Merge branch 'master' of /pub/scm/linux/kernel/git/torvalds/linux-2.6

1 files changed, 210 insertions, 994 deletions

diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index f43fd070f1b6..29870c415110 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -72,26 +72,6 @@ enum {
 #endif
 
 /**************************** Tunable parameters *****************************/
-
-
-/*
- * Pipelined mode parameters.
- *
- * We try to use the minimum number of stages which is enough to keep the tape
- * constantly streaming. To accomplish that, we implement a feedback loop around
- * the maximum number of stages:
- *
- * 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
-#define IDETAPE_INCREASE_STAGES_RATE	 20
-
 /*
  * After each failed packet command we issue a request sense command and retry
  * the packet command IDETAPE_MAX_PC_RETRIES times.
@@ -224,28 +204,17 @@ enum {
 	/* 0 When the tape position is unknown */
 	IDETAPE_FLAG_ADDRESS_VALID	= (1 <<	1),
 	/* Device already opened */
-	IDETAPE_FLAG_BUSY			= (1 << 2),
-	/* Error detected in a pipeline stage */
-	IDETAPE_FLAG_PIPELINE_ERR	= (1 <<	3),
+	IDETAPE_FLAG_BUSY		= (1 << 2),
 	/* Attempt to auto-detect the current user block size */
-	IDETAPE_FLAG_DETECT_BS		= (1 << 4),
+	IDETAPE_FLAG_DETECT_BS		= (1 << 3),
 	/* Currently on a filemark */
-	IDETAPE_FLAG_FILEMARK		= (1 << 5),
+	IDETAPE_FLAG_FILEMARK		= (1 << 4),
 	/* DRQ interrupt device */
-	IDETAPE_FLAG_DRQ_INTERRUPT	= (1 << 6),
-	/* pipeline active */
-	IDETAPE_FLAG_PIPELINE_ACTIVE	= (1 << 7),
+	IDETAPE_FLAG_DRQ_INTERRUPT	= (1 << 5),
 	/* 0 = no tape is loaded, so we don't rewind after ejecting */
-	IDETAPE_FLAG_MEDIUM_PRESENT	= (1 << 8),
+	IDETAPE_FLAG_MEDIUM_PRESENT	= (1 << 6),
 };
 
-/* A pipeline stage. */
-typedef struct idetape_stage_s {
-	struct request rq;			/* The corresponding request */
-	struct idetape_bh *bh;			/* The data buffers */
-	struct idetape_stage_s *next;		/* Pointer to the next stage */
-} idetape_stage_t;
-
 /*
  * Most of our global data which we need to save even as we leave the driver due
  * to an interrupt or a timer event is stored in the struct defined below.
@@ -289,9 +258,7 @@ typedef struct ide_tape_obj {
 	 * While polling for DSC we use postponed_rq to postpone the current
 	 * request so that ide.c will be able to service pending requests on the
 	 * other device. Note that at most we will have only one DSC (usually
-	 * data transfer) request in the device request queue. Additional
-	 * requests can be queued in our internal pipeline, but they will be
-	 * visible to ide.c only one at a time.
+	 * data transfer) request in the device request queue.
 	 */
 	struct request *postponed_rq;
 	/* The time in which we started polling for DSC */
@@ -331,43 +298,20 @@ typedef struct ide_tape_obj {
 	 * 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 recommendation.
 	 */
-	/* ptr to the request which is waiting in the device request queue */
-	struct request *active_data_rq;
+
 	/* Data buffer size chosen based on the tape's recommendation */
-	int stage_size;
-	idetape_stage_t *merge_stage;
-	int merge_stage_size;
+	int buffer_size;
+	/* merge buffer */
+	struct idetape_bh *merge_bh;
+	/* size of the merge buffer */
+	int merge_bh_size;
+	/* pointer to current buffer head within the merge buffer */
 	struct idetape_bh *bh;
 	char *b_data;
 	int b_count;
 
-	/*
-	 * Pipeline parameters.
-	 *
-	 * To accomplish non-pipelined mode, we simply set the following
-	 * variables to zero (or NULL, where appropriate).
-	 */
-	/* Number of currently used stages */
-	int nr_stages;
-	/* Number of pending stages */
-	int nr_pending_stages;
-	/* We will not allocate more than this number of stages */
-	int max_stages, min_pipeline, max_pipeline;
-	/* The first stage which will be removed from the pipeline */
-	idetape_stage_t *first_stage;
-	/* The currently active stage */
-	idetape_stage_t *active_stage;
-	/* Will be serviced after the currently active request */
-	idetape_stage_t *next_stage;
-	/* New requests will be added to the pipeline here */
-	idetape_stage_t *last_stage;
-	/* Optional free stage which we can use */
-	idetape_stage_t *cache_stage;
-	int pages_per_stage;
+	int pages_per_buffer;
 	/* Wasted space in each stage */
 	int excess_bh_size;
 
@@ -388,45 +332,6 @@ typedef struct ide_tape_obj {
 	/* the tape is write protected (hardware or opened as read-only) */
 	char write_prot;
 
-	/*
-	 * Limit the number of times a request can be postponed, to avoid an
-	 * infinite postpone deadlock.
-	 */
-	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;
 
@@ -674,128 +579,36 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 	}
 }
 
-static void idetape_activate_next_stage(ide_drive_t *drive)
+/* Free data buffers completely. */
+static void ide_tape_kfree_buffer(idetape_tape_t *tape)
 {
-	idetape_tape_t *tape = drive->driver_data;
-	idetape_stage_t *stage = tape->next_stage;
-	struct request *rq = &stage->rq;
+	struct idetape_bh *prev_bh, *bh = tape->merge_bh;
 
-	debug_log(DBG_PROCS, "Enter %s\n", __func__);
+	while (bh) {
+		u32 size = bh->b_size;
 
-	if (stage == NULL) {
-		printk(KERN_ERR "ide-tape: bug: Trying to activate a non"
-				" existing stage\n");
-		return;
-	}
+		while (size) {
+			unsigned int order = fls(size >> PAGE_SHIFT)-1;
 
-	rq->rq_disk = tape->disk;
-	rq->buffer = NULL;
-	rq->special = (void *)stage->bh;
-	tape->active_data_rq = rq;
-	tape->active_stage = stage;
-	tape->next_stage = stage->next;
-}
-
-/* Free a stage along with its related buffers completely. */
-static void __idetape_kfree_stage(idetape_stage_t *stage)
-{
-	struct idetape_bh *prev_bh, *bh = stage->bh;
-	int size;
-
-	while (bh != NULL) {
-		if (bh->b_data != NULL) {
-			size = (int) bh->b_size;
-			while (size > 0) {
-				free_page((unsigned long) bh->b_data);
-				size -= PAGE_SIZE;
-				bh->b_data += PAGE_SIZE;
-			}
+			if (bh->b_data)
+				free_pages((unsigned long)bh->b_data, order);
+
+			size &= (order-1);
+			bh->b_data += (1 << order) * PAGE_SIZE;
 		}
 		prev_bh = bh;
 		bh = bh->b_reqnext;
 		kfree(prev_bh);
 	}
-	kfree(stage);
-}
-
-static void idetape_kfree_stage(idetape_tape_t *tape, idetape_stage_t *stage)
-{
-	__idetape_kfree_stage(stage);
+	kfree(tape->merge_bh);
 }
 
