ide: add ide_issue_pc() helper
[linux-2.6-block.git] / drivers / ide / ide-tape.c
index 0b8765c22d7ada5a38798b20ae95ebcf1140cd03..7907a1e41918491318c09f1aec042b77be0e552c 100644 (file)
@@ -144,9 +144,6 @@ enum {
 
 /*************************** End of tunable parameters ***********************/
 
-/* Read/Write error simulation */
-#define SIMULATE_ERRORS                        0
-
 /* tape directions */
 enum {
        IDETAPE_DIR_NONE  = (1 << 0),
@@ -215,13 +212,6 @@ enum {
        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.
@@ -309,9 +299,11 @@ typedef struct ide_tape_obj {
 
        /* Data buffer size chosen based on the tape's recommendation */
        int buffer_size;
-       idetape_stage_t *merge_stage;
+       /* 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;
@@ -400,13 +392,13 @@ static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                if (bh == NULL) {
                        printk(KERN_ERR "ide-tape: bh == NULL in "
                                "idetape_input_buffers\n");
-                       ide_atapi_discard_data(drive, bcount);
+                       ide_pad_transfer(drive, 0, bcount);
                        return;
                }
                count = min(
                        (unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
                        bcount);
-               HWIF(drive)->atapi_input_bytes(drive, bh->b_data +
+               drive->hwif->input_data(drive, NULL, bh->b_data +
                                        atomic_read(&bh->b_count), count);
                bcount -= count;
                atomic_add(count, &bh->b_count);
@@ -432,7 +424,7 @@ static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
                        return;
                }
                count = min((unsigned int)pc->b_count, (unsigned int)bcount);
-               HWIF(drive)->atapi_output_bytes(drive, pc->b_data, count);
+               drive->hwif->output_data(drive, NULL, pc->b_data, count);
                bcount -= count;
                pc->b_data += count;
                pc->b_count -= count;
@@ -511,18 +503,6 @@ static struct request *idetape_next_rq_storage(ide_drive_t *drive)
        return (&tape->rq_stack[tape->rq_stack_index++]);
 }
 
-static void idetape_init_pc(struct ide_atapi_pc *pc)
-{
-       memset(pc->c, 0, 12);
-       pc->retries = 0;
-       pc->flags = 0;
-       pc->req_xfer = 0;
-       pc->buf = pc->pc_buf;
-       pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
-       pc->bh = NULL;
-       pc->b_data = NULL;
-}
-
 /*
  * called on each failed packet command retry to analyze the request sense. We
  * currently do not utilize this information.
@@ -543,7 +523,7 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
        if (pc->flags & PC_FLAG_DMA_ERROR) {
                pc->xferred = pc->req_xfer -
                        tape->blk_size *
-                       be32_to_cpu(get_unaligned((u32 *)&sense[3]));
+                       get_unaligned_be32(&sense[3]);
                idetape_update_buffers(pc);
        }
 
@@ -585,9 +565,9 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
 }
 
 /* Free data buffers completely. */
-static void ide_tape_kfree_buffer(idetape_stage_t *stage)
+static void ide_tape_kfree_buffer(idetape_tape_t *tape)
 {
-       struct idetape_bh *prev_bh, *bh = stage->bh;
+       struct idetape_bh *prev_bh, *bh = tape->merge_bh;
 
        while (bh) {
                u32 size = bh->b_size;
@@ -605,7 +585,7 @@ static void ide_tape_kfree_buffer(idetape_stage_t *stage)
                bh = bh->b_reqnext;
                kfree(prev_bh);
        }
-       kfree(stage);
+       kfree(tape->merge_bh);
 }
 
 static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
@@ -639,21 +619,75 @@ static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
        return 0;
 }
 
-static ide_startstop_t idetape_request_sense_callback(ide_drive_t *drive)
+static void ide_tape_callback(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
+       struct ide_atapi_pc *pc = tape->pc;
+       int uptodate = pc->error ? 0 : 1;
 
        debug_log(DBG_PROCS, "Enter %s\n", __func__);
 
