Commit ddfe7a77 authored by Borislav Petkov's avatar Borislav Petkov Committed by Bartlomiej Zolnierkiewicz
Browse files

ide-tape remove pipeline speed/control calculations 



Pipeline handling calculations in idetape_calculate_speeds() can
go since they do not have any effect on other functionality besides:

1. info is only being exported through /proc as a read-only item
(controlled_pipeline_head_speed, uncontrolled_pipeline_head_speed)

2. used in idetape_restart_speed_control() which, in turn, is unrelated to
other code

3. used only for pipeline frames number accounting (tape->pipeline_head),
also unused elsewhere.

4.some variables are:
        only written to: tape->buffer_head;
        unused: tape->tape_head, tape->last_tape_head

Signed-off-by: default avatarBorislav Petkov <petkovbb@gmail.com>
Signed-off-by: default avatarBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
parent 97c566ce

drivers/ide/ide-tape.c

+0 −131
Original line number Diff line number Diff line
@@ -84,9 +84,6 @@ enum { 
 * We start from MIN maximum stages (we will not even use MIN stages if we don't

 * need them), increment it by RATE*(MAX-MIN) whenever we sense that the

 * pipeline is empty, until we reach the optimum value or until we reach MAX.

 *

 * Setting the following parameter to 0 is illegal: the pipelined mode cannot be

 * disabled (idetape_calculate_speeds() divides by tape->max_stages.)

 */

#define IDETAPE_MIN_PIPELINE_STAGES	  1

#define IDETAPE_MAX_PIPELINE_STAGES	400
@@ -392,39 +389,12 @@ typedef struct ide_tape_obj { 
	 */

	int postpone_cnt;



	/*

	 * Measures number of frames:

	 *

	 * 1. written/read to/from the driver pipeline (pipeline_head).

	 * 2. written/read to/from the tape buffers (idetape_bh).

	 * 3. written/read by the tape to/from the media (tape_head).

	 */

	int pipeline_head;

	int buffer_head;

	int tape_head;

	int last_tape_head;



	/* Speed control at the tape buffers input/output */

	unsigned long insert_time;

	int insert_size;

	int insert_speed;

	int max_insert_speed;

	int measure_insert_time;



	/* Speed regulation negative feedback loop */

	int speed_control;

	int pipeline_head_speed;

	int controlled_pipeline_head_speed;

	int uncontrolled_pipeline_head_speed;

	int controlled_last_pipeline_head;

	unsigned long uncontrolled_pipeline_head_time;

	unsigned long controlled_pipeline_head_time;

	int controlled_previous_pipeline_head;

	int uncontrolled_previous_pipeline_head;

	unsigned long controlled_previous_head_time;

	unsigned long uncontrolled_previous_head_time;

	int restart_speed_control_req;



	u32 debug_mask;

} idetape_tape_t;
@@ -1333,69 +1303,6 @@ static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code) 
	pc->idetape_callback = &idetape_pc_callback;

}



static void idetape_calculate_speeds(ide_drive_t *drive)

{

	idetape_tape_t *tape = drive->driver_data;



	if (time_after(jiffies,

			tape->controlled_pipeline_head_time + 120 * HZ)) {

		tape->controlled_previous_pipeline_head =

			tape->controlled_last_pipeline_head;

		tape->controlled_previous_head_time =

			tape->controlled_pipeline_head_time;

		tape->controlled_last_pipeline_head = tape->pipeline_head;

		tape->controlled_pipeline_head_time = jiffies;

	}

	if (time_after(jiffies, tape->controlled_pipeline_head_time + 60 * HZ))

		tape->controlled_pipeline_head_speed = (tape->pipeline_head -

				tape->controlled_last_pipeline_head) * 32 * HZ /

				(jiffies - tape->controlled_pipeline_head_time);

	else if (time_after(jiffies, tape->controlled_previous_head_time))

		tape->controlled_pipeline_head_speed = (tape->pipeline_head -

				tape->controlled_previous_pipeline_head) * 32 *

			HZ / (jiffies - tape->controlled_previous_head_time);



	if (tape->nr_pending_stages < tape->max_stages/*- 1 */) {

		/* -1 for read mode error recovery */

		if (time_after(jiffies, tape->uncontrolled_previous_head_time +

					10 * HZ)) {

			tape->uncontrolled_pipeline_head_time = jiffies;

			tape->uncontrolled_pipeline_head_speed =

				(tape->pipeline_head -

				 tape->uncontrolled_previous_pipeline_head) *

				32 * HZ / (jiffies -

					tape->uncontrolled_previous_head_time);

		}

	} else {

		tape->uncontrolled_previous_head_time = jiffies;

		tape->uncontrolled_previous_pipeline_head = tape->pipeline_head;

		if (time_after(jiffies, tape->uncontrolled_pipeline_head_time +

					30 * HZ))

			tape->uncontrolled_pipeline_head_time = jiffies;



	}

	tape->pipeline_head_speed = max(tape->uncontrolled_pipeline_head_speed,

					tape->controlled_pipeline_head_speed);



	if (tape->speed_control == 1) {

		if (tape->nr_pending_stages >= tape->max_stages / 2)

			tape->max_insert_speed = tape->pipeline_head_speed +

				(1100 - tape->pipeline_head_speed) * 2 *

				(tape->nr_pending_stages - tape->max_stages / 2)

				/ tape->max_stages;

		else

			tape->max_insert_speed = 500 +

				(tape->pipeline_head_speed - 500) * 2 *

				tape->nr_pending_stages / tape->max_stages;



		if (tape->nr_pending_stages >= tape->max_stages * 99 / 100)

			tape->max_insert_speed = 5000;