-/*
- * Remove tape->first_stage from the pipeline. The caller should avoid race
- * conditions.
- */
-static void idetape_remove_stage_head(ide_drive_t *drive)
-{
-	idetape_tape_t *tape = drive->driver_data;
-	idetape_stage_t *stage;
-
-	debug_log(DBG_PROCS, "Enter %s\n", __func__);
-
-	if (tape->first_stage == NULL) {
-		printk(KERN_ERR "ide-tape: bug: tape->first_stage is NULL\n");
-		return;
-	}
-	if (tape->active_stage == tape->first_stage) {
-		printk(KERN_ERR "ide-tape: bug: Trying to free our active "
-				"pipeline stage\n");
-		return;
-	}
-	stage = tape->first_stage;
-	tape->first_stage = stage->next;
-	idetape_kfree_stage(tape, stage);
-	tape->nr_stages--;
-	if (tape->first_stage == NULL) {
-		tape->last_stage = NULL;
-		if (tape->next_stage != NULL)
-			printk(KERN_ERR "ide-tape: bug: tape->next_stage !="
-					" NULL\n");
-		if (tape->nr_stages)
-			printk(KERN_ERR "ide-tape: bug: nr_stages should be 0 "
-					"now\n");
-	}
-}
-
-/*
- * This will free all the pipeline stages starting from new_last_stage->next
- * to the end of the list, and point tape->last_stage to new_last_stage.
- */
-static void idetape_abort_pipeline(ide_drive_t *drive,
-				   idetape_stage_t *new_last_stage)
-{
-	idetape_tape_t *tape = drive->driver_data;
-	idetape_stage_t *stage = new_last_stage->next;
-	idetape_stage_t *nstage;
-
-	debug_log(DBG_PROCS, "%s: Enter %s\n", tape->name, __func__);
-
-	while (stage) {
-		nstage = stage->next;
-		idetape_kfree_stage(tape, stage);
-		--tape->nr_stages;
-		--tape->nr_pending_stages;
-		stage = nstage;
-	}
-	if (new_last_stage)
-		new_last_stage->next = NULL;
-	tape->last_stage = new_last_stage;
-	tape->next_stage = NULL;
-}
-
-/*
- * Finish servicing a request and insert a pending pipeline request into the
- * main device queue.
- */
 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
 {
 	struct request *rq = HWGROUP(drive)->rq;
 	idetape_tape_t *tape = drive->driver_data;
 	unsigned long flags;
 	int error;
-	int remove_stage = 0;
-	idetape_stage_t *active_stage;
 
 	debug_log(DBG_PROCS, "Enter %s\n", __func__);
 
@@ -815,58 +628,8 @@ static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
 
 	spin_lock_irqsave(&tape->lock, flags);
 
-	/* The request was a pipelined data transfer request */
-	if (tape->active_data_rq == rq) {
-		active_stage = tape->active_stage;
-		tape->active_stage = NULL;
-		tape->active_data_rq = NULL;
-		tape->nr_pending_stages--;
-		if (rq->cmd[0] & REQ_IDETAPE_WRITE) {
-			remove_stage = 1;
-			if (error) {
-				set_bit(IDETAPE_FLAG_PIPELINE_ERR,
-					&tape->flags);
-				if (error == IDETAPE_ERROR_EOD)
-					idetape_abort_pipeline(drive,
-								active_stage);
-			}
-		} else if (rq->cmd[0] & REQ_IDETAPE_READ) {
-			if (error == IDETAPE_ERROR_EOD) {
-				set_bit(IDETAPE_FLAG_PIPELINE_ERR,
-					&tape->flags);
-				idetape_abort_pipeline(drive, active_stage);
-			}
-		}
-		if (tape->next_stage != NULL) {
-			idetape_activate_next_stage(drive);
-
-			/* Insert the next request into the request queue. */
-			(void)ide_do_drive_cmd(drive, tape->active_data_rq,
-						ide_end);
-		} else if (!error) {
-			/*
-			 * This is a part of the feedback loop which tries to
-			 * find the optimum number of stages. We are starting
-			 * from a minimum maximum number of stages, and if we
-			 * sense that the pipeline is empty, we try to increase
-			 * it, until we reach the user compile time memory
-			 * limit.
-			 */
-			int i = (tape->max_pipeline - tape->min_pipeline) / 10;
-
-			tape->max_stages += max(i, 1);
-			tape->max_stages = max(tape->max_stages,
-						tape->min_pipeline);
-			tape->max_stages = min(tape->max_stages,
-						tape->max_pipeline);
-		}
-	}
 	ide_end_drive_cmd(drive, 0, 0);
 
-	if (remove_stage)
-		idetape_remove_stage_head(drive);
-	if (tape->active_data_rq == NULL)
-		clear_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags);
 	spin_unlock_irqrestore(&tape->lock, flags);
 	return 0;
 }
@@ -993,7 +756,7 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
 	stat = ide_read_status(drive);
 
 	if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
-		if (hwif->ide_dma_end(drive) || (stat & ERR_STAT)) {
+		if (hwif->dma_ops->dma_end(drive) || (stat & ERR_STAT)) {
 			/*
 			 * A DMA error is sometimes expected. For example,
 			 * if the tape is crossing a filemark during a
@@ -1083,10 +846,10 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
 		return ide_do_reset(drive);
 	}
 	/* Get the number of bytes to transfer on this interrupt. */
-	bcount = (hwif->INB(hwif->io_ports[IDE_BCOUNTH_OFFSET]) << 8) |
-		  hwif->INB(hwif->io_ports[IDE_BCOUNTL_OFFSET]);
+	bcount = (hwif->INB(hwif->io_ports.lbah_addr) << 8) |
+		  hwif->INB(hwif->io_ports.lbam_addr);
 
-	ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
+	ireason = hwif->INB(hwif->io_ports.nsect_addr);
 
 	if (ireason & CD) {
 		printk(KERN_ERR "ide-tape: CoD != 0 in %s\n", __func__);
@@ -1190,12 +953,12 @@ static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
 				"yet DRQ isn't asserted\n");
 		return startstop;
 	}
-	ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
+	ireason = hwif->INB(hwif->io_ports.nsect_addr);
 	while (retries-- && ((ireason & CD) == 0 || (ireason & IO))) {
 		printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while issuing "
 				"a packet command, retrying\n");
 		udelay(100);
-		ireason = hwif->INB(hwif->io_ports[IDE_IREASON_OFFSET]);
+		ireason = hwif->INB(hwif->io_ports.nsect_addr);
 		if (retries == 0) {
 			printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
 					"issuing a packet command, ignoring\n");
@@ -1213,7 +976,7 @@ static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
 #ifdef CONFIG_BLK_DEV_IDEDMA
 	/* Begin DMA, if necessary */
 	if (pc->flags & PC_FLAG_DMA_IN_PROGRESS)
-		hwif->dma_start(drive);
+		hwif->dma_ops->dma_start(drive);
 #endif
 	/* Send the actual packet */
 	HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
@@ -1279,7 +1042,7 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
 		ide_dma_off(drive);
 	}
 	if ((pc->flags & PC_FLAG_DMA_RECOMMENDED) && drive->using_dma)
-		dma_ok = !hwif->dma_setup(drive);
+		dma_ok = !hwif->dma_ops->dma_setup(drive);
 
 	ide_pktcmd_tf_load(drive, IDE_TFLAG_NO_SELECT_MASK |
 			   IDE_TFLAG_OUT_DEVICE, bcount, dma_ok);
@@ -1292,7 +1055,7 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
 				    IDETAPE_WAIT_CMD, NULL);
 		return ide_started;
 	} else {
-		hwif->OUTB(WIN_PACKETCMD, hwif->io_ports[IDE_COMMAND_OFFSET]);
+		hwif->OUTB(WIN_PACKETCMD, hwif->io_ports.command_addr);
 		return idetape_transfer_pc(drive);
 	}
 }
@@ -1335,69 +1098,6 @@ 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;
@@ -1432,17 +1132,7 @@ static ide_startstop_t idetape_rw_callback(ide_drive_t *drive)
 	int blocks = tape->pc->xferred / tape->blk_size;
 
 	tape->avg_size += blocks * tape->blk_size;
-	tape->insert_size += blocks * tape->blk_size;
-	if (tape->insert_size > 1024 * 1024)
-		tape->measure_insert_time = 1;
-	if (tape->measure_insert_time) {
-		tape->measure_insert_time = 0;
-		tape->insert_time = jiffies;
-		tape->insert_size = 0;
-	}
-	if (time_after(jiffies, tape->insert_time))
-		tape->insert_speed = tape->insert_size / 1024 * HZ /
-					(jiffies - tape->insert_time);
+
 	if (time_after_eq(jiffies, tape->avg_time + HZ)) {
 		tape->avg_speed = tape->avg_size * HZ /
 				(jiffies - tape->avg_time) / 1024;
@@ -1475,7 +1165,7 @@ static void idetape_create_read_cmd(idetape_tape_t *tape,
 	pc->buf = NULL;
 	pc->buf_size = length * tape->blk_size;
 	pc->req_xfer = pc->buf_size;
-	if (pc->req_xfer == tape->stage_size)
+	if (pc->req_xfer == tape->buffer_size)
 		pc->flags |= PC_FLAG_DMA_RECOMMENDED;
 }
 