-       if (!tape->pc->error) {
-               idetape_analyze_error(drive, tape->pc->buf);
-               idetape_end_request(drive, 1, 0);
-       } else {
-               printk(KERN_ERR "ide-tape: Error in REQUEST SENSE itself - "
-                               "Aborting request!\n");
-               idetape_end_request(drive, 0, 0);
+       if (pc->c[0] == REQUEST_SENSE) {
+               if (uptodate)
+                       idetape_analyze_error(drive, pc->buf);
+               else
+                       printk(KERN_ERR "ide-tape: Error in REQUEST SENSE "
+                                       "itself - Aborting request!\n");
+       } else if (pc->c[0] == READ_6 || pc->c[0] == WRITE_6) {
+               struct request *rq = drive->hwif->hwgroup->rq;
+               int blocks = pc->xferred / tape->blk_size;
+
+               tape->avg_size += blocks * tape->blk_size;
+
+               if (time_after_eq(jiffies, tape->avg_time + HZ)) {
+                       tape->avg_speed = tape->avg_size * HZ /
+                               (jiffies - tape->avg_time) / 1024;
+                       tape->avg_size = 0;
+                       tape->avg_time = jiffies;
+               }
+
+               tape->first_frame += blocks;
+               rq->current_nr_sectors -= blocks;
+
+               if (pc->error)
+                       uptodate = pc->error;
+       } else if (pc->c[0] == READ_POSITION && uptodate) {
+               u8 *readpos = tape->pc->buf;
+
+               debug_log(DBG_SENSE, "BOP - %s\n",
+                               (readpos[0] & 0x80) ? "Yes" : "No");
+               debug_log(DBG_SENSE, "EOP - %s\n",
+                               (readpos[0] & 0x40) ? "Yes" : "No");
+
+               if (readpos[0] & 0x4) {
+                       printk(KERN_INFO "ide-tape: Block location is unknown"
+                                        "to the tape\n");
+                       clear_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
+                       uptodate = 0;
+               } else {
+                       debug_log(DBG_SENSE, "Block Location - %u\n",
+                                       be32_to_cpu(*(u32 *)&readpos[4]));
+
+                       tape->partition = readpos[1];
+                       tape->first_frame = be32_to_cpu(*(u32 *)&readpos[4]);
+                       set_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
+               }
        }
-       return ide_stopped;
+
+       idetape_end_request(drive, uptodate, 0);
+}
+
+static void idetape_init_pc(struct ide_atapi_pc *pc)
+{
+       memset(pc->c, 0, 12);
+       pc->retries = 0;
+       pc->flags = 0;
+       pc->req_xfer = 0;
+       pc->buf = pc->pc_buf;
+       pc->buf_size = IDETAPE_PC_BUFFER_SIZE;
+       pc->bh = NULL;
+       pc->b_data = NULL;
+       pc->callback = ide_tape_callback;
 }
 
 static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
@@ -662,12 +696,11 @@ static void idetape_create_request_sense_cmd(struct ide_atapi_pc *pc)
        pc->c[0] = REQUEST_SENSE;
        pc->c[4] = 20;
        pc->req_xfer = 20;
-       pc->idetape_callback = &idetape_request_sense_callback;
 }
 
 static void idetape_init_rq(struct request *rq, u8 cmd)
 {
-       memset(rq, 0, sizeof(*rq));
+       blk_rq_init(NULL, rq);
        rq->cmd_type = REQ_TYPE_SPECIAL;
        rq->cmd[0] = cmd;
 }
@@ -693,9 +726,10 @@ static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
        struct ide_tape_obj *tape = drive->driver_data;
 
        idetape_init_rq(rq, REQ_IDETAPE_PC1);
+       rq->cmd_flags |= REQ_PREEMPT;
        rq->buffer = (char *) pc;
        rq->rq_disk = tape->disk;
-       (void) ide_do_drive_cmd(drive, rq, ide_preempt);
+       ide_do_drive_cmd(drive, rq);
 }
 
 /*
@@ -703,7 +737,7 @@ static void idetape_queue_pc_head(ide_drive_t *drive, struct ide_atapi_pc *pc,
  *     last packet command. We queue a request sense packet command in
  *     the head of the request list.
  */
-static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
+static void idetape_retry_pc(ide_drive_t *drive)
 {
        idetape_tape_t *tape = drive->driver_data;
        struct ide_atapi_pc *pc;
@@ -715,7 +749,6 @@ static ide_startstop_t idetape_retry_pc (ide_drive_t *drive)
        idetape_create_request_sense_cmd(pc);
        set_bit(IDETAPE_FLAG_IGNORE_DSC, &tape->flags);
        idetape_queue_pc_head(drive, pc, rq);
-       return ide_stopped;
 }
 
 /*
@@ -749,9 +782,6 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
        xfer_func_t *xferfunc;
        idetape_io_buf *iobuf;
        unsigned int temp;
-#if SIMULATE_ERRORS
-       static int error_sim_count;
-#endif
        u16 bcount;
        u8 stat, ireason;
 
