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ide-tape: simplify read/write functions
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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>
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Tejun Heo committed Apr 18, 2009
1 parent 6bb11dd commit 07bd968
Showing 1 changed file with 50 additions and 99 deletions.
149 changes: 50 additions & 99 deletions drivers/ide/ide-tape.c
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Original file line number Diff line number Diff line change
Expand Up @@ -953,14 +953,6 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
pc->flags |= PC_FLAG_WAIT_FOR_DSC;
}

/* Queue up a character device originated write request. */
static int idetape_add_chrdev_write_request(ide_drive_t *drive, int size)
{
debug_log(DBG_CHRDEV, "Enter %s\n", __func__);

return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, size);
}

static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
Expand All @@ -974,7 +966,7 @@ static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
size_t aligned = roundup(tape->valid, tape->blk_size);

memset(tape->cur, 0, aligned - tape->valid);
idetape_add_chrdev_write_request(drive, aligned);
idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, aligned);
kfree(tape->buf);
tape->buf = NULL;
}
Expand Down Expand Up @@ -1031,20 +1023,6 @@ static int idetape_init_rw(ide_drive_t *drive, int dir)
return 0;
}

/* called from idetape_chrdev_read() to service a chrdev read request. */
static int idetape_add_chrdev_read_request(ide_drive_t *drive, int size)
{
debug_log(DBG_PROCS, "Enter %s, %d bytes\n", __func__, size);

/* If we are at a filemark, return a read length of 0 */
if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
return 0;

idetape_init_rw(drive, IDETAPE_DIR_READ);

return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, size);
}

static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
{
idetape_tape_t *tape = drive->driver_data;
Expand Down Expand Up @@ -1184,8 +1162,9 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
{
struct ide_tape_obj *tape = file->private_data;
ide_drive_t *drive = tape->drive;
ssize_t bytes_read, temp, actually_read = 0, rc;
size_t done = 0;
ssize_t ret = 0;
int rc;

debug_log(DBG_CHRDEV, "Enter %s, count %Zd\n", __func__, count);

Expand All @@ -1195,60 +1174,51 @@ 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_rw(drive, IDETAPE_DIR_READ);
if (rc < 0)
return rc;
if (count == 0)
return (0);
if (tape->valid) {
actually_read = min_t(unsigned int, tape->valid, count);
if (copy_to_user(buf, tape->cur, actually_read))
ret = -EFAULT;
buf += actually_read;
count -= actually_read;
tape->cur += actually_read;
tape->valid -= actually_read;
}
while (count >= tape->buffer_size) {
bytes_read = idetape_add_chrdev_read_request(drive,
tape->buffer_size);
if (bytes_read <= 0)
goto finish;
if (copy_to_user(buf, tape->cur, bytes_read))
ret = -EFAULT;
buf += bytes_read;
count -= bytes_read;
actually_read += bytes_read;
}
if (count) {
bytes_read = idetape_add_chrdev_read_request(drive,
tape->buffer_size);
if (bytes_read <= 0)
goto finish;
temp = min((unsigned long)count, (unsigned long)bytes_read);
if (copy_to_user(buf, tape->cur, temp))

while (done < count) {
size_t todo;

/* refill if staging buffer is empty */
if (!tape->valid) {
/* If we are at a filemark, nothing more to read */
if (test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
break;
/* read */
if (idetape_queue_rw_tail(drive, REQ_IDETAPE_READ,
tape->buffer_size) <= 0)
break;
}

/* copy out */
todo = min_t(size_t, count - done, tape->valid);
if (copy_to_user(buf + done, tape->cur, todo))
ret = -EFAULT;
actually_read += temp;
tape->cur += temp;
tape->valid -= temp;

tape->cur += todo;
tape->valid -= todo;
done += todo;
}
finish:
if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {

if (!done && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
debug_log(DBG_SENSE, "%s: spacing over filemark\n", tape->name);

idetape_space_over_filemarks(drive, MTFSF, 1);
return 0;
}

return ret ? ret : actually_read;
return ret ? ret : done;
}

static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
struct ide_tape_obj *tape = file->private_data;
ide_drive_t *drive = tape->drive;
ssize_t actually_written = 0;
size_t done = 0;
ssize_t ret = 0;
int rc;

Expand All @@ -1262,47 +1232,28 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
rc = idetape_init_rw(drive, IDETAPE_DIR_WRITE);
if (rc < 0)
return rc;
if (count == 0)
return (0);
if (tape->valid < tape->buffer_size) {
actually_written = min_t(unsigned int,
tape->buffer_size - tape->valid,
count);
if (copy_from_user(tape->cur, buf, actually_written))
ret = -EFAULT;
buf += actually_written;
count -= actually_written;
tape->cur += actually_written;
tape->valid += actually_written;

if (tape->valid == tape->buffer_size) {
ssize_t retval;
retval = idetape_add_chrdev_write_request(drive,
tape->buffer_size);
if (retval <= 0)
return (retval);
}
}
while (count >= tape->buffer_size) {
ssize_t retval;
if (copy_from_user(tape->cur, buf, tape->buffer_size))
ret = -EFAULT;
buf += tape->buffer_size;
count -= tape->buffer_size;
retval = idetape_add_chrdev_write_request(drive,
tape->buffer_size);
actually_written += tape->buffer_size;
if (retval <= 0)
return (retval);
}
if (count) {
actually_written += count;
if (copy_from_user(tape->cur, buf, count))

while (done < count) {
size_t todo;

/* flush if staging buffer is full */
if (tape->valid == tape->buffer_size &&
idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
tape->buffer_size) <= 0)
return rc;

/* copy in */
todo = min_t(size_t, count - done,
tape->buffer_size - tape->valid);
if (copy_from_user(tape->cur, buf + done, todo))
ret = -EFAULT;
tape->cur += count;
tape->valid += count;

tape->cur += todo;
tape->valid += todo;
done += todo;
}
return ret ? ret : actually_written;

return ret ? ret : done;
}

static int idetape_write_filemark(ide_drive_t *drive)
Expand Down

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