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Commit f179b6ce authored by Kai Mäkisara's avatar Kai Mäkisara Committed by Linus Torvalds
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[PATCH] 2.5.22 SCSI tape buffering changes 

This contains the following changes to the SCSI tape driver:

- one buffer is used for each tape (no buffer pool)
- buffers allocated when needed and freed when device closed
- common code from read and write moved to a function
- default maximum number of scatter/gather segments increased to 64
- tape status set to "no tape" after succesful unload
parent d9083ea2
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Showing with 152 additions and 338 deletions
drivers/scsi/README.st
View file @ f179b6ce
......@@ -2,7 +2,7 @@ This file contains brief information about the SCSI tape driver.
The driver is currently maintained by Kai M{kisara (email
Kai.Makisara@metla.fi)
Last modified: Tue Jan 22 21:08:57 2002 by makisara
Last modified: Tue Jun 18 18:13:50 2002 by makisara
BASICS
......@@ -105,15 +105,19 @@ The default is BSD semantics.
BUFFERING
The driver uses tape buffers allocated either at system initialization
or at run-time when needed. One buffer is used for each open tape
device. The size of the buffers is selectable at compile and/or boot
time. The buffers are used to store the data being transferred to/from
the SCSI adapter. The following buffering options are selectable at
compile time and/or at run time (via ioctl):
The driver uses tape buffers allocated at run-time when needed and it
is freed when the device file is closed. One buffer is used for each
open tape device.
The size of the buffers is always at least one tape block. In fixed
block mode, the minimum buffer size is defined (in 1024 byte units) by
ST_FIXED_BUFFER_BLOCKS. With small block size this allows buffering of
several blocks and using one SCSI read or write to transfer all of the
blocks. Buffering of data across write calls in fixed block mode is
allowed if ST_BUFFER_WRITES is non-zero. Buffer allocation uses chunks of
memory having sizes 2^n * (page size). Because of this the actual
buffer size may be larger than the minimum allowable buffer size.
Buffering of data across write calls in fixed block mode (define
ST_BUFFER_WRITES).
Asynchronous writing. Writing the buffer contents to the tape is
started and the write call returns immediately. The status is checked
......@@ -128,30 +132,6 @@ attempted even if the user does not want to get all of the data at
this read command. Should be disabled for those drives that don't like
a filemark to truncate a read request or that don't like backspacing.
The buffer size is defined (in 1024 byte units) by ST_BUFFER_BLOCKS or
at boot time. If this size is not large enough, the driver tries to
temporarily enlarge the buffer. Buffer allocation uses chunks of
memory having sizes 2^n * (page size). Because of this the actual
buffer size may be larger than the buffer size specified with
ST_BUFFER_BLOCKS.
A small number of buffers are allocated at driver initialisation. The
maximum number of these buffers is defined by ST_MAX_BUFFERS. The
maximum can be changed with kernel or module startup options. One
buffer is allocated for each drive detected when the driver is
initialized up to the maximum.
The driver tries to allocate new buffers at run-time if
necessary. These buffers are freed after use. If the maximum number of
initial buffers is set to zero, all buffer allocation is done at
run-time. The advantage of run-time allocation is that memory is not
wasted for buffers not being used. The disadvantage is that there may
not be memory available at the time when a buffer is needed for the
first time (once a buffer is allocated, it is not released). This risk
should not be big if the tape drive is connected to a PCI adapter that
supports scatter/gather (the allocation is not limited to "DMA memory"
and the buffer can be composed of several fragments).
The threshold for triggering asynchronous write in fixed block mode
is defined by ST_WRITE_THRESHOLD. This may be optimized for each
use pattern. The default triggers asynchronous write after three
......