@@ -762,27 +792,6 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
 
        if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
                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
-                        * READ command, it will issue an irq and position
-                        * itself before the filemark, so that only a partial
-                        * data transfer will occur (which causes the DMA
-                        * error). In that case, we will later ask the tape
-                        * how much bytes of the original request were
-                        * actually transferred (we can't receive that
-                        * information from the DMA engine on most chipsets).
-                        */
-
-                       /*
-                        * On the contrary, a DMA error is never expected;
-                        * it usually indicates a hardware error or abort.
-                        * If the tape crosses a filemark during a READ
-                        * command, it will issue an irq and position itself
-                        * after the filemark (not before). Only a partial
-                        * data transfer will occur, but no DMA error.
-                        * (AS, 19 Apr 2001)
-                        */
                        pc->flags |= PC_FLAG_DMA_ERROR;
                } else {
                        pc->xferred = pc->req_xfer;
@@ -798,16 +807,8 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
                                " transferred\n", pc->xferred);
 
                pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
-               local_irq_enable();
+               local_irq_enable_in_hardirq();
 
-#if SIMULATE_ERRORS
-               if ((pc->c[0] == WRITE_6 || pc->c[0] == READ_6) &&
-                   (++error_sim_count % 100) == 0) {
-                       printk(KERN_INFO "ide-tape: %s: simulating error\n",
-                               tape->name);
-                       stat |= ERR_STAT;
-               }
-#endif
                if ((stat & ERR_STAT) && pc->c[0] == REQUEST_SENSE)
                        stat &= ~ERR_STAT;
                if ((stat & ERR_STAT) || (pc->flags & PC_FLAG_DMA_ERROR)) {
@@ -815,15 +816,16 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
                        debug_log(DBG_ERR, "%s: I/O error\n", tape->name);
 
                        if (pc->c[0] == REQUEST_SENSE) {
-                               printk(KERN_ERR "ide-tape: I/O error in request"
-                                               " sense command\n");
+                               printk(KERN_ERR "%s: I/O error in request sense"
+                                               " command\n", drive->name);
                                return ide_do_reset(drive);
                        }
                        debug_log(DBG_ERR, "[cmd %x]: check condition\n",
                                        pc->c[0]);
 
                        /* Retry operation */
-                       return idetape_retry_pc(drive);
+                       idetape_retry_pc(drive);
+                       return ide_stopped;
                }
                pc->error = 0;
                if ((pc->flags & PC_FLAG_WAIT_FOR_DSC) &&
@@ -839,14 +841,14 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
                if (tape->failed_pc == pc)
                        tape->failed_pc = NULL;
                /* Command finished - Call the callback function */
-               return pc->idetape_callback(drive);
+               pc->callback(drive);
+               return ide_stopped;
        }
 
        if (pc->flags & PC_FLAG_DMA_IN_PROGRESS) {
                pc->flags &= ~PC_FLAG_DMA_IN_PROGRESS;
-               printk(KERN_ERR "ide-tape: The tape wants to issue more "
-                               "interrupts in DMA mode\n");
-               printk(KERN_ERR "ide-tape: DMA disabled, reverting to PIO\n");
+               printk(KERN_ERR "%s: The device wants to issue more interrupts "
+                               "in DMA mode\n", drive->name);
                ide_dma_off(drive);
                return ide_do_reset(drive);
        }
@@ -857,14 +859,14 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
        ireason = hwif->INB(hwif->io_ports.nsect_addr);
 
        if (ireason & CD) {
-               printk(KERN_ERR "ide-tape: CoD != 0 in %s\n", __func__);
+               printk(KERN_ERR "%s: CoD != 0 in %s\n", drive->name, __func__);
                return ide_do_reset(drive);
        }
        if (((ireason & IO) == IO) == !!(pc->flags & PC_FLAG_WRITING)) {
                /* Hopefully, we will never get here */
-               printk(KERN_ERR "ide-tape: We wanted to %s, ",
-                               (ireason & IO) ? "Write" : "Read");
-               printk(KERN_ERR "ide-tape: but the tape wants us to %s !\n",
+               printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
+                               "to %s!\n", drive->name,
+                               (ireason & IO) ? "Write" : "Read",
                                (ireason & IO) ? "Read" : "Write");
                return ide_do_reset(drive);
        }
@@ -873,28 +875,29 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
                temp = pc->xferred + bcount;
                if (temp > pc->req_xfer) {
                        if (temp > pc->buf_size) {
-                               printk(KERN_ERR "ide-tape: The tape wants to "
-                                       "send us more data than expected "
-                                       "- discarding data\n");
-                               ide_atapi_discard_data(drive, bcount);
+                               printk(KERN_ERR "%s: The device wants to send "
+                                               "us more data than expected - "
+                                               "discarding data\n",
+                                               drive->name);
+                               ide_pad_transfer(drive, 0, bcount);
                                ide_set_handler(drive, &idetape_pc_intr,
                                                IDETAPE_WAIT_CMD, NULL);
                                return ide_started;
                        }
-                       debug_log(DBG_SENSE, "The tape wants to send us more "
+                       debug_log(DBG_SENSE, "The device wants to send us more "
                                "data than expected - allowing transfer\n");
                }
                iobuf = &idetape_input_buffers;
-               xferfunc = hwif->atapi_input_bytes;
+               xferfunc = hwif->input_data;
        } else {
                iobuf = &idetape_output_buffers;
-               xferfunc = hwif->atapi_output_bytes;
+               xferfunc = hwif->output_data;
        }
 