@@ -1495,7 +1185,7 @@ static void idetape_create_write_cmd(idetape_tape_t *tape,
 	pc->buf = NULL;
 	pc->buf_size = length * tape->blk_size;
 	pc->req_xfer = pc->buf_size;
-	if (pc->req_xfer == tape->stage_size)
+	if (pc->req_xfer == tape->buffer_size)
 		pc->flags |= PC_FLAG_DMA_RECOMMENDED;
 }
 
@@ -1547,10 +1237,6 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
 		drive->post_reset = 0;
 	}
 
-	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) {
@@ -1574,16 +1260,12 @@ 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,
 					(struct idetape_bh *)rq->special);
 		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,
 					 (struct idetape_bh *)rq->special);
@@ -1604,111 +1286,91 @@ out:
 	return idetape_issue_pc(drive, pc);
 }
 
-/* Pipeline related functions */
-static inline int idetape_pipeline_active(idetape_tape_t *tape)
-{
-	int rc1, rc2;
-
-	rc1 = test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags);
-	rc2 = (tape->active_data_rq != NULL);
-	return rc1;
-}
-
 /*
- * The function below uses __get_free_page to allocate a pipeline stage, along
- * with all the necessary small buffers which together make a buffer of size
- * tape->stage_size (or a bit more). We attempt to combine sequential pages as
+ * The function below uses __get_free_pages to allocate a data buffer of size
+ * tape->buffer_size (or a bit more). We attempt to combine sequential pages as
  * much as possible.
  *
- * It returns a pointer to the new allocated stage, or NULL if we can't (or
- * don't want to) allocate a stage.
- *
- * Pipeline stages are optional and are used to increase performance. If we
- * can't allocate them, we'll manage without them.
+ * It returns a pointer to the newly allocated buffer, or NULL in case of
+ * failure.
  */
-static idetape_stage_t *__idetape_kmalloc_stage(idetape_tape_t *tape, int full,
-						int clear)
+static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
+						  int full, int clear)
 {
-	idetape_stage_t *stage;
-	struct idetape_bh *prev_bh, *bh;
-	int pages = tape->pages_per_stage;
+	struct idetape_bh *prev_bh, *bh, *merge_bh;
+	int pages = tape->pages_per_buffer;
+	unsigned int order, b_allocd;
 	char *b_data = NULL;
 
-	stage = kmalloc(sizeof(idetape_stage_t), GFP_KERNEL);
-	if (!stage)
-		return NULL;
-	stage->next = NULL;
-
-	stage->bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
-	bh = stage->bh;
+	merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
+	bh = merge_bh;
 	if (bh == NULL)
 		goto abort;
-	bh->b_reqnext = NULL;
-	bh->b_data = (char *) __get_free_page(GFP_KERNEL);
+
+	order = fls(pages) - 1;
+	bh->b_data = (char *) __get_free_pages(GFP_KERNEL, order);
 	if (!bh->b_data)
 		goto abort;
+	b_allocd = (1 << order) * PAGE_SIZE;
+	pages &= (order-1);
+
 	if (clear)
-		memset(bh->b_data, 0, PAGE_SIZE);
-	bh->b_size = PAGE_SIZE;
+		memset(bh->b_data, 0, b_allocd);
+	bh->b_reqnext = NULL;
+	bh->b_size = b_allocd;
 	atomic_set(&bh->b_count, full ? bh->b_size : 0);
 
-	while (--pages) {
-		b_data = (char *) __get_free_page(GFP_KERNEL);
+	while (pages) {
+		order = fls(pages) - 1;
+		b_data = (char *) __get_free_pages(GFP_KERNEL, order);
 		if (!b_data)
 			goto abort;
+		b_allocd = (1 << order) * PAGE_SIZE;
+
 		if (clear)
-			memset(b_data, 0, PAGE_SIZE);
-		if (bh->b_data == b_data + PAGE_SIZE) {
-			bh->b_size += PAGE_SIZE;
-			bh->b_data -= PAGE_SIZE;
+			memset(b_data, 0, b_allocd);
+
+		/* newly allocated page frames below buffer header or ...*/
+		if (bh->b_data == b_data + b_allocd) {
+			bh->b_size += b_allocd;
+			bh->b_data -= b_allocd;
 			if (full)
-				atomic_add(PAGE_SIZE, &bh->b_count);
+				atomic_add(b_allocd, &bh->b_count);
 			continue;
 		}
+		/* they are above the header */
 		if (b_data == bh->b_data + bh->b_size) {
-			bh->b_size += PAGE_SIZE;
+			bh->b_size += b_allocd;
 			if (full)
-				atomic_add(PAGE_SIZE, &bh->b_count);
+				atomic_add(b_allocd, &bh->b_count);
 			continue;
 		}
 		prev_bh = bh;
 		bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
 		if (!bh) {
-			free_page((unsigned long) b_data);
+			free_pages((unsigned long) b_data, order);
 			goto abort;
 		}
 		bh->b_reqnext = NULL;
 		bh->b_data = b_data;
-		bh->b_size = PAGE_SIZE;
+		bh->b_size = b_allocd;
 		atomic_set(&bh->b_count, full ? bh->b_size : 0);
 		prev_bh->b_reqnext = bh;
+
+		pages &= (order-1);
 	}
+
 	bh->b_size -= tape->excess_bh_size;
 	if (full)
 		atomic_sub(tape->excess_bh_size, &bh->b_count);
-	return stage;
+	return merge_bh;
 abort:
-	__idetape_kfree_stage(stage);
+	ide_tape_kfree_buffer(tape);
 	return NULL;
 }
 
-static idetape_stage_t *idetape_kmalloc_stage(idetape_tape_t *tape)
-{
-	idetape_stage_t *cache_stage = tape->cache_stage;
-
-	debug_log(DBG_PROCS, "Enter %s\n", __func__);
-
-	if (tape->nr_stages >= tape->max_stages)
-		return NULL;
-	if (cache_stage != NULL) {
-		tape->cache_stage = NULL;
-		return cache_stage;
-	}
-	return __idetape_kmalloc_stage(tape, 0, 0);
-}
-
 static int idetape_copy_stage_from_user(idetape_tape_t *tape,
-		idetape_stage_t *stage, const char __user *buf, int n)
+					const char __user *buf, int n)
 {
 	struct idetape_bh *bh = tape->bh;
 	int count;
@@ -1740,7 +1402,7 @@ static int idetape_copy_stage_from_user(idetape_tape_t *tape,
 }
 
 static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
-		idetape_stage_t *stage, int n)
+				      int n)
 {
 	struct idetape_bh *bh = tape->bh;
 	int count;
@@ -1771,11 +1433,11 @@ static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
 	return ret;
 }
 
-static void idetape_init_merge_stage(idetape_tape_t *tape)
+static void idetape_init_merge_buffer(idetape_tape_t *tape)
 {
-	struct idetape_bh *bh = tape->merge_stage->bh;
+	struct idetape_bh *bh = tape->merge_bh;
+	tape->bh = tape->merge_bh;
 
-	tape->bh = bh;
 	if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
 		atomic_set(&bh->b_count, 0);
 	else {
@@ -1784,61 +1446,6 @@ static void idetape_init_merge_stage(idetape_tape_t *tape)
 	}
 }
 
