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ide-tape: remove tape->merge_stage
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Get rid of the pipeline merge stage but retain the chrdev req caching
functionality by using a merge buffer tape->merge_bh which is flushed in chunks
of several blocks at a time. Also, remove last references to pipelining, e.g.
typedef idetape_stage_s.

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
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Borislav Petkov authored and Bartlomiej Zolnierkiewicz committed Apr 27, 2008
1 parent 01a63ae commit 077e3bd
Showing 1 changed file with 46 additions and 61 deletions.
107 changes: 46 additions & 61 deletions drivers/ide/ide-tape.c
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Original file line number Diff line number Diff line change
Expand Up @@ -215,13 +215,6 @@ enum {
IDETAPE_FLAG_MEDIUM_PRESENT = (1 << 6),
};

/* A pipeline stage. */
typedef struct idetape_stage_s {
struct request rq; /* The corresponding request */
struct idetape_bh *bh; /* The data buffers */
struct idetape_stage_s *next; /* Pointer to the next stage */
} idetape_stage_t;

/*
* Most of our global data which we need to save even as we leave the driver due
* to an interrupt or a timer event is stored in the struct defined below.
Expand Down Expand Up @@ -309,9 +302,11 @@ typedef struct ide_tape_obj {

/* Data buffer size chosen based on the tape's recommendation */
int buffer_size;
idetape_stage_t *merge_stage;
/* 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;
Expand Down Expand Up @@ -585,9 +580,9 @@ static void idetape_analyze_error(ide_drive_t *drive, u8 *sense)
}

/* Free data buffers completely. */
static void ide_tape_kfree_buffer(idetape_stage_t *stage)
static void ide_tape_kfree_buffer(idetape_tape_t *tape)
{
struct idetape_bh *prev_bh, *bh = stage->bh;
struct idetape_bh *prev_bh, *bh = tape->merge_bh;

while (bh) {
u32 size = bh->b_size;
Expand All @@ -605,7 +600,7 @@ static void ide_tape_kfree_buffer(idetape_stage_t *stage)
bh = bh->b_reqnext;
kfree(prev_bh);
}
kfree(stage);
kfree(tape->merge_bh);
}

static int idetape_end_request(ide_drive_t *drive, int uptodate, int nr_sects)
Expand Down Expand Up @@ -1299,22 +1294,16 @@ static ide_startstop_t idetape_do_request(ide_drive_t *drive,
* It returns a pointer to the newly allocated buffer, or NULL in case of
* failure.
*/
static idetape_stage_t *ide_tape_kmalloc_buffer(idetape_tape_t *tape, int full,
int clear)
static struct idetape_bh *ide_tape_kmalloc_buffer(idetape_tape_t *tape,
int full, int clear)
{
idetape_stage_t *stage;
struct idetape_bh *prev_bh, *bh;
struct idetape_bh *prev_bh, *bh, *merge_bh;
int pages = tape->pages_per_buffer;
unsigned int order, b_allocd;
char *b_data = NULL;

stage = kmalloc(sizeof(idetape_stage_t), GFP_KERNEL);
if (!stage)
return NULL;
stage->next = NULL;

stage->bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
bh = stage->bh;
merge_bh = kmalloc(sizeof(struct idetape_bh), GFP_KERNEL);
bh = merge_bh;
if (bh == NULL)
goto abort;

Expand Down Expand Up @@ -1374,9 +1363,9 @@ static idetape_stage_t *ide_tape_kmalloc_buffer(idetape_tape_t *tape, int full,
bh->b_size -= tape->excess_bh_size;
if (full)
atomic_sub(tape->excess_bh_size, &bh->b_count);
return stage;
return merge_bh;
abort:
ide_tape_kfree_buffer(stage);
ide_tape_kfree_buffer(tape);
return NULL;
}

Expand Down Expand Up @@ -1444,11 +1433,11 @@ static int idetape_copy_stage_to_user(idetape_tape_t *tape, char __user *buf,
return ret;
}

static void idetape_init_merge_stage(idetape_tape_t *tape)
static void idetape_init_merge_buffer(idetape_tape_t *tape)
{
struct idetape_bh *bh = tape->merge_stage->bh;
struct idetape_bh *bh = tape->merge_bh;
tape->bh = tape->merge_bh;

tape->bh = bh;
if (tape->chrdev_dir == IDETAPE_DIR_WRITE)
atomic_set(&bh->b_count, 0);
else {
Expand Down Expand Up @@ -1651,9 +1640,9 @@ static void __ide_tape_discard_merge_buffer(ide_drive_t *drive)

clear_bit(IDETAPE_FLAG_FILEMARK, &tape->flags);
tape->merge_bh_size = 0;
if (tape->merge_stage != NULL) {
ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
if (tape->merge_bh != NULL) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
}

tape->chrdev_dir = IDETAPE_DIR_NONE;
Expand Down Expand Up @@ -1725,8 +1714,8 @@ static int idetape_queue_rw_tail(ide_drive_t *drive, int cmd, int blocks,
if ((cmd & (REQ_IDETAPE_READ | REQ_IDETAPE_WRITE)) == 0)
return 0;