drivers/scsi/st.c
View file @ f179b6ce
......@@ -12,13 +12,13 @@
Copyright 1992 - 2002 Kai Makisara
email Kai.Makisara@metla.fi
Last modified: Tue Feb 5 21:25:55 2002 by makisara
Last modified: Sat Jun 15 13:01:56 2002 by makisara
Some small formal changes - aeb, 950809
Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
*/
static char *verstr = "20020205";
static char *verstr = "20020615";
#include <linux/module.h>
......@@ -69,7 +69,6 @@ static char *verstr = "20020205";
static int buffer_kbs;
static int write_threshold_kbs;
static int max_buffers = (-1);
static int max_sg_segs;
MODULE_AUTHOR("Kai Makisara");
......@@ -80,8 +79,6 @@ MODULE_PARM(buffer_kbs, "i");
MODULE_PARM_DESC(buffer_kbs, "Default driver buffer size (KB; 32)");
MODULE_PARM(write_threshold_kbs, "i");
MODULE_PARM_DESC(write_threshold_kbs, "Asynchronous write threshold (KB; 30)");
MODULE_PARM(max_buffers, "i");
MODULE_PARM_DESC(max_buffers, "Maximum number of buffer allocated at initialisation (4)");
MODULE_PARM(max_sg_segs, "i");
MODULE_PARM_DESC(max_sg_segs, "Maximum number of scatter/gather segments to use (32)");
......@@ -96,9 +93,6 @@ static struct st_dev_parm {
{
"write_threshold_kbs", &write_threshold_kbs
},
{
"max_buffers", &max_buffers
},
{
"max_sg_segs", &max_sg_segs
}
......@@ -108,12 +102,12 @@ static struct st_dev_parm {
/* The default definitions have been moved to st_options.h */
#define ST_BUFFER_SIZE (ST_BUFFER_BLOCKS * ST_KILOBYTE)
#define ST_FIXED_BUFFER_SIZE (ST_FIXED_BUFFER_BLOCKS * ST_KILOBYTE)
#define ST_WRITE_THRESHOLD (ST_WRITE_THRESHOLD_BLOCKS * ST_KILOBYTE)
/* The buffer size should fit into the 24 bits for length in the
6-byte SCSI read and write commands. */
#if ST_BUFFER_SIZE >= (2 << 24 - 1)
#if ST_FIXED_BUFFER_SIZE >= (2 << 24 - 1)
#error "Buffer size should not exceed (2 << 24 - 1) bytes!"
#endif
......@@ -121,7 +115,7 @@ DEB( static int debugging = DEBUG; )
#define MAX_RETRIES 0
#define MAX_WRITE_RETRIES 0
#define MAX_READY_RETRIES 5
#define MAX_READY_RETRIES 0
#define NO_TAPE NOT_READY
#define ST_TIMEOUT (900 * HZ)
......@@ -137,18 +131,15 @@ DEB( static int debugging = DEBUG; )
#define ST_DEV_ARR_LUMP 6
static rwlock_t st_dev_arr_lock = RW_LOCK_UNLOCKED;
static int st_nbr_buffers;
static ST_buffer **st_buffers = NULL;
static int st_buffer_size = ST_BUFFER_SIZE;
static int st_fixed_buffer_size = ST_FIXED_BUFFER_SIZE;
static int st_write_threshold = ST_WRITE_THRESHOLD;
static int st_max_buffers = ST_MAX_BUFFERS;
static int st_max_sg_segs = ST_MAX_SG;
static Scsi_Tape **scsi_tapes = NULL;
static int modes_defined;
static ST_buffer *new_tape_buffer(int, int, int);
static ST_buffer *new_tape_buffer(int, int);
static int enlarge_buffer(ST_buffer *, int, int);
static void normalize_buffer(ST_buffer *);
static int append_to_buffer(const char *, ST_buffer *, int);
......@@ -914,8 +905,7 @@ static int check_tape(Scsi_Tape *STp, struct file *filp)
module count. */
static int st_open(struct inode *inode, struct file *filp)
{
int i, need_dma_buffer;
int retval = (-EIO);
int i, retval = (-EIO);
Scsi_Tape *STp;
ST_partstat *STps;
int dev = TAPE_NR(inode->i_rdev);
......@@ -945,38 +935,15 @@ static int st_open(struct inode *inode, struct file *filp)
goto err_out;
}
/* Allocate a buffer for this user */
need_dma_buffer = STp->restr_dma;
write_lock(&st_dev_arr_lock);
for (i = 0; i < st_nbr_buffers; i++)
if (!st_buffers[i]->in_use &&
(!need_dma_buffer || st_buffers[i]->dma)) {
STp->buffer = st_buffers[i];
(STp->buffer)->in_use = 1;
break;
}
write_unlock(&st_dev_arr_lock);
if (i >= st_nbr_buffers) {
STp->buffer = new_tape_buffer(FALSE, need_dma_buffer, TRUE);
if (STp->buffer == NULL) {