	} else

		tape->max_insert_speed = tape->speed_control;



	tape->max_insert_speed = max(tape->max_insert_speed, 500);

}



static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)

{

	idetape_tape_t *tape = drive->driver_data;
@@ -1548,7 +1455,6 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive, 
	if (time_after(jiffies, tape->insert_time))

		tape->insert_speed = tape->insert_size / 1024 * HZ /

					(jiffies - tape->insert_time);

	idetape_calculate_speeds(drive);

	if (!test_and_clear_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags) &&

	    (stat & SEEK_STAT) == 0) {

		if (postponed_rq == NULL) {
@@ -1572,7 +1478,6 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive, 
		return ide_stopped;

	}

	if (rq->cmd[0] & REQ_IDETAPE_READ) {

		tape->buffer_head++;

		tape->postpone_cnt = 0;

		pc = idetape_next_pc_storage(drive);

		idetape_create_read_cmd(tape, pc, rq->current_nr_sectors,
@@ -1580,7 +1485,6 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive, 
		goto out;

	}

	if (rq->cmd[0] & REQ_IDETAPE_WRITE) {

		tape->buffer_head++;

		tape->postpone_cnt = 0;

		pc = idetape_next_pc_storage(drive);

		idetape_create_write_cmd(tape, pc, rq->current_nr_sectors,
@@ -2321,24 +2225,6 @@ static void idetape_empty_write_pipeline(ide_drive_t *drive) 
	}

}



static void idetape_restart_speed_control(ide_drive_t *drive)

{

	idetape_tape_t *tape = drive->driver_data;



	tape->restart_speed_control_req = 0;

	tape->pipeline_head = 0;

	tape->controlled_last_pipeline_head = 0;

	tape->controlled_previous_pipeline_head = 0;

	tape->uncontrolled_previous_pipeline_head = 0;

	tape->controlled_pipeline_head_speed = 5000;

	tape->pipeline_head_speed = 5000;

	tape->uncontrolled_pipeline_head_speed = 0;

	tape->controlled_pipeline_head_time =

		tape->uncontrolled_pipeline_head_time = jiffies;

	tape->controlled_previous_head_time =

		tape->uncontrolled_previous_head_time = jiffies;

}



static int idetape_init_read(ide_drive_t *drive, int max_stages)

{

	idetape_tape_t *tape = drive->driver_data;
@@ -2381,8 +2267,6 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages) 
			}

		}

	}

	if (tape->restart_speed_control_req)

		idetape_restart_speed_control(drive);

	idetape_init_rq(&rq, REQ_IDETAPE_READ);

	rq.sector = tape->first_frame;

	rq.nr_sectors = blocks;
@@ -2451,8 +2335,6 @@ static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks) 
		spin_lock_irqsave(&tape->lock, flags);

		idetape_remove_stage_head(drive);

		spin_unlock_irqrestore(&tape->lock, flags);

		tape->pipeline_head++;

		idetape_calculate_speeds(drive);

	}

	if (bytes_read > blocks * tape->blk_size) {

		printk(KERN_ERR "ide-tape: bug: trying to return more bytes"
@@ -2787,8 +2669,6 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf, 
	}

	if (count == 0)

		return (0);

	if (tape->restart_speed_control_req)

		idetape_restart_speed_control(drive);

	if (tape->merge_stage_size) {

		if (tape->merge_stage_size >= tape->stage_size) {

			printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
@@ -2997,7 +2877,6 @@ static int idetape_chrdev_ioctl(struct inode *inode, struct file *file, 


	debug_log(DBG_CHRDEV, "Enter %s, cmd=%u\n", __func__, cmd);



	tape->restart_speed_control_req = 1;

	if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {

		idetape_empty_write_pipeline(drive);

		idetape_flush_tape_buffers(drive);
@@ -3140,8 +3019,6 @@ static int idetape_chrdev_open(struct inode *inode, struct file *filp) 
			}

		}

	}

	idetape_restart_speed_control(drive);

	tape->restart_speed_control_req = 0;

	return 0;



out_put_tape:
@@ -3344,12 +3221,6 @@ static void idetape_add_settings(ide_drive_t *drive) 
			NULL);

	ide_add_setting(drive, "dsc_overlap", SETTING_RW, TYPE_BYTE, 0, 1, 1,

			1, &drive->dsc_overlap, NULL);

	ide_add_setting(drive, "pipeline_head_speed_c", SETTING_READ, TYPE_INT,

			0, 0xffff, 1, 1, &tape->controlled_pipeline_head_speed,

			NULL);

	ide_add_setting(drive, "pipeline_head_speed_u", SETTING_READ, TYPE_INT,

			0, 0xffff, 1, 1,

			&tape->uncontrolled_pipeline_head_speed, NULL);

	ide_add_setting(drive, "avg_speed", SETTING_READ, TYPE_INT, 0, 0xffff,

			1, 1, &tape->avg_speed, NULL);

	ide_add_setting(drive, "debug_mask", SETTING_RW, TYPE_INT, 0, 0xffff, 1,
@@ -3395,8 +3266,6 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor) 
	tape->name[2] = '0' + minor;

	tape->chrdev_dir = IDETAPE_DIR_NONE;

	tape->pc = tape->pc_stack;

	tape->max_insert_speed = 10000;

	tape->speed_control = 1;

	*((unsigned short *) &gcw) = drive->id->config;



	/* Command packet DRQ type */

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