-static void idetape_switch_buffers(idetape_tape_t *tape, idetape_stage_t *stage)
-{
-	struct idetape_bh *tmp;
-
-	tmp = stage->bh;
-	stage->bh = tape->merge_stage->bh;
-	tape->merge_stage->bh = tmp;
-	idetape_init_merge_stage(tape);
-}
-
-/* Add a new stage at the end of the pipeline. */
-static void idetape_add_stage_tail(ide_drive_t *drive, idetape_stage_t *stage)
-{
-	idetape_tape_t *tape = drive->driver_data;
-	unsigned long flags;
-
-	debug_log(DBG_PROCS, "Enter %s\n", __func__);
-
-	spin_lock_irqsave(&tape->lock, flags);
-	stage->next = NULL;
-	if (tape->last_stage != NULL)
-		tape->last_stage->next = stage;
-	else
-		tape->first_stage = stage;
-		tape->next_stage  = stage;
-	tape->last_stage = stage;
-	if (tape->next_stage == NULL)
-		tape->next_stage = tape->last_stage;
-	tape->nr_stages++;
-	tape->nr_pending_stages++;
-	spin_unlock_irqrestore(&tape->lock, flags);
-}
-
-/* Install a completion in a pending request and sleep until it is serviced. 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)
-{
-	DECLARE_COMPLETION_ONSTACK(wait);
-	idetape_tape_t *tape = drive->driver_data;
-
-	if (rq == NULL || !blk_special_request(rq)) {
-		printk(KERN_ERR "ide-tape: bug: Trying to sleep on non-valid"
-				 " request\n");
-		return;
-	}
-	rq->end_io_data = &wait;
-	rq->end_io = blk_end_sync_rq;
-	spin_unlock_irq(&tape->lock);
-	wait_for_completion(&wait);
-	/* The stage and its struct request have been deallocated */
-	spin_lock_irq(&tape->lock);
-}
-
 static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
 {
 	idetape_tape_t *tape = drive->driver_data;
@@ -1907,7 +1514,7 @@ static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
  * 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, struct ide_atapi_pc *pc)
+static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
 {
 	struct ide_tape_obj *tape = drive->driver_data;
 	struct request rq;
@@ -1939,7 +1546,7 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
 	timeout += jiffies;
 	while (time_before(jiffies, timeout)) {
 		idetape_create_test_unit_ready_cmd(&pc);
-		if (!__idetape_queue_pc_tail(drive, &pc))
+		if (!idetape_queue_pc_tail(drive, &pc))
 			return 0;
 		if ((tape->sense_key == 2 && tape->asc == 4 && tape->ascq == 2)
 		    || (tape->asc == 0x3A)) {
@@ -1948,7 +1555,7 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
 				return -ENOMEDIUM;
 			idetape_create_load_unload_cmd(drive, &pc,
 							IDETAPE_LU_LOAD_MASK);
-			__idetape_queue_pc_tail(drive, &pc);
+			idetape_queue_pc_tail(drive, &pc);
 			load_attempted = 1;
 		/* not about to be ready */
 		} else if (!(tape->sense_key == 2 && tape->asc == 4 &&
@@ -1959,11 +1566,6 @@ static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
 	return -EIO;
 }
 
-static int idetape_queue_pc_tail(ide_drive_t *drive, struct ide_atapi_pc *pc)
-{
-	return __idetape_queue_pc_tail(drive, pc);
-}
-
 static int idetape_flush_tape_buffers(ide_drive_t *drive)
 {
 	struct ide_atapi_pc pc;
@@ -2029,50 +1631,21 @@ static int idetape_create_prevent_cmd(ide_drive_t *drive,
 	return 1;
 }
 
-static int __idetape_discard_read_pipeline(ide_drive_t *drive)
+static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
 {
 	idetape_tape_t *tape = drive->driver_data;
-	unsigned long flags;
-	int cnt;
 
 	if (tape->chrdev_dir != IDETAPE_DIR_READ)
-		return 0;
+		return;
 
-	/* Remove merge stage. */
-	cnt = tape->merge_stage_size / tape->blk_size;
-	if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
-		++cnt;		/* Filemarks count as 1 sector */
-	tape->merge_stage_size = 0;
-	if (tape->merge_stage != NULL) {
-		__idetape_kfree_stage(tape->merge_stage);
-		tape->merge_stage = NULL;
+	clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
+	tape->merge_bh_size = 0;
+	if (tape->merge_bh != NULL) {
+		ide_tape_kfree_buffer(tape);
+		tape->merge_bh = NULL;
 	}
 
-	/* Clear pipeline flags. */
-	clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
 	tape->chrdev_dir = IDETAPE_DIR_NONE;
-
-	/* Remove pipeline stages. */
-	if (tape->first_stage == NULL)
-		return 0;
-
-	spin_lock_irqsave(&tape->lock, flags);
-	tape->next_stage = NULL;
-	if (idetape_pipeline_active(tape))
-		idetape_wait_for_request(drive, tape->active_data_rq);
-	spin_unlock_irqrestore(&tape->lock, flags);
-
-	while (tape->first_stage != NULL) {
-		struct request *rq_ptr = &tape->first_stage->rq;
-
-		cnt += rq_ptr->nr_sectors - rq_ptr->current_nr_sectors;
-		if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
-			++cnt;
-		idetape_remove_stage_head(drive);
-	}
-	tape->nr_pending_stages = 0;
-	tape->max_stages = tape->min_pipeline;
-	return cnt;
 }
 
 /*
@@ -2089,7 +1662,7 @@ static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
 	struct ide_atapi_pc pc;
 
 	if (tape->chrdev_dir == IDETAPE_DIR_READ)
-		__idetape_discard_read_pipeline(drive);
+		__ide_tape_discard_merge_buffer(drive);
 	idetape_wait_ready(drive, 60 * 5 * HZ);
 	idetape_create_locate_cmd(drive, &pc, block, partition, skip);
 	retval = idetape_queue_pc_tail(drive, &pc);
@@ -2100,20 +1673,19 @@ static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
 	return (idetape_queue_pc_tail(drive, &pc));
 }
 
-static void idetape_discard_read_pipeline(ide_drive_t *drive,
+static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
 					  int restore_position)
 {
 	idetape_tape_t *tape = drive->driver_data;
-	int cnt;
 	int seek, position;
 
-	cnt = __idetape_discard_read_pipeline(drive);
+	__ide_tape_discard_merge_buffer(drive);
 	if (restore_position) {
 		position = idetape_read_position(drive);
-		seek = position > cnt ? position - cnt : 0;
+		seek = position > 0 ? position : 0;
 		if (idetape_position_tape(drive, seek, 0, 0)) {
 			printk(KERN_INFO "ide-tape: %s: position_tape failed in"
-					 " discard_pipeline()\n", tape->name);
+					 " %s\n", tape->name, __func__);
 			return;
 		}
 	}
@@ -2131,12 +1703,6 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
 
 	debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
 
-	if (idetape_pipeline_active(tape)) {
-		printk(KERN_ERR "ide-tape: bug: the pipeline is active in %s\n",
-				__func__);
-		return (0);
-	}
-
 	idetape_init_rq(&rq, cmd);
 	rq.rq_disk = tape->disk;
 	rq.special = (void *)bh;
@@ -2148,27 +1714,13 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
 	if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
 		return 0;
 
-	if (tape->merge_stage)
-		idetape_init_merge_stage(tape);
+	if (tape->merge_bh)
+		idetape_init_merge_buffer(tape);
 	if (rq.errors == IDETAPE_ERROR_GENERAL)
 		return -EIO;
 	return (tape->blk_size * (blocks-rq.current_nr_sectors));
 }
 
-/* start servicing the pipeline stages, starting from tape->next_stage. */
-static void idetape_plug_pipeline(ide_drive_t *drive)
-{
-	idetape_tape_t *tape = drive->driver_data;
-
-	if (tape->next_stage == NULL)
-		return;
-	if (!idetape_pipeline_active(tape)) {
-		set_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags);
-		idetape_activate_next_stage(drive);
-		(void) ide_do_drive_cmd(drive, tape->active_data_rq, ide_end);
-	}
-}
-
 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
 {
 	idetape_init_pc(pc);
@@ -2206,135 +1758,39 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
 	pc->idetape_callback = &idetape_pc_callback;
 }
 