/* See that we have at least a one page buffer available */
if (!enlarge_buffer(STp->buffer, PAGE_SIZE, STp->restr_dma)) {
printk(KERN_WARNING "st%d: Can't allocate tape buffer.\n", dev);
retval = (-EBUSY);
retval = (-EOVERFLOW);
goto err_out;
}
}
(STp->buffer)->writing = 0;
(STp->buffer)->syscall_result = 0;
(STp->buffer)->use_sg = STp->device->host->sg_tablesize;
/* Compute the usable buffer size for this SCSI adapter */
if (!(STp->buffer)->use_sg)
(STp->buffer)->buffer_size = (STp->buffer)->sg[0].length;
else {
for (i = 0, (STp->buffer)->buffer_size = 0; i < (STp->buffer)->use_sg &&
i < (STp->buffer)->sg_segs; i++)
(STp->buffer)->buffer_size += (STp->buffer)->sg[i].length;
}
STp->write_prot = ((filp->f_flags & O_ACCMODE) == O_RDONLY);
......@@ -999,10 +966,7 @@ static int st_open(struct inode *inode, struct file *filp)
return 0;
err_out:
if (STp->buffer != NULL) {
(STp->buffer)->in_use = 0;
STp->buffer = NULL;
}
normalize_buffer(STp->buffer);
STp->in_use = 0;
STp->device->access_count--;
if (STp->device->host->hostt->module)
......@@ -1149,16 +1113,8 @@ static int st_release(struct inode *inode, struct file *filp)
if (STp->door_locked == ST_LOCKED_AUTO)
st_int_ioctl(STp, MTUNLOCK, 0);
if (STp->buffer != NULL) {
normalize_buffer(STp->buffer);
write_lock(&st_dev_arr_lock);
(STp->buffer)->in_use = 0;
STp->buffer = NULL;
}
else {
write_lock(&st_dev_arr_lock);
}
STp->in_use = 0;
write_unlock(&st_dev_arr_lock);
STp->device->access_count--;
......@@ -1168,31 +1124,11 @@ static int st_release(struct inode *inode, struct file *filp)
return result;
}
/* Write command */
static ssize_t
st_write(struct file *filp, const char *buf, size_t count, loff_t * ppos)
/* The checks common to both reading and writing */
static ssize_t rw_checks(Scsi_Tape *STp, struct file *filp, size_t count, loff_t *ppos)
{
struct inode *inode = filp->f_dentry->d_inode;
ssize_t total;
ssize_t i, do_count, blks, transfer;
int bufsize;
ssize_t retval = 0;
int write_threshold;
int doing_write = 0;
unsigned char cmd[MAX_COMMAND_SIZE];
const char *b_point;
Scsi_Request *SRpnt = NULL;
Scsi_Tape *STp;
ST_mode *STm;
ST_partstat *STps;
int dev = TAPE_NR(inode->i_rdev);
read_lock(&st_dev_arr_lock);
STp = scsi_tapes[dev];
read_unlock(&st_dev_arr_lock);
if (down_interruptible(&STp->lock))
return -ERESTARTSYS;
/*
* If we are in the middle of error recovery, don't let anyone
......@@ -1219,13 +1155,11 @@ static ssize_t
goto out;
}
STm = &(STp->modes[STp->current_mode]);
if (!STm->defined) {
if (! STp->modes[STp->current_mode].defined) {
retval = (-ENXIO);
goto out;
}
if (count == 0)
goto out;
/*
* If there was a bus reset, block further access
......@@ -1236,30 +1170,20 @@ static ssize_t
goto out;
}
if (count == 0)
goto out;
DEB(
if (!STp->in_use) {
int dev = TAPE_NR(filp->f_dentry->d_inode->i_rdev);
printk(ST_DEB_MSG "st%d: Incorrect device.\n", dev);
retval = (-EIO);
goto out;
} ) /* end DEB */
/* Write must be integral number of blocks */
if (STp->block_size != 0 && (count % STp->block_size) != 0) {
printk(KERN_WARNING "st%d: Write not multiple of tape block size.\n",
dev);
retval = (-EINVAL);
goto out;
}
if (STp->can_partitions &&
(retval = update_partition(STp)) < 0)
goto out;
STps = &(STp->ps[STp->partition]);
if (STp->write_prot) {
retval = (-EACCES);
goto out;
}
if (STp->block_size == 0) {
if (STp->max_block > 0 &&
......@@ -1273,19 +1197,73 @@ static ssize_t
goto out;
}
}
if ((STp->buffer)->buffer_blocks < 1) {
/* Fixed block mode with too small buffer */
if (!enlarge_buffer(STp->buffer, STp->block_size, STp->restr_dma)) {
else {
/* Fixed block mode with too small buffer? */
bufsize = STp->block_size > st_fixed_buffer_size ?
