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authorKai Makisara <Kai.Makisara@kolumbus.fi>2008-02-24 23:23:24 +0300
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-04-07 21:15:39 +0400
commit40f6b36c6243462fb95d0343237331c423494b03 (patch)
tree456b78c5647684527e0104463dd45b8e93ea9d81 /drivers/scsi/st.c
parentd35055a0f2637f29f95001a67b464fe833b09ebc (diff)
downloadlinux-40f6b36c6243462fb95d0343237331c423494b03.tar.xz
[SCSI] st: add option to use SILI in variable block reads
Add new option MT_ST_SILI to enable setting the SILI bit in reads in variable block mode. If SILI is set, reading a block shorter than the byte count does not result in CHECK CONDITION. The length of the block is determined using the residual count from the HBA. Avoiding the REQUEST SENSE command for every block speeds up some real applications considerably. Signed-off-by: Kai Makisara <kai.makisara@kolumbus.fi> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'drivers/scsi/st.c')
-rw-r--r--drivers/scsi/st.c40
1 files changed, 36 insertions, 4 deletions
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 0a52d9d2da2c..a4361a8c6ac6 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -17,7 +17,7 @@
Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
*/
-static const char *verstr = "20080221";
+static const char *verstr = "20080224";
#include <linux/module.h>
@@ -183,6 +183,7 @@ static int modes_defined;
static struct st_buffer *new_tape_buffer(int, int, int);
static int enlarge_buffer(struct st_buffer *, int, int);
+static void clear_buffer(struct st_buffer *);
static void normalize_buffer(struct st_buffer *);
static int append_to_buffer(const char __user *, struct st_buffer *, int);
static int from_buffer(struct st_buffer *, char __user *, int);
@@ -442,6 +443,7 @@ static void st_sleep_done(void *data, char *sense, int result, int resid)
memcpy(SRpnt->sense, sense, SCSI_SENSE_BUFFERSIZE);
(STp->buffer)->cmdstat.midlevel_result = SRpnt->result = result;
+ (STp->buffer)->cmdstat.residual = resid;
DEB( STp->write_pending = 0; )
if (SRpnt->waiting)
@@ -1159,6 +1161,7 @@ static int st_open(struct inode *inode, struct file *filp)
goto err_out;
}
+ (STp->buffer)->cleared = 0;
(STp->buffer)->writing = 0;
(STp->buffer)->syscall_result = 0;
@@ -1432,8 +1435,14 @@ static int setup_buffering(struct scsi_tape *STp, const char __user *buf,
if (STp->block_size)
bufsize = STp->block_size > st_fixed_buffer_size ?
STp->block_size : st_fixed_buffer_size;
- else
+ else {
bufsize = count;
+ /* Make sure that data from previous user is not leaked even if
+ HBA does not return correct residual */
+ if (is_read && STp->sili && !STbp->cleared)
+ clear_buffer(STbp);
+ }
+
if (bufsize > STbp->buffer_size &&
!enlarge_buffer(STbp, bufsize, STp->restr_dma)) {
printk(KERN_WARNING "%s: Can't allocate %d byte tape buffer.\n",
@@ -1783,6 +1792,8 @@ static long read_tape(struct scsi_tape *STp, long count,
memset(cmd, 0, MAX_COMMAND_SIZE);
cmd[0] = READ_6;
cmd[1] = (STp->block_size != 0);
+ if (!cmd[1] && STp->sili)
+ cmd[1] |= 2;
cmd[2] = blks >> 16;
cmd[3] = blks >> 8;
cmd[4] = blks;
@@ -1911,8 +1922,11 @@ static long read_tape(struct scsi_tape *STp, long count,
}
/* End of error handling */
- else /* Read successful */
+ else { /* Read successful */
STbp->buffer_bytes = bytes;
+ if (STp->sili) /* In fixed block mode residual is always zero here */
+ STbp->buffer_bytes -= STp->buffer->cmdstat.residual;
+ }
if (STps->drv_block >= 0) {
if (STp->block_size == 0)
@@ -2090,7 +2104,8 @@ static void st_log_options(struct scsi_tape * STp, struct st_modedef * STm, char
name, STm->defaults_for_writes, STp->omit_blklims, STp->can_partitions,
STp->scsi2_logical);
printk(KERN_INFO
- "%s: sysv: %d nowait: %d\n", name, STm->sysv, STp->immediate);
+ "%s: sysv: %d nowait: %d sili: %d\n", name, STm->sysv, STp->immediate,
+ STp->sili);
printk(KERN_INFO "%s: debugging: %d\n",
name, debugging);
}
@@ -2133,6 +2148,7 @@ static int st_set_options(struct scsi_tape *STp, long options)
STp->scsi2_logical = (options & MT_ST_SCSI2LOGICAL) != 0;
STp->immediate = (options & MT_ST_NOWAIT) != 0;
STm->sysv = (options & MT_ST_SYSV) != 0;
+ STp->sili = (options & MT_ST_SILI) != 0;
DEB( debugging = (options & MT_ST_DEBUGGING) != 0;
st_log_options(STp, STm, name); )
} else if (code == MT_ST_SETBOOLEANS || code == MT_ST_CLEARBOOLEANS) {
@@ -2164,6 +2180,8 @@ static int st_set_options(struct scsi_tape *STp, long options)
STp->immediate = value;
if ((options & MT_ST_SYSV) != 0)
STm->sysv = value;
+ if ((options & MT_ST_SILI) != 0)
+ STp->sili = value;
DEB(
if ((options & MT_ST_DEBUGGING) != 0)
debugging = value;
@@ -3655,6 +3673,8 @@ static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dm
STbuffer->frp_segs += 1;
got += b_size;
STbuffer->buffer_size = got;
+ if (STbuffer->cleared)
+ memset(page_address(STbuffer->frp[segs].page), 0, b_size);
segs++;
}
STbuffer->b_data = page_address(STbuffer->frp[0].page);
@@ -3663,6 +3683,17 @@ static int enlarge_buffer(struct st_buffer * STbuffer, int new_size, int need_dm
}
+/* Make sure that no data from previous user is in the internal buffer */
+static void clear_buffer(struct st_buffer * st_bp)
+{
+ int i;
+
+ for (i=0; i < st_bp->frp_segs; i++)
+ memset(page_address(st_bp->frp[i].page), 0, st_bp->frp[i].length);
+ st_bp->cleared = 1;
+}
+
+
/* Release the extra buffer */
static void normalize_buffer(struct st_buffer * STbuffer)
{
@@ -3987,6 +4018,7 @@ static int st_probe(struct device *dev)
tpnt->two_fm = ST_TWO_FM;
tpnt->fast_mteom = ST_FAST_MTEOM;
tpnt->scsi2_logical = ST_SCSI2LOGICAL;
+ tpnt->sili = ST_SILI;
tpnt->immediate = ST_NOWAIT;
tpnt->default_drvbuffer = 0xff; /* No forced buffering */
tpnt->partition = 0;