        if (pc->bh)
                iobuf(drive, pc, bcount);
        else
-               xferfunc(drive, pc->cur_pos, bcount);
+               xferfunc(drive, NULL, pc->cur_pos, bcount);
 
        /* Update the current position */
        pc->xferred += bcount;
@@ -946,55 +949,16 @@ static ide_startstop_t idetape_pc_intr(ide_drive_t *drive)
  */
 static ide_startstop_t idetape_transfer_pc(ide_drive_t *drive)
 {
-       ide_hwif_t *hwif = drive->hwif;
        idetape_tape_t *tape = drive->driver_data;
-       struct ide_atapi_pc *pc = tape->pc;
-       int retries = 100;
-       ide_startstop_t startstop;
-       u8 ireason;
 
-       if (ide_wait_stat(&startstop, drive, DRQ_STAT, BUSY_STAT, WAIT_READY)) {
-               printk(KERN_ERR "ide-tape: Strange, packet command initiated "
-                               "yet DRQ isn't asserted\n");
-               return startstop;
-       }
-       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.nsect_addr);
-               if (retries == 0) {
-                       printk(KERN_ERR "ide-tape: (IO,CoD != (0,1) while "
-                                       "issuing a packet command, ignoring\n");
-                       ireason |= CD;
-                       ireason &= ~IO;
-               }
-       }
-       if ((ireason & CD) == 0 || (ireason & IO)) {
-               printk(KERN_ERR "ide-tape: (IO,CoD) != (0,1) while issuing "
-                               "a packet command\n");
-               return ide_do_reset(drive);
-       }
-       /* Set the interrupt routine */
-       ide_set_handler(drive, &idetape_pc_intr, IDETAPE_WAIT_CMD, NULL);
-#ifdef CONFIG_BLK_DEV_IDEDMA
-       /* Begin DMA, if necessary */
-       if (pc->flags & PC_FLAG_DMA_IN_PROGRESS)
-               hwif->dma_ops->dma_start(drive);
-#endif
-       /* Send the actual packet */
-       HWIF(drive)->atapi_output_bytes(drive, pc->c, 12);
-       return ide_started;
+       return ide_transfer_pc(drive, tape->pc, idetape_pc_intr,
+                              IDETAPE_WAIT_CMD, NULL);
 }
 
 static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
                struct ide_atapi_pc *pc)
 {
-       ide_hwif_t *hwif = drive->hwif;
        idetape_tape_t *tape = drive->driver_data;
-       int dma_ok = 0;
-       u16 bcount;
 
        if (tape->pc->c[0] == REQUEST_SENSE &&
            pc->c[0] == REQUEST_SENSE) {
@@ -1029,50 +993,15 @@ static ide_startstop_t idetape_issue_pc(ide_drive_t *drive,
                        pc->error = IDETAPE_ERROR_GENERAL;
                }
                tape->failed_pc = NULL;
-               return pc->idetape_callback(drive);
+               pc->callback(drive);
+               return ide_stopped;
        }
        debug_log(DBG_SENSE, "Retry #%d, cmd = %02X\n", pc->retries, pc->c[0]);
 
        pc->retries++;
-       /* We haven't transferred any data yet */
-       pc->xferred = 0;
-       pc->cur_pos = pc->buf;
-       /* Request to transfer the entire buffer at once */
-       bcount = pc->req_xfer;
 
-       if (pc->flags & PC_FLAG_DMA_ERROR) {
-               pc->flags &= ~PC_FLAG_DMA_ERROR;
-               printk(KERN_WARNING "ide-tape: DMA disabled, "
-                               "reverting to PIO\n");
-               ide_dma_off(drive);
-       }
-       if ((pc->flags & PC_FLAG_DMA_RECOMMENDED) && drive->using_dma)
-               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);
-
-       if (dma_ok)
-               /* Will begin DMA later */
-               pc->flags |= PC_FLAG_DMA_IN_PROGRESS;
-       if (test_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags)) {
-               ide_execute_command(drive, WIN_PACKETCMD, &idetape_transfer_pc,
-                                   IDETAPE_WAIT_CMD, NULL);
-               return ide_started;
-       } else {
-               hwif->OUTB(WIN_PACKETCMD, hwif->io_ports.command_addr);
-               return idetape_transfer_pc(drive);
-       }
-}
-
-static ide_startstop_t idetape_pc_callback(ide_drive_t *drive)
-{
-       idetape_tape_t *tape = drive->driver_data;
-
-       debug_log(DBG_PROCS, "Enter %s\n", __func__);
-
-       idetape_end_request(drive, tape->pc->error ? 0 : 1, 0);
-       return ide_stopped;
+       return ide_issue_pc(drive, pc, idetape_transfer_pc,
+                           IDETAPE_WAIT_CMD, NULL);
 }
 