STp->block_size : st_fixed_buffer_size;
if ((STp->buffer)->buffer_size < bufsize &&
!enlarge_buffer(STp->buffer, bufsize, STp->restr_dma)) {
retval = (-EOVERFLOW);
goto out;
}
(STp->buffer)->buffer_blocks = 1;
(STp->buffer)->buffer_blocks = bufsize / STp->block_size;
}
if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
!st_int_ioctl(STp, MTLOCK, 0))
STp->door_locked = ST_LOCKED_AUTO;
out:
return retval;
}
/* Write command */
static ssize_t
st_write(struct file *filp, const char *buf, size_t count, loff_t * ppos)
{
struct inode *inode = filp->f_dentry->d_inode;
ssize_t total;
ssize_t i, do_count, blks, transfer;
ssize_t retval;
int write_threshold;
int doing_write = 0;
unsigned char cmd[MAX_COMMAND_SIZE];
const char *b_point;
Scsi_Request *SRpnt = NULL;
Scsi_Tape *STp;
ST_mode *STm;
ST_partstat *STps;
int dev = TAPE_NR(inode->i_rdev);
read_lock(&st_dev_arr_lock);
STp = scsi_tapes[dev];
read_unlock(&st_dev_arr_lock);
if (down_interruptible(&STp->lock))
return -ERESTARTSYS;
retval = rw_checks(STp, filp, count, ppos);
if (retval || count == 0)
goto out;
/* Write must be integral number of blocks */
if (STp->block_size != 0 && (count % STp->block_size) != 0) {
printk(KERN_WARNING "st%d: Write not multiple of tape block size.\n",
dev);
retval = (-EINVAL);
goto out;
}
STm = &(STp->modes[STp->current_mode]);
STps = &(STp->ps[STp->partition]);
if (STp->write_prot) {
retval = (-EACCES);
goto out;
}
if (STps->rw == ST_READING) {
retval = flush_buffer(STp, 0);
if (retval)
......@@ -1718,77 +1696,17 @@ static ssize_t
if (down_interruptible(&STp->lock))
return -ERESTARTSYS;
/*
* If we are in the middle of error recovery, don't let anyone
* else try and use this device. Also, if error recovery fails, it
* may try and take the device offline, in which case all further
* access to the device is prohibited.
