Commit 6cf3d545 authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe

ide-tape: kill idetape_bh

Impact: kill now unnecessary idetape_bh

With everything using standard mechanisms, there is no need for
idetape_bh anymore.  Kill it and use tape->buf, cur and valid to
describe data buffer instead.

Changes worth mentioning are...

* idetape_queue_rq_tail() now always queue tape->buf and and adjusts
  buffer state properly before completion.

* idetape_pad_zeros() clears the buffer only once.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent e998f30b
......@@ -131,12 +131,6 @@ enum {
IDETAPE_DIR_WRITE = (1 << 2),
};
struct idetape_bh {
u32 b_size;
atomic_t b_count;
char *b_data;
};
/* Tape door status */
#define DOOR_UNLOCKED 0
#define DOOR_LOCKED 1
......@@ -218,14 +212,12 @@ typedef struct ide_tape_obj {
/* Data buffer size chosen based on the tape's recommendation */
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;
/* Staging buffer of buffer_size bytes */
void *buf;
/* The read/write cursor */
void *cur;
/* The number of valid bytes in buf */
size_t valid;
/* Measures average tape speed */
unsigned long avg_time;
......@@ -351,15 +343,6 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
}
}
/* Free data buffers completely. */
static void ide_tape_kfree_buffer(idetape_tape_t *tape)
{
struct idetape_bh *bh = tape->merge_bh;
kfree(bh->b_data);
kfree(bh);
}
static void ide_tape_handle_dsc(ide_drive_t *);
static int ide_tape_callback(ide_drive_t *drive, int dsc)
......@@ -603,8 +586,7 @@ static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
struct ide_atapi_pc *pc, struct request *rq,
u8 opcode)
{
struct idetape_bh *bh = (struct idetape_bh *)rq->special;
unsigned int length = rq->current_nr_sectors;
unsigned int length = rq->nr_sectors;
ide_init_pc(pc);
put_unaligned(cpu_to_be32(length), (unsigned int *) &pc->c[1]);
......@@ -616,14 +598,11 @@ static void ide_tape_create_rw_cmd(idetape_tape_t *tape,
if (pc->req_xfer == tape->buffer_size)
pc->flags |= PC_FLAG_DMA_OK;
if (opcode == READ_6) {
if (opcode == READ_6)
pc->c[0] = READ_6;
atomic_set(&bh->b_count, 0);
} else if (opcode == WRITE_6) {
else if (opcode == WRITE_6) {
pc->c[0] = WRITE_6;
pc->flags |= PC_FLAG_WRITING;
pc->b_data = bh->b_data;
pc->b_count = atomic_read(&bh->b_count);
}
memcpy(rq->cmd, pc->c, 12);
......@@ -639,10 +618,8 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
struct ide_cmd cmd;
u8 stat;
debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu,"
" current_nr_sectors: %u\n",
(unsigned long long)rq->sector, rq->nr_sectors,
rq->current_nr_sectors);
debug_log(DBG_SENSE, "sector: %llu, nr_sectors: %lu\n"
(unsigned long long)rq->sector, rq->nr_sectors);
if (!(blk_special_request(rq) || blk_sense_request(rq))) {
/* We do not support buffer cache originated requests. */
......@@ -748,89 +725,6 @@ out:
return ide_tape_issue_pc(drive, &cmd, pc);
}
/*
* It returns a pointer to the newly allocated buffer, or NULL in case
* of failure.