 /* A mode sense command is used to "sense" tape parameters. */
@@ -1100,7 +1029,6 @@ static void idetape_create_mode_sense_cmd(struct ide_atapi_pc *pc, u8 page_code)
                pc->req_xfer = 24;
        else
                pc->req_xfer = 50;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
@@ -1118,7 +1046,8 @@ static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
                                printk(KERN_ERR "ide-tape: %s: I/O error, ",
                                                tape->name);
                        /* Retry operation */
-                       return idetape_retry_pc(drive);
+                       idetape_retry_pc(drive);
+                       return ide_stopped;
                }
                pc->error = 0;
                if (tape->failed_pc == pc)
@@ -1127,32 +1056,7 @@ static ide_startstop_t idetape_media_access_finished(ide_drive_t *drive)
                pc->error = IDETAPE_ERROR_GENERAL;
                tape->failed_pc = NULL;
        }
-       return pc->idetape_callback(drive);
-}
-
-static ide_startstop_t idetape_rw_callback(ide_drive_t *drive)
-{
-       idetape_tape_t *tape = drive->driver_data;
-       struct request *rq = HWGROUP(drive)->rq;
-       int blocks = tape->pc->xferred / tape->blk_size;
-
-       tape->avg_size += blocks * tape->blk_size;
-
-       if (time_after_eq(jiffies, tape->avg_time + HZ)) {
-               tape->avg_speed = tape->avg_size * HZ /
-                               (jiffies - tape->avg_time) / 1024;
-               tape->avg_size = 0;
-               tape->avg_time = jiffies;
-       }
-       debug_log(DBG_PROCS, "Enter %s\n", __func__);
-
-       tape->first_frame += blocks;
-       rq->current_nr_sectors -= blocks;
-
-       if (!tape->pc->error)
-               idetape_end_request(drive, 1, 0);
-       else
-               idetape_end_request(drive, tape->pc->error, 0);
+       pc->callback(drive);
        return ide_stopped;
 }
 
@@ -1164,14 +1068,13 @@ static void idetape_create_read_cmd(idetape_tape_t *tape,
        pc->c[0] = READ_6;
        put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
        pc->c[1] = 1;
-       pc->idetape_callback = &idetape_rw_callback;
        pc->bh = bh;
        atomic_set(&bh->b_count, 0);
        pc->buf = NULL;
        pc->buf_size = length * tape->blk_size;
        pc->req_xfer = pc->buf_size;
        if (pc->req_xfer == tape->buffer_size)
-               pc->flags |= PC_FLAG_DMA_RECOMMENDED;
+               pc->flags |= PC_FLAG_DMA_OK;
 }
 
 static void idetape_create_write_cmd(idetape_tape_t *tape,
@@ -1182,7 +1085,6 @@ static void idetape_create_write_cmd(idetape_tape_t *tape,
        pc->c[0] = WRITE_6;
        put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
        pc->c[1] = 1;
-       pc->idetape_callback = &idetape_rw_callback;
        pc->flags |= PC_FLAG_WRITING;
        pc->bh = bh;
        pc->b_data = bh->b_data;
@@ -1191,7 +1093,7 @@ static void idetape_create_write_cmd(idetape_tape_t *tape,
        pc->buf_size = length * tape->blk_size;
        pc->req_xfer = pc->buf_size;
        if (pc->req_xfer == tape->buffer_size)
-               pc->flags |= PC_FLAG_DMA_RECOMMENDED;
+               pc->flags |= PC_FLAG_DMA_OK;
 }
 
 static ide_startstop_t idetape_do_request(ide_drive_t *drive,
@@ -1215,8 +1117,10 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
        }
 
        /* Retry a failed packet command */
-       if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE)
-               return idetape_issue_pc(drive, tape->failed_pc);
+       if (tape->failed_pc && tape->pc->c[0] == REQUEST_SENSE) {
+               pc = tape->failed_pc;
+               goto out;
+       }
 
        if (postponed_rq != NULL)
                if (rq != postponed_rq) {
@@ -1288,6 +1192,9 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
        }
        BUG();
 out:
+       if (test_bit(IDETAPE_FLAG_DRQ_INTERRUPT, &tape->flags))
+               pc->flags |= PC_FLAG_DRQ_INTERRUPT;
+
        return idetape_issue_pc(drive, pc);
 }
 