*/
if (!scsi_block_when_processing_errors(STp->device)) {
retval = (-ENXIO);
retval = rw_checks(STp, filp, count, ppos);
if (retval || count == 0)
goto out;
}
if (ppos != &filp->f_pos) {
/* "A request was outside the capabilities of the device." */
retval = (-ENXIO);
goto out;
}
if (STp->ready != ST_READY) {
if (STp->ready == ST_NO_TAPE)
retval = (-ENOMEDIUM);
else
retval = (-EIO);
goto out;
}
STm = &(STp->modes[STp->current_mode]);
if (!STm->defined) {
retval = (-ENXIO);
goto out;
}
DEB(
if (!STp->in_use) {
printk(ST_DEB_MSG "st%d: Incorrect device.\n", dev);
retval = (-EIO);
goto out;
} ) /* end DEB */
if (STp->can_partitions &&
(retval = update_partition(STp)) < 0)
goto out;
if (STp->block_size == 0) {
if (STp->max_block > 0 &&
(count < STp->min_block || count > STp->max_block)) {
retval = (-EINVAL);
goto out;
}
if (count > (STp->buffer)->buffer_size &&
!enlarge_buffer(STp->buffer, count, STp->restr_dma)) {
retval = (-EOVERFLOW);
goto out;
}
}
if ((STp->buffer)->buffer_blocks < 1) {
/* Fixed block mode with too small buffer */
if (!enlarge_buffer(STp->buffer, STp->block_size, STp->restr_dma)) {
retval = (-EOVERFLOW);
goto out;
}
(STp->buffer)->buffer_blocks = 1;
}
if (!(STm->do_read_ahead) && STp->block_size != 0 &&
(count % STp->block_size) != 0) {
retval = (-EINVAL); /* Read must be integral number of blocks */
goto out;
}
if (STp->do_auto_lock && STp->door_locked == ST_UNLOCKED &&
!st_int_ioctl(STp, MTLOCK, 0))
STp->door_locked = ST_LOCKED_AUTO;
STps = &(STp->ps[STp->partition]);
if (STps->rw == ST_WRITING) {
retval = flush_buffer(STp, 0);
......@@ -1986,7 +1904,7 @@ static int st_set_options(Scsi_Tape *STp, long options)
st_log_options(STp, STm, dev);
} else if (code == MT_ST_WRITE_THRESHOLD) {
value = (options & ~MT_ST_OPTIONS) * ST_KILOBYTE;
if (value < 1 || value > st_buffer_size) {
if (value < 1 || value > st_fixed_buffer_size) {
printk(KERN_WARNING
"st%d: Write threshold %d too small or too large.\n",
dev, value);
......@@ -2289,8 +2207,10 @@ static int do_load_unload(Scsi_Tape *STp, struct file *filp, int load_code)
if (!retval) { /* SCSI command successful */
if (!load_code)
if (!load_code) {
STp->rew_at_close = 0;
STp->ready = ST_NO_TAPE;
}
else {
STp->rew_at_close = STp->autorew_dev;
retval = check_tape(STp, filp);
......@@ -2619,10 +2539,14 @@ static int st_int_ioctl(Scsi_Tape *STp, unsigned int cmd_in, unsigned long arg)
ioctl_result = st_int_ioctl(STp, MTBSF, 1);
if (cmd_in == MTSETBLK || cmd_in == SET_DENS_AND_BLK) {
int old_block_size = STp->block_size;
STp->block_size = arg & MT_ST_BLKSIZE_MASK;
if (STp->block_size != 0)
if (STp->block_size != 0) {
if (old_block_size == 0)
normalize_buffer(STp->buffer);
(STp->buffer)->buffer_blocks =
(STp->buffer)->buffer_size / STp->block_size;
}
(STp->buffer)->buffer_bytes = (STp->buffer)->read_pointer = 0;
if (cmd_in == SET_DENS_AND_BLK)
STp->density = arg >> MT_ST_DENSITY_SHIFT;
......@@ -3372,18 +3296,11 @@ static int st_ioctl(struct inode *inode, struct file *file,
/* Try to allocate a new tape buffer. Calling function must not hold
dev_arr_lock. */
static ST_buffer *
new_tape_buffer(int from_initialization, int need_dma, int in_use)
new_tape_buffer(int from_initialization, int need_dma)
