3 files changed, 24 insertions, 7 deletions

diff --git a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt
index 40752602c050..691ca292c24d 100644
--- a/Documentation/scsi/st.txt
+++ b/Documentation/scsi/st.txt
@@ -2,7 +2,7 @@ This file contains brief information about the SCSI tape driver.
 The driver is currently maintained by Kai Mäkisara (email
 Kai.Makisara@kolumbus.fi)
 
-Last modified: Sun Feb 24 21:59:07 2008 by kai.makisara
+Last modified: Sun Aug 29 18:25:47 2010 by kai.makisara
 
 
 BASICS
@@ -85,6 +85,17 @@ writing and the last operation has been a write. Two filemarks can be
 optionally written. In both cases end of data is signified by
 returning zero bytes for two consecutive reads.
 
+Writing filemarks without the immediate bit set in the SCSI command block acts
+as a synchronization point, i.e., all remaining data form the drive buffers is
+written to tape before the command returns. This makes sure that write errors
+are caught at that point, but this takes time. In some applications, several
+consecutive files must be written fast. The MTWEOFI operation can be used to
+write the filemarks without flushing the drive buffer. Writing filemark at
+close() is always flushing the drive buffers. However, if the previous
+operation is MTWEOFI, close() does not write a filemark. This can be used if
+the program wants to close/open the tape device between files and wants to
+skip waiting.
+
 If rewind, offline, bsf, or seek is done and previous tape operation was
 write, a filemark is written before moving tape.
 
@@ -301,6 +312,8 @@ MTBSR   Space backward over count records.
 MTFSS   Space forward over count setmarks.
 MTBSS   Space backward over count setmarks.
 MTWEOF  Write count filemarks.
+MTWEOFI Write count filemarks with immediate bit set (i.e., does not
+        wait until data is on tape)
 MTWSM   Write count setmarks.
 MTREW   Rewind tape.
 MTOFFL  Set device off line (often rewind plus eject).
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 24211d0efa6d..9e2c3a72ff4d 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -9,7 +9,7 @@
    Steve Hirsch, Andreas Koppenh"ofer, Michael Leodolter, Eyal Lebedinsky,
    Michael Schaefer, J"org Weule, and Eric Youngdale.
 
-   Copyright 1992 - 2008 Kai Makisara
+   Copyright 1992 - 2010 Kai Makisara
    email Kai.Makisara@kolumbus.fi
 
    Some small formal changes - aeb, 950809
@@ -17,7 +17,7 @@
    Last modified: 18-JAN-1998 Richard Gooch <rgooch@atnf.csiro.au> Devfs support
  */
 
-static const char *verstr = "20081215";
+static const char *verstr = "20100829";
 
 #include <linux/module.h>
 
@@ -2696,18 +2696,21 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
                 }
                 break;
         case MTWEOF:
+        case MTWEOFI:
         case MTWSM:
                 if (STp->write_prot)
                         return (-EACCES);
                 cmd[0] = WRITE_FILEMARKS;
                 if (cmd_in == MTWSM)
                         cmd[1] = 2;
+                if (cmd_in == MTWEOFI)
+                        cmd[1] |= 1;
                 cmd[2] = (arg >> 16);
                 cmd[3] = (arg >> 8);
                 cmd[4] = arg;
                 timeout = STp->device->request_queue->rq_timeout;
                 DEBC(
-                     if (cmd_in == MTWEOF)
+                     if (cmd_in != MTWSM)
                                printk(ST_DEB_MSG "%s: Writing %d filemarks.\n", name,
                                  cmd[2] * 65536 + cmd[3] * 256 + cmd[4]);
                      else
@@ -2883,8 +2886,8 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
                 else if (chg_eof)
                         STps->eof = ST_NOEOF;
 
-                if (cmd_in == MTWEOF)
-                        STps->rw = ST_IDLE;
+                if (cmd_in == MTWEOF || cmd_in == MTWEOFI)
+                        STps->rw = ST_IDLE;  /* prevent automatic WEOF at close */
         } else { /* SCSI command was not completely successful. Don't return
                     from this block without releasing the SCSI command block! */
                 struct st_cmdstatus *cmdstatp = &STp->buffer->cmdstat;
@@ -2901,7 +2904,7 @@ static int st_int_ioctl(struct scsi_tape *STp, unsigned int cmd_in, unsigned lon
                 else
                         undone = 0;
 
-                if (cmd_in == MTWEOF &&
+                if ((cmd_in == MTWEOF || cmd_in == MTWEOFI) &&
                     cmdstatp->have_sense &&
                     (cmdstatp->flags & SENSE_EOM)) {
                         if (cmdstatp->sense_hdr.sense_key == NO_SENSE ||
diff --git a/include/linux/mtio.h b/include/linux/mtio.h
index ef01d6aa5934..8f825756c459 100644
--- a/include/linux/mtio.h
+++ b/include/linux/mtio.h
@@ -63,6 +63,7 @@ struct	mtop {
 #define MTCOMPRESSION 32/* control compression with SCSI mode page 15 */
 #define MTSETPART 33    /* Change the active tape partition */
 #define MTMKPART  34    /* Format the tape with one or two partitions */
+#define MTWEOFI 35      /* write an end-of-file record (mark) in immediate mode */
 
 /* structure for MTIOCGET - mag tape get status command */