-static void idetape_wait_first_stage(ide_drive_t *drive)
-{
-	idetape_tape_t *tape = drive->driver_data;
-	unsigned long flags;
-
-	if (tape->first_stage == NULL)
-		return;
-	spin_lock_irqsave(&tape->lock, flags);
-	if (tape->active_stage == tape->first_stage)
-		idetape_wait_for_request(drive, tape->active_data_rq);
-	spin_unlock_irqrestore(&tape->lock, flags);
-}
-
-/*
- * Try to add a character device originated write request to our pipeline. In
- * case we don't succeed, we revert to non-pipelined operation mode for this
- * request. In order to accomplish that, we
- *
- * 1. Try to allocate a new pipeline stage.
- * 2. If we can't, wait for more and more requests to be serviced and try again
- * each time.
- * 3. If we still can't allocate a stage, fallback to non-pipelined operation
- * mode for this request.
- */
+/* Queue up a character device originated write request. */
 static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
 {
 	idetape_tape_t *tape = drive->driver_data;
-	idetape_stage_t *new_stage;
-	unsigned long flags;
-	struct request *rq;
 
 	debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
 
-	/* Attempt to allocate a new stage. Beware possible race conditions. */
-	while ((new_stage = idetape_kmalloc_stage(tape)) == NULL) {
-		spin_lock_irqsave(&tape->lock, flags);
-		if (idetape_pipeline_active(tape)) {
-			idetape_wait_for_request(drive, tape->active_data_rq);
-			spin_unlock_irqrestore(&tape->lock, flags);
-		} else {
-			spin_unlock_irqrestore(&tape->lock, flags);
-			idetape_plug_pipeline(drive);
-			if (idetape_pipeline_active(tape))
-				continue;
-			/*
-			 * The machine is short on memory. Fallback to non-
-			 * pipelined operation mode for this request.
-			 */
-			return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
-						blocks, tape->merge_stage->bh);
-		}
-	}
-	rq = &new_stage->rq;
-	idetape_init_rq(rq, REQ_IDETAPE_WRITE);
-	/* Doesn't actually matter - We always assume sequential access */
-	rq->sector = tape->first_frame;
-	rq->current_nr_sectors = blocks;
-	rq->nr_sectors = blocks;
-
-	idetape_switch_buffers(tape, new_stage);
-	idetape_add_stage_tail(drive, new_stage);
-	tape->pipeline_head++;
-	idetape_calculate_speeds(drive);
-
-	/*
-	 * Estimate whether the tape has stopped writing by checking if our
-	 * write pipeline is currently empty. If we are not writing anymore,
-	 * wait for the pipeline to be almost completely full (90%) before
-	 * starting to service requests, so that we will be able to keep up with
-	 * the higher speeds of the tape.
-	 */
-	if (!idetape_pipeline_active(tape)) {
-		if (tape->nr_stages >= tape->max_stages * 9 / 10 ||
-			tape->nr_stages >= tape->max_stages -
-			tape->uncontrolled_pipeline_head_speed * 3 * 1024 /
-			tape->blk_size) {
-			tape->measure_insert_time = 1;
-			tape->insert_time = jiffies;
-			tape->insert_size = 0;
-			tape->insert_speed = 0;
-			idetape_plug_pipeline(drive);
-		}
-	}
-	if (test_and_clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags))
-		/* Return a deferred error */
-		return -EIO;
-	return blocks;
-}
-
-/*
- * Wait until all pending pipeline requests are serviced. Typically called on
- * device close.
- */
-static void idetape_wait_for_pipeline(ide_drive_t *drive)
-{
-	idetape_tape_t *tape = drive->driver_data;
-	unsigned long flags;
-
-	while (tape->next_stage || idetape_pipeline_active(tape)) {
-		idetape_plug_pipeline(drive);
-		spin_lock_irqsave(&tape->lock, flags);
-		if (idetape_pipeline_active(tape))
-			idetape_wait_for_request(drive, tape->active_data_rq);
-		spin_unlock_irqrestore(&tape->lock, flags);
-	}
+	return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
+				     blocks, tape->merge_bh);
 }
 
-static void idetape_empty_write_pipeline(ide_drive_t *drive)
+static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
 {
 	idetape_tape_t *tape = drive->driver_data;
 	int blocks, min;
 	struct idetape_bh *bh;
 
 	if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
-		printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline,"
+		printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
 				" but we are not writing.\n");
 		return;
 	}
-	if (tape->merge_stage_size > tape->stage_size) {
+	if (tape->merge_bh_size > tape->buffer_size) {
 		printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
-		tape->merge_stage_size = tape->stage_size;
+		tape->merge_bh_size = tape->buffer_size;
 	}
-	if (tape->merge_stage_size) {
-		blocks = tape->merge_stage_size / tape->blk_size;
-		if (tape->merge_stage_size % tape->blk_size) {
+	if (tape->merge_bh_size) {
+		blocks = tape->merge_bh_size / tape->blk_size;
+		if (tape->merge_bh_size % tape->blk_size) {
 			unsigned int i;
 
 			blocks++;
-			i = tape->blk_size - tape->merge_stage_size %
+			i = tape->blk_size - tape->merge_bh_size %
 				tape->blk_size;
 			bh = tape->bh->b_reqnext;
 			while (bh) {
@@ -2358,74 +1814,33 @@ static void idetape_empty_write_pipeline(ide_drive_t *drive)
 			}
 		}
 		(void) idetape_add_chrdev_write_request(drive, blocks);
-		tape->merge_stage_size = 0;
+		tape->merge_bh_size = 0;
 	}
-	idetape_wait_for_pipeline(drive);
-	if (tape->merge_stage != NULL) {
-		__idetape_kfree_stage(tape->merge_stage);
-		tape->merge_stage = NULL;
+	if (tape->merge_bh != NULL) {
+		ide_tape_kfree_buffer(tape);
+		tape->merge_bh = NULL;
 	}
-	clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
 	tape->chrdev_dir = IDETAPE_DIR_NONE;
-
-	/*
-	 * On the next backup, perform the feedback loop again. (I don't want to
-	 * keep sense information between backups, as some systems are
-	 * constantly on, and the system load can be totally different on the
-	 * next backup).
-	 */
-	tape->max_stages = tape->min_pipeline;
-	if (tape->first_stage != NULL ||
-	    tape->next_stage != NULL ||
-	    tape->last_stage != NULL ||
-	    tape->nr_stages != 0) {
-		printk(KERN_ERR "ide-tape: ide-tape pipeline bug, "
-			"first_stage %p, next_stage %p, "
-			"last_stage %p, nr_stages %d\n",
-			tape->first_stage, tape->next_stage,
-			tape->last_stage, tape->nr_stages);
-	}
 }
 
-static void idetape_restart_speed_control(ide_drive_t *drive)
+static int idetape_init_read(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;
-	idetape_stage_t *new_stage;
-	struct request rq;
 	int bytes_read;
-	u16 blocks = *(u16 *)&tape->caps[12];
 
 	/* Initialize read operation */
 	if (tape->chrdev_dir != IDETAPE_DIR_READ) {
 		if (tape->chrdev_dir == IDETAPE_DIR_WRITE) {
-			idetape_empty_write_pipeline(drive);
+			ide_tape_flush_merge_buffer(drive);
 			idetape_flush_tape_buffers(drive);
 		}
-		if (tape->merge_stage || tape->merge_stage_size) {
-			printk(KERN_ERR "ide-tape: merge_stage_size should be"
+		if (tape->merge_bh || tape->merge_bh_size) {
+			printk(KERN_ERR "ide-tape: merge_bh_size should be"
 					 " 0 now\n");
-			tape->merge_stage_size = 0;
+			tape->merge_bh_size = 0;
 		}
-		tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
-		if (!tape->merge_stage)
+		tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
+		if (!tape->merge_bh)
 			return -ENOMEM;
 		tape->chrdev_dir = IDETAPE_DIR_READ;
 
@@ -2438,54 +1853,23 @@ static int idetape_init_read(ide_drive_t *drive, int max_stages)
 		if (drive->dsc_overlap) {
 			bytes_read = idetape_queue_rw_tail(drive,
 							REQ_IDETAPE_READ, 0,
-							tape->merge_stage->bh);
+							tape->merge_bh);
 			if (bytes_read < 0) {
-				__idetape_kfree_stage(tape->merge_stage);
-				tape->merge_stage = NULL;
+				ide_tape_kfree_buffer(tape);
+				tape->merge_bh = NULL;
 				tape->chrdev_dir = IDETAPE_DIR_NONE;
 				return bytes_read;
 			}
 		}
 	}
-	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;
-	rq.current_nr_sectors = blocks;
-	if (!test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags) &&
-	    tape->nr_stages < max_stages) {
-		new_stage = idetape_kmalloc_stage(tape);
-		while (new_stage != NULL) {
-			new_stage->rq = rq;
-			idetape_add_stage_tail(drive, new_stage);
-			if (tape->nr_stages >= max_stages)
-				break;
-			new_stage = idetape_kmalloc_stage(tape);
-		}
-	}
-	if (!idetape_pipeline_active(tape)) {
-		if (tape->nr_pending_stages >= 3 * max_stages / 4) {
-			tape->measure_insert_time = 1;
-			tape->insert_time = jiffies;
-			tape->insert_size = 0;
-			tape->insert_speed = 0;
-			idetape_plug_pipeline(drive);
-		}
-	}
+
 	return 0;
 }
 
