forked from Minki/linux
ide-tape: simplify read/write functions
Impact: cleanup idetape_chrdev_read/write() functions are unnecessarily complex when everything can be handled in a single loop. Collapse idetape_add_chrdev_read/write_request() into the rw functions and simplify the implementation. Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo
Jens Axboe
parent
71294cf93d
commit
4344d07fb8
@ -953,14 +953,6 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
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pc->flags |= PC_FLAG_WAIT_FOR_DSC;
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}
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/* Queue up a character device originated write request. */
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static int idetape_add_chrdev_write_request(ide_drive_t *drive, int size)
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{
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debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
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return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, size);
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}
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static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
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{
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idetape_tape_t *tape = drive->driver_data;
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@ -974,7 +966,7 @@ static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
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size_t aligned = roundup(tape->valid, tape->blk_size);
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memset(tape->cur, 0, aligned - tape->valid);
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idetape_add_chrdev_write_request(drive, aligned);
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idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, aligned);
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kfree(tape->buf);
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tape->buf = NULL;
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}
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@ -1031,20 +1023,6 @@ static int idetape_init_rw(ide_drive_t *drive, int dir)
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return 0;
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}
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/* called from idetape_chrdev_read() to service a chrdev read request. */
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static int idetape_add_chrdev_read_request(ide_drive_t *drive, int size)
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{
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debug_log(DBG_PROCS, "Enter %s, %d bytes\n", __func__, size);
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/* If we are at a filemark, return a read length of 0 */
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if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
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return 0;
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idetape_init_rw(drive, IDETAPE_DIR_READ);
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return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, size);
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}
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static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
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{
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idetape_tape_t *tape = drive->driver_data;
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@ -1184,8 +1162,9 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
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{
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struct ide_tape_obj *tape = file->private_data;
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ide_drive_t *drive = tape->drive;
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ssize_t bytes_read, temp, actually_read = 0, rc;
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size_t done = 0;
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ssize_t ret = 0;
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int rc;
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debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);
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@ -1195,52 +1174,43 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
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(count % tape->blk_size) == 0)
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tape->user_bs_factor = count / tape->blk_size;
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}
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rc = idetape_init_rw(drive, IDETAPE_DIR_READ);
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if (rc < 0)
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return rc;
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if (count == 0)
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return (0);
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if (tape->valid) {
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actually_read = min_t(unsigned int, tape->valid, count);
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if (copy_to_user(buf, tape->cur, actually_read))
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while (done < count) {
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size_t todo;
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/* refill if staging buffer is empty */
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if (!tape->valid) {
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/* If we are at a filemark, nothing more to read */
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if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
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break;
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/* read */
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if (idetape_queue_rw_tail(drive, REQ_IDETAPE_READ,
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tape->buffer_size) <= 0)
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break;
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}
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/* copy out */
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todo = min_t(size_t, count - done, tape->valid);
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if (copy_to_user(buf + done, tape->cur, todo))
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ret = -EFAULT;
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buf += actually_read;
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count -= actually_read;
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tape->cur += actually_read;
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tape->valid -= actually_read;
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tape->cur += todo;
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tape->valid -= todo;
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done += todo;
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}
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while (count >= tape->buffer_size) {
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bytes_read = idetape_add_chrdev_read_request(drive,
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tape->buffer_size);
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if (bytes_read <= 0)
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goto finish;
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if (copy_to_user(buf, tape->cur, bytes_read))
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ret = -EFAULT;
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buf += bytes_read;
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count -= bytes_read;
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actually_read += bytes_read;
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}
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if (count) {
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bytes_read = idetape_add_chrdev_read_request(drive,
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tape->buffer_size);
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if (bytes_read <= 0)
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goto finish;
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temp = min((unsigned long)count, (unsigned long)bytes_read);
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if (copy_to_user(buf, tape->cur, temp))
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ret = -EFAULT;
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actually_read += temp;
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tape->cur += temp;
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tape->valid -= temp;
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}
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finish:
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if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
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if (!done && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
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debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);
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idetape_space_over_filemarks(drive, MTFSF, 1);
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return 0;
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}
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return ret ? ret : actually_read;
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return ret ? ret : done;
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}
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static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
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@ -1248,7 +1218,7 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
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{
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struct ide_tape_obj *tape = file->private_data;
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ide_drive_t *drive = tape->drive;
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ssize_t actually_written = 0;
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size_t done = 0;
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ssize_t ret = 0;
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int rc;
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@ -1262,47 +1232,28 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
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rc = idetape_init_rw(drive, IDETAPE_DIR_WRITE);
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if (rc < 0)
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return rc;
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if (count == 0)
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return (0);
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if (tape->valid < tape->buffer_size) {
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actually_written = min_t(unsigned int,
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tape->buffer_size - tape->valid,
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count);
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if (copy_from_user(tape->cur, buf, actually_written))
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ret = -EFAULT;
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buf += actually_written;
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count -= actually_written;
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tape->cur += actually_written;
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tape->valid += actually_written;
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if (tape->valid == tape->buffer_size) {
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ssize_t retval;
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retval = idetape_add_chrdev_write_request(drive,
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tape->buffer_size);
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if (retval <= 0)
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return (retval);
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}
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}
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while (count >= tape->buffer_size) {
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ssize_t retval;
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if (copy_from_user(tape->cur, buf, tape->buffer_size))
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while (done < count) {
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size_t todo;
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/* flush if staging buffer is full */
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if (tape->valid == tape->buffer_size &&
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idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
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tape->buffer_size) <= 0)
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return rc;
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/* copy in */
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todo = min_t(size_t, count - done,
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tape->buffer_size - tape->valid);
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if (copy_from_user(tape->cur, buf + done, todo))
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ret = -EFAULT;
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buf += tape->buffer_size;
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count -= tape->buffer_size;
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retval = idetape_add_chrdev_write_request(drive,
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tape->buffer_size);
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actually_written += tape->buffer_size;
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if (retval <= 0)
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return (retval);
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tape->cur += todo;
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tape->valid += todo;
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done += todo;
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}
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if (count) {
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actually_written += count;
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if (copy_from_user(tape->cur, buf, count))
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ret = -EFAULT;
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tape->cur += count;
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tape->valid += count;
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}
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return ret ? ret : actually_written;
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return ret ? ret : done;
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}
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static int idetape_write_filemark(ide_drive_t *drive)
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