{
int i, priority, b_size, order, got = 0, segs = 0;
int i, priority, got = 0, segs = 0;
ST_buffer *tb;
read_lock(&st_dev_arr_lock);
if (st_nbr_buffers >= st_template.dev_max) {
read_unlock(&st_dev_arr_lock);
return NULL; /* Should never happen */
}
read_unlock(&st_dev_arr_lock);
if (from_initialization)
priority = GFP_ATOMIC;
else
......@@ -3391,85 +3308,19 @@ static ST_buffer *
i = sizeof(ST_buffer) + (st_max_sg_segs - 1) * sizeof(struct scatterlist);
tb = kmalloc(i, priority);
if (tb) {
if (need_dma)
priority |= GFP_DMA;
/* Try to allocate the first segment up to ST_FIRST_ORDER and the
others big enough to reach the goal */
for (b_size = PAGE_SIZE, order=0;
b_size < st_buffer_size && order < ST_FIRST_ORDER;
order++, b_size *= 2)
;
for ( ; b_size >= PAGE_SIZE; order--, b_size /= 2) {
tb->sg[0].page = alloc_pages(priority, order);
tb->sg[0].offset = 0;
if (tb->sg[0].page != NULL) {
tb->sg[0].length = b_size;
break;
}
}
if (tb->sg[segs].page == NULL) {
kfree(tb);
tb = NULL;
} else { /* Got something, continue */
for (b_size = PAGE_SIZE, order=0;
st_buffer_size >
tb->sg[0].length + (ST_FIRST_SG - 1) * b_size;
order++, b_size *= 2)
;
for (segs = 1, got = tb->sg[0].length;
got < st_buffer_size && segs < ST_FIRST_SG;) {
tb->sg[segs].page = alloc_pages(priority, order);
tb->sg[segs].offset = 0;
if (tb->sg[segs].page == NULL) {
if (st_buffer_size - got <=
(ST_FIRST_SG - segs) * b_size / 2) {
b_size /= 2; /* Large enough for the
rest of the buffers */
order--;
continue;
}
tb->sg_segs = segs;
tb->orig_sg_segs = 0;
DEB(tb->buffer_size = got);
normalize_buffer(tb);
kfree(tb);
tb = NULL;
break;
}
tb->sg[segs].length = b_size;
got += b_size;
segs++;
}
}
}
if (!tb) {
printk(KERN_NOTICE "st: Can't allocate new tape buffer (nbr %d).\n",
st_nbr_buffers);
printk(KERN_NOTICE "st: Can't allocate new tape buffer.\n");
return NULL;
}
tb->sg_segs = tb->orig_sg_segs = segs;
if (segs > 0)
tb->b_data = page_address(tb->sg[0].page);
DEBC(printk(ST_DEB_MSG
"st: Allocated tape buffer %d (%d bytes, %d segments, dma: %d, a: %p).\n",
st_nbr_buffers, got, tb->sg_segs, need_dma, tb->b_data);
printk(ST_DEB_MSG
"st: segment sizes: first %d, last %d bytes.\n",
tb->sg[0].length, tb->sg[segs - 1].length);
)
tb->in_use = in_use;
tb->in_use = TRUE;
tb->dma = need_dma;
tb->buffer_size = got;
tb->writing = 0;
write_lock(&st_dev_arr_lock);
st_buffers[st_nbr_buffers++] = tb;
write_unlock(&st_dev_arr_lock);
return tb;
}
......@@ -3479,6 +3330,9 @@ static int enlarge_buffer(ST_buffer * STbuffer, int new_size, int need_dma)
{
int segs, nbr, max_segs, b_size, priority, order, got;
if (new_size <= STbuffer->buffer_size)
return TRUE;
normalize_buffer(STbuffer);
max_segs = STbuffer->use_sg;
......@@ -3492,13 +3346,14 @@ static int enlarge_buffer(ST_buffer * STbuffer, int new_size, int need_dma)
if (need_dma)
priority |= GFP_DMA;
for (b_size = PAGE_SIZE, order=0;
b_size * nbr < new_size - STbuffer->buffer_size;
b_size < new_size - STbuffer->buffer_size;
order++, b_size *= 2)
; /* empty */
for (segs = STbuffer->sg_segs, got = STbuffer->buffer_size;
segs < max_segs && got < new_size;) {
STbuffer->sg[segs].page = alloc_pages(priority, order);