-/*
- * Called from idetape_chrdev_read() to service a character device read request
- * and add read-ahead requests to our pipeline.
- */
+/* called from idetape_chrdev_read() to service a chrdev read request. */
 static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
 {
 	idetape_tape_t *tape = drive->driver_data;
-	unsigned long flags;
-	struct request *rq_ptr;
-	int bytes_read;
 
 	debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
 
@@ -2493,39 +1877,10 @@ static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
 	if (test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
 		return 0;
 
-	/* Wait for the next block to reach the head of the pipeline. */
-	idetape_init_read(drive, tape->max_stages);
-	if (tape->first_stage == NULL) {
-		if (test_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags))
-			return 0;
-		return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
-					tape->merge_stage->bh);
-	}
-	idetape_wait_first_stage(drive);
-	rq_ptr = &tape->first_stage->rq;
-	bytes_read = tape->blk_size * (rq_ptr->nr_sectors -
-					rq_ptr->current_nr_sectors);
-	rq_ptr->nr_sectors = 0;
-	rq_ptr->current_nr_sectors = 0;
+	idetape_init_read(drive);
 
-	if (rq_ptr->errors == IDETAPE_ERROR_EOD)
-		return 0;
-	else {
-		idetape_switch_buffers(tape, tape->first_stage);
-		if (rq_ptr->errors == IDETAPE_ERROR_FILEMARK)
-			set_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
-		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"
-				" than requested\n");
-		bytes_read = blocks * tape->blk_size;
-	}
-	return (bytes_read);
+	return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
+				     tape->merge_bh);
 }
 
 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
@@ -2537,8 +1892,8 @@ static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
 	while (bcount) {
 		unsigned int count;
 
-		bh = tape->merge_stage->bh;
-		count = min(tape->stage_size, bcount);
+		bh = tape->merge_bh;
+		count = min(tape->buffer_size, bcount);
 		bcount -= count;
 		blocks = count / tape->blk_size;
 		while (count) {
@@ -2549,31 +1904,10 @@ static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
 			bh = bh->b_reqnext;
 		}
 		idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
-				      tape->merge_stage->bh);
+				      tape->merge_bh);
 	}
 }
 
-static int idetape_pipeline_size(ide_drive_t *drive)
-{
-	idetape_tape_t *tape = drive->driver_data;
-	idetape_stage_t *stage;
-	struct request *rq;
-	int size = 0;
-
-	idetape_wait_for_pipeline(drive);
-	stage = tape->first_stage;
-	while (stage != NULL) {
-		rq = &stage->rq;
-		size += tape->blk_size * (rq->nr_sectors -
-				rq->current_nr_sectors);
-		if (rq->errors == IDETAPE_ERROR_FILEMARK)
-			size += tape->blk_size;
-		stage = stage->next;
-	}
-	size += tape->merge_stage_size;
-	return size;
-}
-
 /*
  * Rewinds the tape to the Beginning Of the current Partition (BOP). We
  * currently support only one partition.
@@ -2619,11 +1953,10 @@ static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
 		if (copy_from_user(&config, argp, sizeof(config)))
 			return -EFAULT;
 		tape->best_dsc_rw_freq = config.dsc_rw_frequency;
-		tape->max_stages = config.nr_stages;
 		break;
 	case 0x0350:
 		config.dsc_rw_frequency = (int) tape->best_dsc_rw_freq;
-		config.nr_stages = tape->max_stages;
+		config.nr_stages = 1;
 		if (copy_to_user(argp, &config, sizeof(config)))
 			return -EFAULT;
 		break;
@@ -2633,19 +1966,11 @@ static int idetape_blkdev_ioctl(ide_drive_t *drive, unsigned int cmd,
 	return 0;
 }
 
-/*
- * The function below is now a bit more complicated than just passing the
- * command to the tape since we may have crossed some filemarks during our
- * 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
- * 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)
 {
 	idetape_tape_t *tape = drive->driver_data;
 	struct ide_atapi_pc pc;
-	unsigned long flags;
 	int retval, count = 0;
 	int sprev = !!(tape->caps[4] & 0x20);
 
@@ -2658,48 +1983,12 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
 	}
 
 	if (tape->chrdev_dir == IDETAPE_DIR_READ) {
-		/* its a read-ahead buffer, scan it for crossed filemarks. */
-		tape->merge_stage_size = 0;
+		tape->merge_bh_size = 0;
 		if (test_and_clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags))
 			++count;
-		while (tape->first_stage != NULL) {
-			if (count == mt_count) {
-				if (mt_op == MTFSFM)
-					set_bit(IDETAPE_FLAG_FILEMARK,
-						&tape->flags);
-				return 0;
-			}
-			spin_lock_irqsave(&tape->lock, flags);
-			if (tape->first_stage == tape->active_stage) {
-				/*
-				 * We have reached the active stage in the read
-				 * pipeline. There is no point in allowing the
-				 * drive to continue reading any farther, so we
-				 * stop the pipeline.
-				 *
-				 * This section should be moved to a separate
-				 * subroutine because similar operations are
-				 * done in __idetape_discard_read_pipeline(),
-				 * for example.
-				 */
-				tape->next_stage = NULL;
-				spin_unlock_irqrestore(&tape->lock, flags);
-				idetape_wait_first_stage(drive);
-				tape->next_stage = tape->first_stage->next;
-			} else
-				spin_unlock_irqrestore(&tape->lock, flags);
-			if (tape->first_stage->rq.errors ==
-					IDETAPE_ERROR_FILEMARK)
-				++count;
-			idetape_remove_stage_head(drive);
-		}
-		idetape_discard_read_pipeline(drive, 0);
+		ide_tape_discard_merge_buffer(drive, 0);
 	}
 
-	/*
-	 * The filemark was not found in our internal pipeline;	now we can issue
-	 * the space command.
-	 */
 	switch (mt_op) {
 	case MTFSF:
 	case MTBSF:
@@ -2755,27 +2044,25 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
 			    (count % tape->blk_size) == 0)
 				tape->user_bs_factor = count / tape->blk_size;
 	}
-	rc = idetape_init_read(drive, tape->max_stages);
+	rc = idetape_init_read(drive);
 	if (rc < 0)
 		return rc;
 	if (count == 0)
 		return (0);
-	if (tape->merge_stage_size) {
-		actually_read = min((unsigned int)(tape->merge_stage_size),
+	if (tape->merge_bh_size) {
+		actually_read = min((unsigned int)(tape->merge_bh_size),
 				    (unsigned int)count);
-		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
-					       actually_read))
+		if (idetape_copy_stage_to_user(tape, buf, actually_read))
 			ret = -EFAULT;
 		buf += actually_read;
-		tape->merge_stage_size -= actually_read;
+		tape->merge_bh_size -= actually_read;
 		count -= actually_read;
 	}
-	while (count >= tape->stage_size) {
+	while (count >= tape->buffer_size) {
 		bytes_read = idetape_add_chrdev_read_request(drive, ctl);
 		if (bytes_read <= 0)
 			goto finish;
-		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
-					       bytes_read))
+		if (idetape_copy_stage_to_user(tape, buf, bytes_read))
 			ret = -EFAULT;
 		buf += bytes_read;
 		count -= bytes_read;
@@ -2786,11 +2073,10 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
 		if (bytes_read <= 0)
 			goto finish;
 		temp = min((unsigned long)count, (unsigned long)bytes_read);
-		if (idetape_copy_stage_to_user(tape, buf, tape->merge_stage,
-					       temp))
+		if (idetape_copy_stage_to_user(tape, buf, temp))
 			ret = -EFAULT;
 		actually_read += temp;
-		tape->merge_stage_size = bytes_read-temp;
+		tape->merge_bh_size = bytes_read-temp;
 	}
 finish:
 	if (!actually_read && test_bit(IDETAPE_FLAG_FILEMARK, &tape->flags)) {
@@ -2821,17 +2107,17 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
 	/* Initialize write operation */
 	if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
 		if (tape->chrdev_dir == IDETAPE_DIR_READ)
-			idetape_discard_read_pipeline(drive, 1);
-		if (tape->merge_stage || tape->merge_stage_size) {
-			printk(KERN_ERR "ide-tape: merge_stage_size "
+			ide_tape_discard_merge_buffer(drive, 1);
+		if (tape->merge_bh || tape->merge_bh_size) {
+			printk(KERN_ERR "ide-tape: merge_bh_size "
 				"should be 0 now\n");
-			tape->merge_stage_size = 0;
+			tape->merge_bh_size = 0;
 		}
-		tape->merge_stage = __idetape_kmalloc_stage(tape, 0, 0);
-		if (!tape->merge_stage)
+		tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
+		if (!tape->merge_bh)
 			return -ENOMEM;
 		tape->chrdev_dir = IDETAPE_DIR_WRITE;
-		idetape_init_merge_stage(tape);
+		idetape_init_merge_buffer(tape);
 
