diff --git a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt
index b7be95b..38f8118 100644
--- a/Documentation/scsi/st.txt
+++ b/Documentation/scsi/st.txt
@@ -2,7 +2,7 @@
 The driver is currently maintained by Kai Mäkisara (email
 Kai.Makisara@kolumbus.fi)
 
-Last modified: Mon Mar  7 21:14:44 2005 by kai.makisara
+Last modified: Thu Feb 21 21:54:16 2008 by kai.makisara
 
 
 BASICS
@@ -372,6 +372,11 @@
 	     MT_ST_SYSV sets the SYSV semantics (mode)
 	     MT_ST_NOWAIT enables immediate mode (i.e., don't wait for
 	        the command to finish) for some commands (e.g., rewind)
+	     MT_ST_SILI enables setting the SILI bit in SCSI commands when
+		reading in variable block mode to enhance performance when
+		reading blocks shorter than the byte count; set this only
+		if you are sure that the drive supports SILI and the HBA
+		correctly returns transfer residuals
 	     MT_ST_DEBUGGING debugging (global; debugging must be
 		compiled into the driver)
 	MT_ST_SETBOOLEANS
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 0a52d9d..a4361a8 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 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 @@
 
 	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 @@
 		goto err_out;
 	}
 
+	(STp->buffer)->cleared = 0;
 	(STp->buffer)->writing = 0;
 	(STp->buffer)->syscall_result = 0;
 
@@ -1432,8 +1435,14 @@
 		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 @@
 	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 @@
 
 	}
 	/* 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 @@
 		       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 @@
 		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 @@
 			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 @@
 		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 @@
 }
 
 
+/* 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 @@
 	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;
diff --git a/drivers/scsi/st.h b/drivers/scsi/st.h
index 5931726..b92712f 100644
--- a/drivers/scsi/st.h
+++ b/drivers/scsi/st.h
@@ -12,6 +12,7 @@
 	int midlevel_result;
 	struct scsi_sense_hdr sense_hdr;
 	int have_sense;
+	int residual;
 	u64 uremainder64;
 	u8 flags;
 	u8 remainder_valid;
@@ -34,6 +35,7 @@
 struct st_buffer {
 	unsigned char dma;	/* DMA-able buffer */
 	unsigned char do_dio;   /* direct i/o set up? */
+	unsigned char cleared;  /* internal buffer cleared after open? */
 	int buffer_size;
 	int buffer_blocks;
 	int buffer_bytes;
@@ -122,6 +124,7 @@
 	unsigned char try_dio_now;		/* try direct i/o before next close? */
 	unsigned char c_algo;			/* compression algorithm */
 	unsigned char pos_unknown;			/* after reset position unknown */
+	unsigned char sili;			/* use SILI when reading in variable b mode */
 	int tape_type;
 	int long_timeout;	/* timeout for commands known to take long time */
 
diff --git a/drivers/scsi/st_options.h b/drivers/scsi/st_options.h
index b6b5c9c..d2f9479 100644
--- a/drivers/scsi/st_options.h
+++ b/drivers/scsi/st_options.h
@@ -3,7 +3,7 @@
 
    Copyright 1995-2003 Kai Makisara.
 
-   Last modified: Mon Apr  7 22:49:18 2003 by makisara
+   Last modified: Thu Feb 21 21:47:07 2008 by kai.makisara
 */
 
 #ifndef _ST_OPTIONS_H
@@ -94,6 +94,10 @@
    The default is BSD semantics. */
 #define ST_SYSV 0
 
+/* If ST_SILI is non-zero, the SILI bit is set when reading in variable block
+   mode and the block size is determined using the residual returned by the HBA. */
+#define ST_SILI 0
+
 /* Time to wait for the drive to become ready if blocking open */
 #define ST_BLOCK_SECONDS     120
 
diff --git a/include/linux/mtio.h b/include/linux/mtio.h
index 6f8d2d4..ef01d6a 100644
--- a/include/linux/mtio.h
+++ b/include/linux/mtio.h
@@ -192,6 +192,7 @@
 #define MT_ST_SCSI2LOGICAL      0x800
 #define MT_ST_SYSV              0x1000
 #define MT_ST_NOWAIT            0x2000
+#define MT_ST_SILI		0x4000
 
 /* The mode parameters to be controlled. Parameter chosen with bits 20-28 */
 #define MT_ST_CLEAR_DEFAULT	0xfffff