOP ioctl: mt_op=%d, mt_count=%d\n",
mt_op, mt_count); mt_op, mt_count);
/* /* Commands which need our pipelined read-ahead stages. */
* Commands which need our pipelined read-ahead stages.
*/
switch (mt_op) { switch (mt_op) {
case MTFSF: case MTFSF:
case MTFSFM: case MTFSFM:
...@@ -3235,9 +3112,6 @@ static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive) ...@@ -3235,9 +3112,6 @@ static void ide_tape_get_bsize_from_bdesc(ide_drive_t *drive)
tape->drv_write_prot = (pc.buffer[2] & 0x80) >> 7; tape->drv_write_prot = (pc.buffer[2] & 0x80) >> 7;
} }
/*
* Our character device open function.
*/
static int idetape_chrdev_open (struct inode *inode, struct file *filp) static int idetape_chrdev_open (struct inode *inode, struct file *filp)
{ {
unsigned int minor = iminor(inode), i = minor & ~0xc0; unsigned int minor = iminor(inode), i = minor & ~0xc0;
...@@ -3304,9 +3178,7 @@ static int idetape_chrdev_open (struct inode *inode, struct file *filp) ...@@ -3304,9 +3178,7 @@ static int idetape_chrdev_open (struct inode *inode, struct file *filp)
} }
} }
/* /* Lock the tape drive door so user can't eject. */
* Lock the tape drive door so user can't eject.
*/
if (tape->chrdev_dir == IDETAPE_DIR_NONE) { if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
if (idetape_create_prevent_cmd(drive, &pc, 1)) { if (idetape_create_prevent_cmd(drive, &pc, 1)) {
if (!idetape_queue_pc_tail(drive, &pc)) { if (!idetape_queue_pc_tail(drive, &pc)) {
...@@ -3341,9 +3213,6 @@ static void idetape_write_release (ide_drive_t *drive, unsigned int minor) ...@@ -3341,9 +3213,6 @@ static void idetape_write_release (ide_drive_t *drive, unsigned int minor)
idetape_flush_tape_buffers(drive); idetape_flush_tape_buffers(drive);
} }
/*
* Our character device release function.
*/
static int idetape_chrdev_release (struct inode *inode, struct file *filp) static int idetape_chrdev_release (struct inode *inode, struct file *filp)
{ {
struct ide_tape_obj *tape = ide_tape_f(filp); struct ide_tape_obj *tape = ide_tape_f(filp);
...@@ -3500,9 +3369,6 @@ static void idetape_add_settings (ide_drive_t *drive) ...@@ -3500,9 +3369,6 @@ static void idetape_add_settings (ide_drive_t *drive)
{ {
idetape_tape_t *tape = drive->driver_data; idetape_tape_t *tape = drive->driver_data;
/*
* drive setting name read/write data type min max mul_factor div_factor data pointer set function
*/
ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff, ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
1, 2, (u16 *)&tape->caps[16], NULL); 1, 2, (u16 *)&tape->caps[16], NULL);
ide_add_setting(drive, "pipeline_min", SETTING_RW, TYPE_INT, 1, 0xffff, tape->stage_size / 1024, 1, &tape->min_pipeline, NULL); 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) { ; } ...@@ -3529,16 +3395,15 @@ static inline void idetape_add_settings(ide_drive_t *drive) { ; }
#endif #endif
/* /*
* ide_setup is called to: * The function below is called to:
* *
* 1. Initialize our various state variables. * 1. Initialize our various state variables.
* 2. Ask the tape for its capabilities. * 2. Ask the tape for its capabilities.
* 3. Allocate a buffer which will be used for data * 3. Allocate a buffer which will be used for data transfer. The buffer size
* transfer. The buffer size is chosen based on * is chosen based on the recommendation which we received in step 2.
* the recommendation which we received in step (2).
* *
* Note that at this point ide.c already assigned us an irq, so that * Note that at this point ide.c already assigned us an irq, so that we can
* we can queue requests here and wait for their completion. * queue requests here and wait for their completion.
*/ */
static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor) static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
{ {
...@@ -3572,7 +3437,7 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor) ...@@ -3572,7 +3437,7 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags); set_bit(IDETAPE_DRQ_INTERRUPT, &tape->flags);
tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10; tape->min_pipeline = tape->max_pipeline = tape->max_stages = 10;
idetape_get_inquiry_results(drive); idetape_get_inquiry_results(drive);
idetape_get_mode_sense_results(drive); idetape_get_mode_sense_results(drive);
ide_tape_get_bsize_from_bdesc(drive); 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) ...@@ -3595,9 +3460,7 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
tape->max_stages = speed * 1000 * 10 / tape->stage_size; tape->max_stages = speed * 1000 * 10 / tape->stage_size;
/* /* Limit memory use for pipeline to 10% of physical memory */
* Limit memory use for pipeline to 10% of physical memory
*/
si_meminfo(&si); si_meminfo(&si);
if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10) if (tape->max_stages * tape->stage_size > si.totalram * si.mem_unit / 10)
tape->max_stages = si.totalram * si.mem_unit / (10 * tape->stage_size); 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) ...@@ -3617,8 +3480,8 @@ static void idetape_setup (ide_drive_t *drive, idetape_tape_t *tape, int minor)
t = t1; t = t1;
/* /*
* Ensure that the number we got makes sense; limit * Ensure that the number we got makes sense; limit it within
* it within IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX. * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
*/ */
tape->best_dsc_rw_freq = max_t(unsigned long, tape->best_dsc_rw_freq = max_t(unsigned long,
min_t(unsigned long, t, IDETAPE_DSC_RW_MAX), min_t(unsigned long, t, IDETAPE_DSC_RW_MAX),
...@@ -3706,9 +3569,7 @@ static ide_driver_t idetape_driver = { ...@@ -3706,9 +3569,7 @@ static ide_driver_t idetape_driver = {
#endif #endif
}; };
/* /* Our character device supporting functions, passed to register_chrdev. */
* Our character device supporting functions, passed to register_chrdev.
*/
static const struct file_operations idetape_fops = { static const struct file_operations idetape_fops = {
.owner = THIS_MODULE, .owner = THIS_MODULE,
.read = idetape_chrdev_read, .read = idetape_chrdev_read,
......
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