 		/*
 		 * Issue a write 0 command to ensure that DSC handshake is
@@ -2842,10 +2128,10 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
 		if (drive->dsc_overlap) {
 			ssize_t retval = idetape_queue_rw_tail(drive,
 							REQ_IDETAPE_WRITE, 0,
-							tape->merge_stage->bh);
+							tape->merge_bh);
 			if (retval < 0) {
-				__idetape_kfree_stage(tape->merge_stage);
-				tape->merge_stage = NULL;
+				ide_tape_kfree_buffer(tape);
+				tape->merge_bh = NULL;
 				tape->chrdev_dir = IDETAPE_DIR_NONE;
 				return retval;
 			}
@@ -2853,49 +2139,44 @@ 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) {
+	if (tape->merge_bh_size) {
+		if (tape->merge_bh_size >= tape->buffer_size) {
 			printk(KERN_ERR "ide-tape: bug: merge buf too big\n");
-			tape->merge_stage_size = 0;
+			tape->merge_bh_size = 0;
 		}
 		actually_written = min((unsigned int)
-				(tape->stage_size - tape->merge_stage_size),
+				(tape->buffer_size - tape->merge_bh_size),
 				(unsigned int)count);
-		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
-						 actually_written))
+		if (idetape_copy_stage_from_user(tape, buf, actually_written))
 				ret = -EFAULT;
 		buf += actually_written;
-		tape->merge_stage_size += actually_written;
+		tape->merge_bh_size += actually_written;
 		count -= actually_written;
 
-		if (tape->merge_stage_size == tape->stage_size) {
+		if (tape->merge_bh_size == tape->buffer_size) {
 			ssize_t retval;
-			tape->merge_stage_size = 0;
+			tape->merge_bh_size = 0;
 			retval = idetape_add_chrdev_write_request(drive, ctl);
 			if (retval <= 0)
 				return (retval);
 		}
 	}
-	while (count >= tape->stage_size) {
+	while (count >= tape->buffer_size) {
 		ssize_t retval;
-		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
-						 tape->stage_size))
+		if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
 			ret = -EFAULT;
-		buf += tape->stage_size;
-		count -= tape->stage_size;
+		buf += tape->buffer_size;
+		count -= tape->buffer_size;
 		retval = idetape_add_chrdev_write_request(drive, ctl);
-		actually_written += tape->stage_size;
+		actually_written += tape->buffer_size;
 		if (retval <= 0)
 			return (retval);
 	}
 	if (count) {
 		actually_written += count;
-		if (idetape_copy_stage_from_user(tape, tape->merge_stage, buf,
-						 count))
+		if (idetape_copy_stage_from_user(tape, buf, count))
 			ret = -EFAULT;
-		tape->merge_stage_size += count;
+		tape->merge_bh_size += count;
 	}
 	return ret ? ret : actually_written;
 }
@@ -2919,8 +2200,7 @@ static int idetape_write_filemark(ide_drive_t *drive)
  *
  * Note: MTBSF and MTBSFM are not supported when the tape doesn't support
  * spacing over filemarks in the reverse direction. In this case, MTFSFM is also
- * usually not supported (it is supported in the rare case in which we crossed
- * the filemark during our read-ahead pipelined operation mode).
+ * usually not supported.
  *
  * The following commands are currently not supported:
  *
@@ -2936,7 +2216,6 @@ 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",
 			mt_op, mt_count);
 
-	/* Commands which need our pipelined read-ahead stages. */
 	switch (mt_op) {
 	case MTFSF:
 	case MTFSFM:
@@ -2953,7 +2232,7 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
 	case MTWEOF:
 		if (tape->write_prot)
 			return -EACCES;
-		idetape_discard_read_pipeline(drive, 1);
+		ide_tape_discard_merge_buffer(drive, 1);
 		for (i = 0; i < mt_count; i++) {
 			retval = idetape_write_filemark(drive);
 			if (retval)
@@ -2961,12 +2240,12 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
 		}
 		return 0;
 	case MTREW:
-		idetape_discard_read_pipeline(drive, 0);
+		ide_tape_discard_merge_buffer(drive, 0);
 		if (idetape_rewind_tape(drive))
 			return -EIO;
 		return 0;
 	case MTLOAD:
-		idetape_discard_read_pipeline(drive, 0);
+		ide_tape_discard_merge_buffer(drive, 0);
 		idetape_create_load_unload_cmd(drive, &pc,
 					       IDETAPE_LU_LOAD_MASK);
 		return idetape_queue_pc_tail(drive, &pc);
@@ -2981,7 +2260,7 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
 				if (!idetape_queue_pc_tail(drive, &pc))
 					tape->door_locked = DOOR_UNLOCKED;
 		}
-		idetape_discard_read_pipeline(drive, 0);
+		ide_tape_discard_merge_buffer(drive, 0);
 		idetape_create_load_unload_cmd(drive, &pc,
 					      !IDETAPE_LU_LOAD_MASK);
 		retval = idetape_queue_pc_tail(drive, &pc);
@@ -2989,10 +2268,10 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
 			clear_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags);
 		return retval;
 	case MTNOP:
-		idetape_discard_read_pipeline(drive, 0);
+		ide_tape_discard_merge_buffer(drive, 0);
 		return idetape_flush_tape_buffers(drive);
 	case MTRETEN:
-		idetape_discard_read_pipeline(drive, 0);
+		ide_tape_discard_merge_buffer(drive, 0);
 		idetape_create_load_unload_cmd(drive, &pc,
 			IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
 		return idetape_queue_pc_tail(drive, &pc);
@@ -3014,11 +2293,11 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
 			set_bit(IDETAPE_FLAG_DETECT_BS, &tape->flags);
 		return 0;
 	case MTSEEK:
-		idetape_discard_read_pipeline(drive, 0);
+		ide_tape_discard_merge_buffer(drive, 0);
 		return idetape_position_tape(drive,
 			mt_count * tape->user_bs_factor, tape->partition, 0);
 	case MTSETPART:
-		idetape_discard_read_pipeline(drive, 0);
+		ide_tape_discard_merge_buffer(drive, 0);
 		return idetape_position_tape(drive, 0, mt_count, 0);
 	case MTFSR:
 	case MTBSR:
@@ -3063,13 +2342,12 @@ 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);
+		ide_tape_flush_merge_buffer(drive);
 		idetape_flush_tape_buffers(drive);
 	}
 	if (cmd == MTIOCGET || cmd == MTIOCPOS) {
-		block_offset = idetape_pipeline_size(drive) /
+		block_offset = tape->merge_bh_size /
 			(tape->blk_size * tape->user_bs_factor);
 		position = idetape_read_position(drive);
 		if (position < 0)
@@ -3101,7 +2379,7 @@ static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
 		return 0;
 	default:
 		if (tape->chrdev_dir == IDETAPE_DIR_READ)
-			idetape_discard_read_pipeline(drive, 1);
+			ide_tape_discard_merge_buffer(drive, 1);
 		return idetape_blkdev_ioctl(drive, cmd, arg);
 	}
 }
@@ -3175,9 +2453,6 @@ static int idetape_chrdev_open(struct inode *inode, struct file *filp)
 	if (!test_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags))
 		(void)idetape_rewind_tape(drive);
 
-	if (tape->chrdev_dir != IDETAPE_DIR_READ)
-		clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
-
 	/* Read block size and write protect status from drive. */
 	ide_tape_get_bsize_from_bdesc(drive);
 