if (tape->merge_stage)
idetape_init_merge_stage(tape);
if (tape->merge_bh)
idetape_init_merge_buffer(tape);
if (rq.errors == IDETAPE_ERROR_GENERAL)
return -EIO;
return (tape->blk_size * (blocks-rq.current_nr_sectors));
Expand Down Expand Up @@ -1777,7 +1766,7 @@ static int idetape_add_chrdev_write_request(ide_drive_t *drive, int blocks)
debug_log(DBG_CHRDEV, "Enter %s\n", __func__);

return idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE,
blocks, tape->merge_stage->bh);
blocks, tape->merge_bh);
}

static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
Expand All @@ -1787,7 +1776,7 @@ static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
struct idetape_bh *bh;

if (tape->chrdev_dir != IDETAPE_DIR_WRITE) {
printk(KERN_ERR "ide-tape: bug: Trying to empty write pipeline,"
printk(KERN_ERR "ide-tape: bug: Trying to empty merge buffer"
" but we are not writing.\n");
return;
}
Expand Down Expand Up @@ -1827,9 +1816,9 @@ static void ide_tape_flush_merge_buffer(ide_drive_t *drive)
(void) idetape_add_chrdev_write_request(drive, blocks);
tape->merge_bh_size = 0;
}
if (tape->merge_stage != NULL) {
ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
if (tape->merge_bh != NULL) {
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
}
tape->chrdev_dir = IDETAPE_DIR_NONE;
}
Expand All @@ -1845,13 +1834,13 @@ static int idetape_init_read(ide_drive_t *drive)
ide_tape_flush_merge_buffer(drive);
idetape_flush_tape_buffers(drive);
}
if (tape->merge_stage || tape->merge_bh_size) {
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;
}
tape->merge_stage = ide_tape_kmalloc_buffer(tape, 0, 0);
if (!tape->merge_stage)
tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
if (!tape->merge_bh)
return -ENOMEM;
tape->chrdev_dir = IDETAPE_DIR_READ;

Expand All @@ -1864,10 +1853,10 @@ static int idetape_init_read(ide_drive_t *drive)
if (drive->dsc_overlap) {
bytes_read = idetape_queue_rw_tail(drive,
REQ_IDETAPE_READ, 0,
tape->merge_stage->bh);
tape->merge_bh);
if (bytes_read < 0) {
ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
tape->chrdev_dir = IDETAPE_DIR_NONE;
return bytes_read;
}
Expand All @@ -1891,7 +1880,7 @@ 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_stage->bh);
tape->merge_bh);
}

static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
Expand All @@ -1903,7 +1892,7 @@ static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
while (bcount) {
unsigned int count;

bh = tape->merge_stage->bh;
bh = tape->merge_bh;
count = min(tape->buffer_size, bcount);
bcount -= count;
blocks = count / tape->blk_size;
Expand All @@ -1915,7 +1904,7 @@ static void idetape_pad_zeros(ide_drive_t *drive, int bcount)
bh = bh->b_reqnext;
}
idetape_queue_rw_tail(drive, REQ_IDETAPE_WRITE, blocks,
tape->merge_stage->bh);
tape->merge_bh);
}
}

Expand Down Expand Up @@ -2000,10 +1989,6 @@ static int idetape_space_over_filemarks(ide_drive_t *drive, short mt_op,
ide_tape_discard_merge_buffer(drive, 0);
}

/*
* The filemark was not found in our internal pipeline; now we can issue
* the space command.
*/
switch (mt_op) {
case MTFSF:
case MTBSF:
Expand Down Expand Up @@ -2123,16 +2108,16 @@ 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_stage || tape->merge_bh_size) {
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;
}
tape->merge_stage = ide_tape_kmalloc_buffer(tape, 0, 0);
if (!tape->merge_stage)
tape->merge_bh = ide_tape_kmalloc_buffer(tape, 0, 0);
if (!tape->merge_bh)
return -ENOMEM;
tape->chrdev_dir = IDETAPE_DIR_WRITE;
idetape_init_merge_stage(tape);
idetape_init_merge_buffer(tape);

/*
* Issue a write 0 command to ensure that DSC handshake is
Expand All @@ -2143,10 +2128,10 @@ static ssize_t idetape_chrdev_write(struct file *file, const char __user *buf,
if (drive->dsc_overlap) {
ssize_t retval = idetape_queue_rw_tail(drive,
REQ_IDETAPE_WRITE, 0,
tape->merge_stage->bh);
tape->merge_bh);
if (retval < 0) {
ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
tape->chrdev_dir = IDETAPE_DIR_NONE;
return retval;
}
Expand Down Expand Up @@ -2508,12 +2493,12 @@ 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_stage = ide_tape_kmalloc_buffer(tape, 1, 0);
if (tape->merge_stage != NULL) {
tape->merge_bh = ide_tape_kmalloc_buffer(tape, 1, 0);
if (tape->merge_bh != NULL) {
idetape_pad_zeros(drive, tape->blk_size *
(tape->user_bs_factor - 1));
ide_tape_kfree_buffer(tape->merge_stage);
tape->merge_stage = NULL;
ide_tape_kfree_buffer(tape);
tape->merge_bh = NULL;
}
idetape_write_filemark(drive);
idetape_flush_tape_buffers(drive);
Expand Down

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