@@ -1299,22 +1206,16 @@ out:
  * It returns a pointer to the newly allocated buffer, or NULL in case of
  * failure.
  */
-static idetape_stage_t *ide_tape_kmalloc_buffer(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;
+       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;
 
@@ -1374,9 +1275,9 @@ static idetape_stage_t *ide_tape_kmalloc_buffer(idetape_tape_t *tape, int full,
        bh->b_size -= tape->excess_bh_size;
        if (full)
                atomic_sub(tape->excess_bh_size, &bh->b_count);
-       return stage;
+       return merge_bh;
 abort:
-       ide_tape_kfree_buffer(stage);
+       ide_tape_kfree_buffer(tape);
        return NULL;
 }
 
@@ -1444,11 +1345,11 @@ 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 {
@@ -1457,40 +1358,6 @@ static void idetape_init_merge_stage(idetape_tape_t *tape)
        }
 }
 
-static ide_startstop_t idetape_read_position_callback(ide_drive_t *drive)
-{
-       idetape_tape_t *tape = drive->driver_data;
-       u8 *readpos = tape->pc->buf;
-
-       debug_log(DBG_PROCS, "Enter %s\n", __func__);
-
-       if (!tape->pc->error) {
-               debug_log(DBG_SENSE, "BOP - %s\n",
-                               (readpos[0] & 0x80) ? "Yes" : "No");
-               debug_log(DBG_SENSE, "EOP - %s\n",
-                               (readpos[0] & 0x40) ? "Yes" : "No");
-
-               if (readpos[0] & 0x4) {
-                       printk(KERN_INFO "ide-tape: Block location is unknown"
-                                        "to the tape\n");
-                       clear_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
-                       idetape_end_request(drive, 0, 0);
-               } else {
-                       debug_log(DBG_SENSE, "Block Location - %u\n",
-                                       be32_to_cpu(*(u32 *)&readpos[4]));
-
-                       tape->partition = readpos[1];
-                       tape->first_frame =
-                               be32_to_cpu(*(u32 *)&readpos[4]);
-                       set_bit(IDETAPE_FLAG_ADDRESS_VALID, &tape->flags);
-                       idetape_end_request(drive, 1, 0);
-               }
-       } else {
-               idetape_end_request(drive, 0, 0);
-       }
-       return ide_stopped;
-}
-
 /*
  * Write a filemark if write_filemark=1. Flush the device buffers without
  * writing a filemark otherwise.
@@ -1502,14 +1369,12 @@ static void idetape_create_write_filemark_cmd(ide_drive_t *drive,
        pc->c[0] = WRITE_FILEMARKS;
        pc->c[4] = write_filemark;
        pc->flags |= PC_FLAG_WAIT_FOR_DSC;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 static void idetape_create_test_unit_ready_cmd(struct ide_atapi_pc *pc)
 {
        idetape_init_pc(pc);
        pc->c[0] = TEST_UNIT_READY;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 /*
@@ -1528,12 +1393,16 @@ static void idetape_create_test_unit_ready_cmd(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;
+       struct request *rq;
+       int error;
 
-       idetape_init_rq(&rq, REQ_IDETAPE_PC1);
-       rq.buffer = (char *) pc;
-       rq.rq_disk = tape->disk;
-       return ide_do_drive_cmd(drive, &rq, ide_wait);
+       rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
+       rq->cmd_type = REQ_TYPE_SPECIAL;
+       rq->cmd[0] = REQ_IDETAPE_PC1;
+       rq->buffer = (char *)pc;
+       error = blk_execute_rq(drive->queue, tape->disk, rq, 0);
+       blk_put_request(rq);
+       return error;
 }
 
 static void idetape_create_load_unload_cmd(ide_drive_t *drive,
@@ -1543,7 +1412,6 @@ static void idetape_create_load_unload_cmd(ide_drive_t *drive,
        pc->c[0] = START_STOP;
        pc->c[4] = cmd;
        pc->flags |= PC_FLAG_WAIT_FOR_DSC;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 static int idetape_wait_ready(ide_drive_t *drive, unsigned long timeout)
@@ -1595,7 +1463,6 @@ static void idetape_create_read_position_cmd(struct ide_atapi_pc *pc)
        idetape_init_pc(pc);
        pc->c[0] = READ_POSITION;
        pc->req_xfer = 20;
-       pc->idetape_callback = &idetape_read_position_callback;
 }
 