/* printk("st: allocated %x, order %d\n", STbuffer->sg[segs].page, order); */
STbuffer->sg[segs].offset = 0;
if (STbuffer->sg[segs].page == NULL) {
if (new_size - got <= (max_segs - segs) * b_size / 2) {
......@@ -3518,9 +3373,10 @@ static int enlarge_buffer(ST_buffer * STbuffer, int new_size, int need_dma)
STbuffer->buffer_size = got;
segs++;
}
STbuffer->b_data = page_address(STbuffer->sg[0].page);
DEBC(printk(ST_DEB_MSG
"st: Succeeded to enlarge buffer to %d bytes (segs %d->%d, %d).\n",
got, STbuffer->orig_sg_segs, STbuffer->sg_segs, b_size));
"st: Succeeded to enlarge buffer at %p to %d bytes (segs %d->%d, %d).\n",
STbuffer, got, STbuffer->orig_sg_segs, STbuffer->sg_segs, b_size));
return TRUE;
}
......@@ -3535,14 +3391,14 @@ static void normalize_buffer(ST_buffer * STbuffer)
for (b_size=PAGE_SIZE, order=0; b_size < STbuffer->sg[i].length;
order++, b_size *= 2)
; /* empty */
/* printk("st: freeing %x, order %d\n", STbuffer->sg[i].page, order); */
__free_pages(STbuffer->sg[i].page, order);
STbuffer->buffer_size -= STbuffer->sg[i].length;
}
DEB(
if (debugging && STbuffer->orig_sg_segs < STbuffer->sg_segs)
printk(ST_DEB_MSG "st: Buffer at %p normalized to %d bytes (segs %d).\n",
page_address(STbuffer->sg[0].page), STbuffer->buffer_size,
STbuffer->sg_segs);
STbuffer, STbuffer->buffer_size, STbuffer->sg_segs);
) /* end DEB */
STbuffer->sg_segs = STbuffer->orig_sg_segs;
}
......@@ -3619,18 +3475,16 @@ static int from_buffer(ST_buffer * st_bp, char *ubp, int do_count)
static void validate_options(void)
{
if (buffer_kbs > 0)
st_buffer_size = buffer_kbs * ST_KILOBYTE;
st_fixed_buffer_size = buffer_kbs * ST_KILOBYTE;
if (write_threshold_kbs > 0)
st_write_threshold = write_threshold_kbs * ST_KILOBYTE;
else if (buffer_kbs > 0)
st_write_threshold = st_buffer_size - 2048;
if (st_write_threshold > st_buffer_size) {
st_write_threshold = st_buffer_size;
st_write_threshold = st_fixed_buffer_size - 2048;
if (st_write_threshold > st_fixed_buffer_size) {
st_write_threshold = st_fixed_buffer_size;
printk(KERN_WARNING "st: write_threshold limited to %d bytes.\n",
st_write_threshold);
}
if (max_buffers >= 0)
st_max_buffers = max_buffers;
if (max_sg_segs >= ST_FIRST_SG)
st_max_sg_segs = max_sg_segs;
}
......@@ -3694,7 +3548,8 @@ static int st_attach(Scsi_Device * SDp)
Scsi_Tape *tpnt;
ST_mode *STm;
ST_partstat *STps;
int i, mode, target_nbr, dev_num;
ST_buffer *buffer;
int i, mode, dev_num;
char *stp;
if (SDp->type != TYPE_TAPE)
......@@ -3707,6 +3562,12 @@ static int st_attach(Scsi_Device * SDp)
return 1;
}
buffer = new_tape_buffer(TRUE, (SDp->host)->unchecked_isa_dma);
if (buffer == NULL) {
printk(KERN_ERR "st: Can't allocate new tape buffer. Device not attached.\n");
return 1;
}
write_lock(&st_dev_arr_lock);
if (st_template.nr_dev >= st_template.dev_max) {
Scsi_Tape **tmp_da;
......@@ -3745,14 +3606,6 @@ static int st_attach(Scsi_Device * SDp)
}
scsi_tapes = tmp_da;
memset(tmp_ba, 0, tmp_dev_max * sizeof(ST_buffer *));
if (st_buffers != NULL) {
memcpy(tmp_ba, st_buffers,
st_template.dev_max * sizeof(ST_buffer *));
kfree(st_buffers);
}
st_buffers = tmp_ba;
st_template.dev_max = tmp_dev_max;
}
......@@ -3799,6 +3652,9 @@ static int st_attach(Scsi_Device * SDp)
else