*/
static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
int full)
{
struct idetape_bh *bh;
bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
if (!bh)
return NULL;
bh->b_data = kmalloc(tape->buffer_size, GFP_KERNEL);
if (!bh->b_data) {
kfree(bh);
return NULL;
}
bh->b_size = tape->buffer_size;
atomic_set(&bh->b_count, full ? bh->b_size : 0);
return bh;
}
static int idetape_copy_stage_from_user(idetape_tape_t *tape,
const char __user *buf, int n)
{
struct idetape_bh *bh = tape->bh;
int ret = 0;
if (n) {
if (bh == NULL || n > bh->b_size - atomic_read(&bh->b_count)) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return 1;
}
if (copy_from_user(bh->b_data + atomic_read(&bh->b_count), buf,
n))
ret = 1;
atomic_add(n, &bh->b_count);
if (atomic_read(&bh->b_count) == bh->b_size)
tape->bh = NULL;
}
return ret;
}
static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
int n)
{
struct idetape_bh *bh = tape->bh;
int ret = 0;
if (n) {
if (bh == NULL || n > tape->b_count) {
printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
__func__);
return 1;
}
if (copy_to_user(buf, tape->b_data, n))
ret = 1;
tape->b_data += n;
tape->b_count -= n;
if (!tape->b_count)
tape->bh = NULL;
}
return ret;
}
static void idetape_init_merge_buffer(idetape_tape_t *tape)
{
struct idetape_bh *bh = tape->merge_bh;
tape->bh = tape->merge_bh;
if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
atomic_set(&bh->b_count, 0);
else {
tape->b_data = bh->b_data;
tape->b_count = atomic_read(&bh->b_count);
}
}
/*
* Write a filemark if write_filemark=1. Flush the device buffers without
* writing a filemark otherwise.
......@@ -928,10 +822,10 @@ static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)
return;
clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags);
tape->merge_bh_size = 0;
if (tape->merge_bh != NULL) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
tape->valid = 0;
if (tape->buf != NULL) {
kfree(tape->buf);
tape->buf = NULL;
}
tape->chrdev_dir = IDETAPE_DIR_NONE;
......@@ -985,8 +879,7 @@ static void ide_tape_discard_merge_buffer(ide_drive_t *drive,
* Generate a read/write request for the block device interface and wait for it
* to be serviced.
*/
static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
struct idetape_bh *bh)
static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks)
{
idetape_tape_t *tape = drive->driver_data;
size_t size = blocks * tape->blk_size;
......@@ -1000,11 +893,10 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
rq->cmd_type = REQ_TYPE_SPECIAL;
rq->cmd[13] = cmd;
rq->rq_disk = tape->disk;
rq->special = (void *)bh;
rq->sector = tape->first_frame;
if (size) {
ret = blk_rq_map_kern(drive->queue, rq, bh->b_data, size,
ret = blk_rq_map_kern(drive->queue, rq, tape->buf, size,
__GFP_WAIT);
if (ret)
goto out_put;
......@@ -1012,17 +904,17 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
blk_execute_rq(drive->queue, tape->disk, rq, 0);
/* calculate the number of transferred bytes and update bh */
/* calculate the number of transferred bytes and update buffer state */
size -= rq->data_len;
tape->cur = tape->buf;
if (cmd == REQ_IDETAPE_READ)
atomic_add(size, &bh->b_count);
tape->valid = size;
else
tape->valid = 0;
ret = size;
if (rq->errors == IDE_DRV_ERROR_GENERAL)
ret = -EIO;
if (tape->merge_bh)
idetape_init_merge_buffer(tape);
out_put:
blk_put_request(rq);
return ret;
......@@ -1064,49 +956,33 @@ static void idetape_create_space_cmd(struct ide_atapi_pc *pc, int count, u8 cmd)
/* 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;
debug_log(DBG_CHRDEV, "Enter %s\n", __func__);
return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
blocks, tape->merge_bh);
return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks);
}
static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
{
idetape_tape_t *tape = drive->driver_data;
int blocks;
struct idetape_bh *bh;