 static int idetape_read_position(ide_drive_t *drive)
@@ -1623,7 +1490,6 @@ static void idetape_create_locate_cmd(ide_drive_t *drive,
        put_unaligned(cpu_to_be32(block), (unsigned int *) &pc->c[3]);
        pc->c[8] = partition;
        pc->flags |= PC_FLAG_WAIT_FOR_DSC;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 static int idetape_create_prevent_cmd(ide_drive_t *drive,
@@ -1638,7 +1504,6 @@ static int idetape_create_prevent_cmd(ide_drive_t *drive,
        idetape_init_pc(pc);
        pc->c[0] = ALLOW_MEDIUM_REMOVAL;
        pc->c[4] = prevent;
-       pc->idetape_callback = &idetape_pc_callback;
        return 1;
 }
 
@@ -1651,9 +1516,9 @@ static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
 
        clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
        tape->merge_bh_size = 0;
-       if (tape->merge_stage != NULL) {
-               ide_tape_kfree_buffer(tape->merge_stage);
-               tape->merge_stage = NULL;
+       if (tape->merge_bh != NULL) {
+               ide_tape_kfree_buffer(tape);
+               tape->merge_bh = NULL;
        }
 
        tape->chrdev_dir = IDETAPE_DIR_NONE;
@@ -1710,26 +1575,33 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
                                 struct idetape_bh *bh)
 {
        idetape_tape_t *tape = drive->driver_data;
-       struct request rq;
+       struct request *rq;
+       int ret, errors;
 
        debug_log(DBG_SENSE, "%s: cmd=%d\n", __func__, cmd);
 
-       idetape_init_rq(&rq, cmd);
-       rq.rq_disk = tape->disk;
-       rq.special = (void *)bh;
-       rq.sector = tape->first_frame;
-       rq.nr_sectors           = blocks;
-       rq.current_nr_sectors   = blocks;
-       (void) ide_do_drive_cmd(drive, &rq, ide_wait);
+       rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
+       rq->cmd_type = REQ_TYPE_SPECIAL;
+       rq->cmd[0] = cmd;
+       rq->rq_disk = tape->disk;
+       rq->special = (void *)bh;
+       rq->sector = tape->first_frame;
+       rq->nr_sectors = blocks;
+       rq->current_nr_sectors = blocks;
+       blk_execute_rq(drive->queue, tape->disk, rq, 0);
+
+       errors = rq->errors;
+       ret = tape->blk_size * (blocks - rq->current_nr_sectors);
+       blk_put_request(rq);
 
        if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
                return 0;
 
-       if (tape->merge_stage)
-               idetape_init_merge_stage(tape);
-       if (rq.errors == IDETAPE_ERROR_GENERAL)
+       if (tape->merge_bh)
+               idetape_init_merge_buffer(tape);
+       if (errors == IDETAPE_ERROR_GENERAL)
                return -EIO;
-       return (tape->blk_size * (blocks-rq.current_nr_sectors));
+       return ret;
 }
 
 static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
@@ -1738,7 +1610,6 @@ static void idetape_create_inquiry_cmd(struct ide_atapi_pc *pc)
        pc->c[0] = INQUIRY;
        pc->c[4] = 254;
        pc->req_xfer = 254;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 static void idetape_create_rewind_cmd(ide_drive_t *drive,
@@ -1747,7 +1618,6 @@ static void idetape_create_rewind_cmd(ide_drive_t *drive,
        idetape_init_pc(pc);
        pc->c[0] = REZERO_UNIT;
        pc->flags |= PC_FLAG_WAIT_FOR_DSC;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
@@ -1756,7 +1626,6 @@ static void idetape_create_erase_cmd(struct ide_atapi_pc *pc)
        pc->c[0] = ERASE;
        pc->c[1] = 1;
        pc->flags |= PC_FLAG_WAIT_FOR_DSC;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
@@ -1766,7 +1635,6 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
        put_unaligned(cpu_to_be32(count), (unsigned int *) &pc->c[1]);
        pc->c[1] = cmd;
        pc->flags |= PC_FLAG_WAIT_FOR_DSC;
-       pc->idetape_callback = &idetape_pc_callback;
 }
 