tpnt->tape_type = MT_ISSCSI2;
buffer->use_sg = tpnt->device->host->sg_tablesize;
tpnt->buffer = buffer;
tpnt->inited = 0;
tpnt->devt = mk_kdev(SCSI_TAPE_MAJOR, i);
tpnt->dirty = 0;
......@@ -3858,18 +3714,6 @@ static int st_attach(Scsi_Device * SDp)
"Attached scsi tape st%d at scsi%d, channel %d, id %d, lun %d\n",
dev_num, SDp->host->host_no, SDp->channel, SDp->id, SDp->lun);
/* See if we need to allocate more static buffers */
target_nbr = st_template.nr_dev;
if (target_nbr > st_max_buffers)
target_nbr = st_max_buffers;
for (i=st_nbr_buffers; i < target_nbr; i++)
if (!new_tape_buffer(TRUE, TRUE, FALSE)) {
printk(KERN_INFO "st: Unable to allocate new static buffer.\n");
break;
}
/* If the previous allocation fails, we will try again when the buffer is
really needed. */
return 0;
};
......@@ -3897,6 +3741,11 @@ static void st_detach(Scsi_Device * SDp)
devfs_unregister (tpnt->de_n[mode]);
tpnt->de_n[mode] = NULL;
}
if (tpnt->buffer) {
tpnt->buffer->orig_sg_segs = 0;
normalize_buffer(tpnt->buffer);
kfree(tpnt->buffer);
}
kfree(tpnt);
scsi_tapes[i] = 0;
SDp->attached--;
......@@ -3916,10 +3765,10 @@ static int __init init_st(void)
validate_options();
printk(KERN_INFO
"st: Version %s, bufsize %d, wrt %d, "
"max init. bufs %d, s/g segs %d\n",
verstr, st_buffer_size, st_write_threshold,
st_max_buffers, st_max_sg_segs);
"st: Version %s, fixed bufsize %d, wrt %d, "
"s/g segs %d\n",
verstr, st_fixed_buffer_size, st_write_threshold,
st_max_sg_segs);
if (devfs_register_chrdev(SCSI_TAPE_MAJOR, "st", &st_fops) >= 0)
return scsi_register_device(&st_template);
......@@ -3939,16 +3788,6 @@ static void __exit exit_st(void)
if (scsi_tapes[i])
kfree(scsi_tapes[i]);
kfree(scsi_tapes);
if (st_buffers != NULL) {
for (i = 0; i < st_nbr_buffers; i++) {
if (st_buffers[i] != NULL) {
st_buffers[i]->orig_sg_segs = 0;
normalize_buffer(st_buffers[i]);
kfree(st_buffers[i]);
}
}
kfree(st_buffers);
}
}
st_template.dev_max = 0;
printk(KERN_INFO "st: Unloaded.\n");
......
drivers/scsi/st_options.h
View file @ f179b6ce
......@@ -3,7 +3,7 @@
Copyright 1995-2000 Kai Makisara.
Last modified: Tue Jan 22 21:52:34 2002 by makisara
Last modified: Sun May 5 15:09:56 2002 by makisara
*/
#ifndef _ST_OPTIONS_H
......@@ -30,22 +30,17 @@
SENSE. */
#define ST_DEFAULT_BLOCK 0
/* The tape driver buffer size in kilobytes. Must be non-zero. */
#define ST_BUFFER_BLOCKS 32
/* The minimum tape driver buffer size in kilobytes in fixed block mode.
Must be non-zero. */
#define ST_FIXED_BUFFER_BLOCKS 32
/* The number of kilobytes of data in the buffer that triggers an
asynchronous write in fixed block mode. See also ST_ASYNC_WRITES
below. */
#define ST_WRITE_THRESHOLD_BLOCKS 30
/* The maximum number of tape buffers the driver tries to allocate at
driver initialisation. The number is also constrained by the number
of drives detected. If more buffers are needed, they are allocated
at run time and freed after use. */
#define ST_MAX_BUFFERS 4
/* Maximum number of scatter/gather segments */
#define ST_MAX_SG 16
#define ST_MAX_SG 64
/* The number of scatter/gather segments to allocate at first try (must be
smaller or equal to the maximum). */
......
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