[SCSI] st: add option to use SILI in variable block reads

[linux-2.6-omap-h63xx.git] / drivers / scsi / st.c

diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 0a52d9d2da2cc43678c9d099aa0e00eb2b0ecfef..a4361a8c6ac653bc2295e02324528b5b80e8d2cc 100644 (file)
--- 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;