 /* Queue up a character device originated write request. */
@@ -1777,7 +1645,7 @@ static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
        debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
 
        return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
-                                    blocks, tape->merge_stage->bh);
+                                    blocks, tape->merge_bh);
 }
 
 static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
@@ -1787,7 +1655,7 @@ static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
        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;
        }
@@ -1827,9 +1695,9 @@ static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
                (void) idetape_add_chrdev_write_request(drive, blocks);
                tape->merge_bh_size = 0;
        }
-       if (tape->merge_stage != NULL) {
-               ide_tape_kfree_buffer(tape->merge_stage);
-               tape->merge_stage = NULL;
+       if (tape->merge_bh != NULL) {
+               ide_tape_kfree_buffer(tape);
+               tape->merge_bh = NULL;
        }
        tape->chrdev_dir = IDETAPE_DIR_NONE;
 }
@@ -1845,13 +1713,13 @@ static int idetape_init_read(ide_drive_t *drive)
                        ide_tape_flush_merge_buffer(drive);
                        idetape_flush_tape_buffers(drive);
                }
-               if (tape->merge_stage || tape->merge_bh_size) {
+               if (tape->merge_bh || tape->merge_bh_size) {
                        printk(KERN_ERR "ide-tape: merge_bh_size should be"
                                         " 0 now\n");
                        tape->merge_bh_size = 0;
                }
-               tape->merge_stage = ide_tape_kmalloc_buffer(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;
 
@@ -1864,10 +1732,10 @@ static int idetape_init_read(ide_drive_t *drive)
                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) {
-                               ide_tape_kfree_buffer(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;
                        }
@@ -1891,7 +1759,7 @@ static int idetape_add_chrdev_read_request(ide_drive_t *drive, int blocks)
        idetape_init_read(drive);
 
        return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks,
-                                    tape->merge_stage->bh);
+                                    tape->merge_bh);
 }
 
 static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
@@ -1903,7 +1771,7 @@ static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
        while (bcount) {
                unsigned int count;
 
-               bh = tape->merge_stage->bh;
+               bh = tape->merge_bh;
                count = min(tape->buffer_size, bcount);
                bcount -= count;
                blocks = count / tape->blk_size;
@@ -1915,7 +1783,7 @@ 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);
        }
 }
 
@@ -2000,10 +1868,6 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
                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:
@@ -2123,16 +1987,16 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
        if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
                if (tape->chrdev_dir == IDETAPE_DIR_READ)
                        ide_tape_discard_merge_buffer(drive, 1);
-               if (tape->merge_stage || tape->merge_bh_size) {
+               if (tape->merge_bh || tape->merge_bh_size) {
                        printk(KERN_ERR "ide-tape: merge_bh_size "
                                "should be 0 now\n");
                        tape->merge_bh_size = 0;
                }
-               tape->merge_stage = ide_tape_kmalloc_buffer(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
@@ -2143,10 +2007,10 @@ 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) {
-                               ide_tape_kfree_buffer(tape->merge_stage);
-                               tape->merge_stage = NULL;
+                               ide_tape_kfree_buffer(tape);
+                               tape->merge_bh = NULL;
                                tape->chrdev_dir = IDETAPE_DIR_NONE;
                                return retval;
                        }
@@ -2508,12 +2372,12 @@ static void idetape_write_release(ide_drive_t *drive, unsigned int minor)
        idetape_tape_t *tape = drive->driver_data;
 
        ide_tape_flush_merge_buffer(drive);
-       tape->merge_stage = ide_tape_kmalloc_buffer(tape, 1, 0);
-       if (tape->merge_stage != NULL) {
+       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));
-               ide_tape_kfree_buffer(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);
@@ -2760,9 +2624,8 @@ static void idetape_setup(ide_drive_t *drive, idetape_tape_t *tape, int minor)
         * Ensure that the number we got makes sense; limit it within
         * IDETAPE_DSC_RW_MIN and IDETAPE_DSC_RW_MAX.
         */
-       tape->best_dsc_rw_freq = max_t(unsigned long,
-                               min_t(unsigned long, t, IDETAPE_DSC_RW_MAX),
-                               IDETAPE_DSC_RW_MIN);
+       tape->best_dsc_rw_freq = clamp_t(unsigned long, t, IDETAPE_DSC_RW_MIN,
+                                        IDETAPE_DSC_RW_MAX);
        printk(KERN_INFO "ide-tape: %s <-> %s: %dKBps, %d*%dkB buffer, "
                "%lums tDSC%s\n",
                drive->name, tape->name, *(u16 *)&tape->caps[14],
@@ -2914,11 +2777,6 @@ static int ide_tape_probe(ide_drive_t *drive)
                                " the driver\n", drive->name);
                goto failed;
        }
-       if (drive->scsi) {
-               printk(KERN_INFO "ide-tape: passing drive %s to ide-scsi"
-                                " emulation.\n", drive->name);
-               goto failed;
-       }
        tape = kzalloc(sizeof(idetape_tape_t), GFP_KERNEL);
        if (tape == NULL) {
                printk(KERN_ERR "ide-tape: %s: Can't allocate a tape struct\n",