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Message-Id: <200803210109.02044.bzolnier@gmail.com>
Date: Fri, 21 Mar 2008 01:09:01 +0100
From: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
To: Borislav Petkov <petkovbb@...glemail.com>
Cc: linux-kernel@...r.kernel.org, linux-ide@...r.kernel.org,
Borislav Petkov <petkovbb@...il.com>
Subject: Re: [PATCH 03/17] ide-tape: remove idetape_discard_read_pipeline()
On Monday 17 March 2008, Borislav Petkov wrote:
> Now that we don't queue any more requests on the pipeline we don't need to
> discard it anymore. Also, remove __idetape_discard_read_pipeline() too.
>
> Signed-off-by: Borislav Petkov <petkovbb@...il.com>
> ---
> drivers/ide/ide-tape.c | 92 +----------------------------------------------
> 1 files changed, 2 insertions(+), 90 deletions(-)
>
> diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
> index 241f596..429fed4 100644
> --- a/drivers/ide/ide-tape.c
> +++ b/drivers/ide/ide-tape.c
> @@ -1875,52 +1875,6 @@ static int idetape_create_prevent_cmd(ide_drive_t *drive,
> return 1;
> }
>
> -static int __idetape_discard_read_pipeline(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;
> -
> - /* 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;
->merge_stage_size is still used for accounting and we've just silently
deleted code modifying it...
> - if (tape->merge_stage != NULL) {
> - __idetape_kfree_stage(tape->merge_stage);
> - tape->merge_stage = NULL;
> - }
> -
> - /* Clear pipeline flags. */
> - clear_bit(IDETAPE_FLAG_PIPELINE_ERR, &tape->flags);
> - tape->chrdev_dir = IDETAPE_DIR_NONE;
ditto for ->merge_stage and ->chrdev_dir (!)
> - /* Remove pipeline stages. */
> - if (tape->first_stage == NULL)
> - return 0;
only code below could be safely deleted at the moment
(we know that ->first_stage is always NULL)
> - spin_lock_irqsave(&tape->lock, flags);
> - tape->next_stage = NULL;
> - if (test_bit(IDETAPE_FLAG_PIPELINE_ACTIVE, &tape->flags))
> - 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;
> -}
> -
> /*
> * Position the tape to the requested block using the LOCATE packet command.
> * A READ POSITION command is then issued to check where we are positioned. Like
> @@ -1930,12 +1884,9 @@ static int __idetape_discard_read_pipeline(ide_drive_t *drive)
> static int idetape_position_tape(ide_drive_t *drive, unsigned int block,
> u8 partition, int skip)
> {
> - idetape_tape_t *tape = drive->driver_data;
> - int retval;
> struct ide_atapi_pc pc;
> + int retval;
>
> - if (tape->chrdev_dir == IDETAPE_DIR_READ)
> - __idetape_discard_read_pipeline(drive);
> idetape_wait_ready(drive, 60 * 5 * HZ);
> idetape_create_locate_cmd(drive, &pc, block, partition, skip);
> retval = idetape_queue_pc_tail(drive, &pc);
> @@ -1946,25 +1897,6 @@ 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,
> - int restore_position)
> -{
> - idetape_tape_t *tape = drive->driver_data;
> - int cnt;
> - int seek, position;
> -
> - cnt = __idetape_discard_read_pipeline(drive);
> - if (restore_position) {
> - position = idetape_read_position(drive);
> - seek = position > cnt ? position - cnt : 0;
> - if (idetape_position_tape(drive, seek, 0, 0)) {
and here we've silently deleted idetape_position_tape() call
(for 'restore_position == 1' users)
I just skipped this patch => I had to slightly re-do later patches
while merging them...
> - printk(KERN_INFO "ide-tape: %s: position_tape failed in"
> - " discard_pipeline()\n", tape->name);
> - return;
> - }
> - }
> -}
> -
> /*
> * Generate a read/write request for the block device interface and wait for it
> * to be serviced.
> @@ -2406,11 +2338,6 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
> * 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);
> @@ -2423,7 +2350,6 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
> ++count;
> idetape_remove_stage_head(drive);
> }
> - idetape_discard_read_pipeline(drive, 0);
> }
>
> /*
> @@ -2547,8 +2473,6 @@ 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 "
> "should be 0 now\n");
> @@ -2675,7 +2599,6 @@ 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);
> for (i = 0; i < mt_count; i++) {
> retval = idetape_write_filemark(drive);
> if (retval)
> @@ -2683,12 +2606,10 @@ static int idetape_mtioctop(ide_drive_t *drive, short mt_op, int mt_count)
> }
> return 0;
> case MTREW:
> - idetape_discard_read_pipeline(drive, 0);
> if (idetape_rewind_tape(drive))
> return -EIO;
> return 0;
> case MTLOAD:
> - idetape_discard_read_pipeline(drive, 0);
> idetape_create_load_unload_cmd(drive, &pc,
> IDETAPE_LU_LOAD_MASK);
> return idetape_queue_pc_tail(drive, &pc);
> @@ -2703,7 +2624,6 @@ 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);
> idetape_create_load_unload_cmd(drive, &pc,
> !IDETAPE_LU_LOAD_MASK);
> retval = idetape_queue_pc_tail(drive, &pc);
> @@ -2711,10 +2631,8 @@ 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);
> return idetape_flush_tape_buffers(drive);
> case MTRETEN:
> - idetape_discard_read_pipeline(drive, 0);
> idetape_create_load_unload_cmd(drive, &pc,
> IDETAPE_LU_RETENSION_MASK | IDETAPE_LU_LOAD_MASK);
> return idetape_queue_pc_tail(drive, &pc);
> @@ -2736,11 +2654,9 @@ 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);
> return idetape_position_tape(drive,
> mt_count * tape->user_bs_factor, tape->partition, 0);
> case MTSETPART:
> - idetape_discard_read_pipeline(drive, 0);
> return idetape_position_tape(drive, 0, mt_count, 0);
> case MTFSR:
> case MTBSR:
> @@ -2821,8 +2737,6 @@ static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
> return -EFAULT;
> return 0;
> default:
> - if (tape->chrdev_dir == IDETAPE_DIR_READ)
> - idetape_discard_read_pipeline(drive, 1);
> return idetape_blkdev_ioctl(drive, cmd, arg);
> }
> }
> @@ -2966,9 +2880,7 @@ static int idetape_chrdev_release(struct inode *inode, struct file *filp)
> if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
> idetape_write_release(drive, minor);
> if (tape->chrdev_dir == IDETAPE_DIR_READ) {
> - if (minor < 128)
> - idetape_discard_read_pipeline(drive, 1);
> - else
> + if (minor >= 128)
> idetape_wait_for_pipeline(drive);
> }
--
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