if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
" but we are not writing.\n");
return;
}
if (tape->merge_bh_size > tape->buffer_size) {
printk(KERN_ERR "ide-tape: bug: merge_buffer too big\n");
tape->merge_bh_size = tape->buffer_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 = tape->blk_size -
tape->merge_bh_size % tape->blk_size;
if (tape->buf) {
blocks = tape->valid / tape->blk_size;
if (tape->valid % tape->blk_size) {
blocks++;
bh = tape->bh;
if (bh) {
memset(bh->b_data + atomic_read(&bh->b_count),
0, i);
atomic_add(i, &bh->b_count);
} else
printk(KERN_INFO "ide-tape: bug, bh NULL\n");
memset(tape->buf + tape->valid, 0,
tape->blk_size - tape->valid % tape->blk_size);
}
(void) idetape_add_chrdev_write_request(drive, blocks);
tape->merge_bh_size = 0;
}
if (tape->merge_bh != NULL) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
if (tape->buf != NULL) {
kfree(tape->buf);
tape->buf = NULL;
}
tape->chrdev_dir = IDETAPE_DIR_NONE;
}
......@@ -1122,15 +998,15 @@ static int idetape_init_read(ide_drive_t *drive)
ide_tape_flush_merge_buffer(drive);
idetape_flush_tape_buffers(drive);
}
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;
if (tape->buf || tape->valid) {
printk(KERN_ERR "ide-tape: valid should be 0 now\n");
tape->valid = 0;
}
tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0);
if (!tape->merge_bh)
tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL);
if (!tape->buf)
return -ENOMEM;
tape->chrdev_dir = IDETAPE_DIR_READ;
tape->cur = tape->buf;
/*
* Issue a read 0 command to ensure that DSC handshake is
......@@ -1140,11 +1016,10 @@ static int idetape_init_read(ide_drive_t *drive)
*/
if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
bytes_read = idetape_queue_rw_tail(drive,
REQ_IDETAPE_READ, 0,
tape->merge_bh);
REQ_IDETAPE_READ, 0);
if (bytes_read < 0) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
kfree(tape->buf);
tape->buf = NULL;
tape->chrdev_dir = IDETAPE_DIR_NONE;
return bytes_read;
}
......@@ -1157,8 +1032,6 @@ static int idetape_init_read(ide_drive_t *drive)
/* 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;
debug_log(DBG_PROCS, "Enter %s, %d blocks\n", __func__, blocks);
/* If we are at a filemark, return a read length of 0 */
......@@ -1167,27 +1040,21 @@ 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_bh);
return idetape_queue_rw_tail(drive, REQ_IDETAPE_READ, blocks);
}
static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
{
idetape_tape_t *tape = drive->driver_data;
struct idetape_bh *bh = tape->merge_bh;
int blocks;
memset(tape->buf, 0, tape->buffer_size);
while (bcount) {
unsigned int count;
unsigned int count = min(tape->buffer_size, bcount);
count = min(tape->buffer_size, bcount);
idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
count / tape->blk_size);
bcount -= count;
blocks = count / tape->blk_size;
atomic_set(&bh->b_count, count);
memset(bh->b_data, 0, atomic_read(&bh->b_count));
idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
tape->merge_bh);
}
}
......@@ -1267,7 +1134,7 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
}
if (tape->chrdev_dir == IDETAPE_DIR_READ) {
tape->merge_bh_size = 0;
tape->valid = 0;
if (test_and_clear_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags))
++count;
ide_tape_discard_merge_buffer(drive, 0);
......@@ -1333,20 +1200,20 @@ static ssize_t idetape_chrdev_read(struct file *file, char __user *buf,
return rc;
if (count == 0)
return (0);
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, actually_read))
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;
tape->merge_bh_size -= 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, ctl);
if (bytes_read <= 0)
goto finish;
if (idetape_copy_stage_to_user(tape, buf, bytes_read))
if (copy_to_user(buf, tape->cur, bytes_read))
ret = -EFAULT;
buf += bytes_read;
count -= bytes_read;
......@@ -1357,10 +1224,11 @@ 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, temp))