@@ -3206,8 +2481,6 @@ 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:
@@ -3219,13 +2492,13 @@ static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
 {
 	idetape_tape_t *tape = drive->driver_data;
 
-	idetape_empty_write_pipeline(drive);
-	tape->merge_stage = __idetape_kmalloc_stage(tape, 1, 0);
-	if (tape->merge_stage != NULL) {
+	ide_tape_flush_merge_buffer(drive);
+	tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
+	if (tape->merge_bh != NULL) {
 		idetape_pad_zeros(drive, tape->blk_size *
 				(tape->user_bs_factor - 1));
-		__idetape_kfree_stage(tape->merge_stage);
-		tape->merge_stage = NULL;
+		ide_tape_kfree_buffer(tape);
+		tape->merge_bh = NULL;
 	}
 	idetape_write_filemark(drive);
 	idetape_flush_tape_buffers(drive);
@@ -3248,14 +2521,9 @@ static int idetape_chrdev_release(struct inode *inode, struct file *filp)
 		idetape_write_release(drive, minor);
 	if (tape->chrdev_dir == IDETAPE_DIR_READ) {
 		if (minor < 128)
-			idetape_discard_read_pipeline(drive, 1);
-		else
-			idetape_wait_for_pipeline(drive);
-	}
-	if (tape->cache_stage != NULL) {
-		__idetape_kfree_stage(tape->cache_stage);
-		tape->cache_stage = NULL;
+			ide_tape_discard_merge_buffer(drive, 1);
 	}
+
 	if (minor < 128 && test_bit(IDETAPE_FLAG_MEDIUM_PRESENT, &tape->flags))
 		(void) idetape_rewind_tape(drive);
 	if (tape->chrdev_dir == IDETAPE_DIR_NONE) {
@@ -3392,33 +2660,15 @@ static void idetape_add_settings(ide_drive_t *drive)
 
 	ide_add_setting(drive, "buffer", SETTING_READ, TYPE_SHORT, 0, 0xffff,
 			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", SETTING_RW, TYPE_INT, 1, 0xffff,
-			tape->stage_size / 1024, 1, &tape->max_stages, NULL);
-	ide_add_setting(drive, "pipeline_max", SETTING_RW, TYPE_INT, 1,	0xffff,
-			tape->stage_size / 1024, 1, &tape->max_pipeline, NULL);
-	ide_add_setting(drive, "pipeline_used",	SETTING_READ, TYPE_INT, 0,
-			0xffff,	tape->stage_size / 1024, 1, &tape->nr_stages,
-			NULL);
-	ide_add_setting(drive, "pipeline_pending", SETTING_READ, TYPE_INT, 0,
-			0xffff, tape->stage_size / 1024, 1,
-			&tape->nr_pending_stages, NULL);
 	ide_add_setting(drive, "speed", SETTING_READ, TYPE_SHORT, 0, 0xffff,
 			1, 1, (u16 *)&tape->caps[14], NULL);
-	ide_add_setting(drive, "stage", SETTING_READ, TYPE_INT,	0, 0xffff, 1,
-			1024, &tape->stage_size, NULL);
+	ide_add_setting(drive, "buffer_size", SETTING_READ, TYPE_INT, 0, 0xffff,
+			1, 1024, &tape->buffer_size, NULL);
 	ide_add_setting(drive, "tdsc", SETTING_RW, TYPE_INT, IDETAPE_DSC_RW_MIN,
 			IDETAPE_DSC_RW_MAX, 1000, HZ, &tape->best_dsc_rw_freq,
 			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,
@@ -3441,11 +2691,10 @@ static inline void idetape_add_settings(ide_drive_t *drive) { ; }
  */
 static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
 {
-	unsigned long t1, tmid, tn, t;
+	unsigned long t;
 	int speed;
-	int stage_size;
+	int buffer_size;
 	u8 gcw[2];
-	struct sysinfo si;
 	u16 *ctl = (u16 *)&tape->caps[12];
 
 	spin_lock_init(&tape->lock);
@@ -3464,65 +2713,33 @@ 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 */
 	if (((gcw[0] & 0x60) >> 5) == 1)
 		set_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags);
 
-	tape->min_pipeline = 10;
-	tape->max_pipeline = 10;
-	tape->max_stages   = 10;
-
 	idetape_get_inquiry_results(drive);
 	idetape_get_mode_sense_results(drive);
 	ide_tape_get_bsize_from_bdesc(drive);
 	tape->user_bs_factor = 1;
-	tape->stage_size = *ctl * tape->blk_size;
-	while (tape->stage_size > 0xffff) {
+	tape->buffer_size = *ctl * tape->blk_size;
+	while (tape->buffer_size > 0xffff) {
 		printk(KERN_NOTICE "ide-tape: decreasing stage size\n");
 		*ctl /= 2;
-		tape->stage_size = *ctl * tape->blk_size;
+		tape->buffer_size = *ctl * tape->blk_size;
 	}
-	stage_size = tape->stage_size;
-	tape->pages_per_stage = stage_size / PAGE_SIZE;
-	if (stage_size % PAGE_SIZE) {
-		tape->pages_per_stage++;
-		tape->excess_bh_size = PAGE_SIZE - stage_size % PAGE_SIZE;
+	buffer_size = tape->buffer_size;
+	tape->pages_per_buffer = buffer_size / PAGE_SIZE;
+	if (buffer_size % PAGE_SIZE) {
+		tape->pages_per_buffer++;
+		tape->excess_bh_size = PAGE_SIZE - buffer_size % PAGE_SIZE;
 	}
 
-	/* Select the "best" DSC read/write polling freq and pipeline size. */
+	/* select the "best" DSC read/write polling freq */
 	speed = max(*(u16 *)&tape->caps[14], *(u16 *)&tape->caps[8]);
 
-	tape->max_stages = speed * 1000 * 10 / tape->stage_size;
-
-	/* Limit memory use for pipeline to 10% of physical memory */
-	si_meminfo(&si);
-	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   = min(tape->max_stages, IDETAPE_MAX_PIPELINE_STAGES);
-	tape->min_pipeline = min(tape->max_stages, IDETAPE_MIN_PIPELINE_STAGES);
-	tape->max_pipeline =
-		min(tape->max_stages * 2, IDETAPE_MAX_PIPELINE_STAGES);
-	if (tape->max_stages == 0) {
-		tape->max_stages   = 1;
-		tape->min_pipeline = 1;
-		tape->max_pipeline = 1;
-	}
-
-	t1 = (tape->stage_size * HZ) / (speed * 1000);
-	tmid = (*(u16 *)&tape->caps[16] * 32 * HZ) / (speed * 125);
-	tn = (IDETAPE_FIFO_THRESHOLD * tape->stage_size * HZ) / (speed * 1000);
-
-	if (tape->max_stages)
-		t = tn;
-	else
-		t = t1;
+	t = (IDETAPE_FIFO_THRESHOLD * tape->buffer_size * HZ) / (speed * 1000);
 
 	/*
 	 * Ensure that the number we got makes sense; limit it within
@@ -3532,11 +2749,10 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
 				min_t(unsigned long, t, IDETAPE_DSC_RW_MAX),
 				IDETAPE_DSC_RW_MIN);
 	printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
-		"%dkB pipeline, %lums tDSC%s\n",
+		"%lums tDSC%s\n",
 		drive->name, tape->name, *(u16 *)&tape->caps[14],
-		(*(u16 *)&tape->caps[16] * 512) / tape->stage_size,
-		tape->stage_size / 1024,
-		tape->max_stages * tape->stage_size / 1024,
+		(*(u16 *)&tape->caps[16] * 512) / tape->buffer_size,
+		tape->buffer_size / 1024,
 		tape->best_dsc_rw_freq * 1000 / HZ,
 		drive->using_dma ? ", DMA":"");
 
@@ -3560,7 +2776,7 @@ static void ide_tape_release(struct kref *kref)
 	ide_drive_t *drive = tape->drive;
 	struct gendisk *g = tape->disk;
 
-	BUG_ON(tape->first_stage != NULL || tape->merge_stage_size);
+	BUG_ON(tape->merge_bh_size);
 
 	drive->dsc_overlap = 0;
 	drive->driver_data = NULL;