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Commit 963da55c authored by Tejun Heo's avatar Tejun Heo
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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 21d9c5d2

drivers/ide/ide-tape.c

+84 −221
Original line number Diff line number Diff line
@@ -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 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive, 
	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))

	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;