if (copy_to_user(buf, tape->cur, temp))
ret = -EFAULT;
actually_read += temp;
tape->merge_bh_size = bytes_read-temp;
tape->cur += temp;
tape->valid -= temp;
}
finish:
if (!actually_read && test_bit(IDE_AFLAG_FILEMARK, &drive->atapi_flags)) {
......@@ -1392,16 +1260,15 @@ 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_bh || tape->merge_bh_size) {
printk(KERN_ERR "ide-tape: merge_bh_size "
"should be 0 now\n");
tape->merge_bh_size = 0;
if (tape->buf || tape->valid) {
printk(KERN_ERR "ide-tape: valid should be 0 now\n");
tape->valid = 0;
}
tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0);
if (!tape->merge_bh)
tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL);
if (!tape->buf)
return -ENOMEM;
tape->chrdev_dir = IDETAPE_DIR_WRITE;
idetape_init_merge_buffer(tape);
tape->cur = tape->buf;
/*
* Issue a write 0 command to ensure that DSC handshake is
......@@ -1411,11 +1278,10 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
*/
if (drive->dev_flags & IDE_DFLAG_DSC_OVERLAP) {
ssize_t retval = idetape_queue_rw_tail(drive,
REQ_IDETAPE_WRITE, 0,
tape->merge_bh);
REQ_IDETAPE_WRITE, 0);
if (retval < 0) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
kfree(tape->buf);
tape->buf = NULL;
tape->chrdev_dir = IDETAPE_DIR_NONE;
return retval;
}
......@@ -1423,23 +1289,19 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
}
if (count == 0)
return (0);
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_bh_size = 0;
}
actually_written = min((unsigned int)
(tape->buffer_size - tape->merge_bh_size),
(unsigned int)count);
if (idetape_copy_stage_from_user(tape, buf, actually_written))
ret = -EFAULT;
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;
tape->merge_bh_size += actually_written;
count -= actually_written;
tape->cur += actually_written;
tape->valid += actually_written;
if (tape->merge_bh_size == tape->buffer_size) {
if (tape->valid == tape->buffer_size) {
ssize_t retval;
tape->merge_bh_size = 0;
retval = idetape_add_chrdev_write_request(drive, ctl);
if (retval <= 0)
return (retval);
......@@ -1447,7 +1309,7 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
}
while (count >= tape->buffer_size) {
ssize_t retval;
if (idetape_copy_stage_from_user(tape, buf, tape->buffer_size))
if (copy_from_user(tape->cur, buf, tape->buffer_size))
ret = -EFAULT;
buf += tape->buffer_size;
count -= tape->buffer_size;
......@@ -1458,9 +1320,10 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
}
if (count) {
actually_written += count;
if (idetape_copy_stage_from_user(tape, buf, count))
if (copy_from_user(tape->cur, buf, count))
ret = -EFAULT;
tape->merge_bh_size += count;
tape->cur += count;
tape->valid += count;
}
return ret ? ret : actually_written;
}
......@@ -1623,7 +1486,7 @@ static int idetape_chrdev_ioctl(struct inode *inode, struct file *file,
idetape_flush_tape_buffers(drive);
}
if (cmd == MTIOCGET || cmd == MTIOCPOS) {
block_offset = tape->merge_bh_size /
block_offset = tape->valid /
(tape->blk_size * tape->user_bs_factor);
position = idetape_read_position(drive);
if (position < 0)
......@@ -1771,12 +1634,12 @@ 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_bh = ide_tape_kmalloc_buffer(tape, 1);
if (tape->merge_bh != NULL) {
tape->buf = kmalloc(tape->buffer_size, GFP_KERNEL);
if (tape->buf != NULL) {
idetape_pad_zeros(drive, tape->blk_size *
(tape->user_bs_factor - 1));
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
kfree(tape->buf);
tape->buf = NULL;
}
idetape_write_filemark(drive);
idetape_flush_tape_buffers(drive);
......@@ -2042,7 +1905,7 @@ static void ide_tape_release(struct device *dev)
ide_drive_t *drive = tape->drive;
struct gendisk *g = tape->disk;
BUG_ON(tape->merge_bh_size);
BUG_ON(tape->valid);
drive->dev_flags &= ~IDE_DFLAG_DSC_OVERLAP;
drive->driver_data = NULL;
......
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