From 40f6b36c6243462fb95d0343237331c423494b03 Mon Sep 17 00:00:00 2001 From: Kai Makisara Date: Sun, 24 Feb 2008 22:23:24 +0200 Subject: [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 Signed-off-by: James Bottomley --- Documentation/scsi/st.txt | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt index b7be95b5bd24..38f81188def0 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: 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 @@ MTSETDRVBUFFER 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 -- cgit v1.2.3 From b174be02f3634460ac215d249617dee5ae446ae1 Mon Sep 17 00:00:00 2001 From: Kai Makisara Date: Sun, 24 Feb 2008 22:29:12 +0200 Subject: [SCSI] st: show options currently set in sysfs Show the current binary tape driver and mode options is sysfs. A file (options) is created in each directory in /sys/class/scsi_tape. The files contain masks showing the options. The mask bit definitions are the same as used when setting the options using the MTSETDRVBUFFER function in the MTIOCTOP ioctl (defined in include/linux/mtio.h). For example: > cat /sys/class/scsi_tape/nst0/options 0x00000d07 [jejb: updated doc with correction from Randy Dunlap] Signed-off-by: Kai Makisara Signed-off-by: James Bottomley --- Documentation/scsi/st.txt | 7 ++++++- drivers/scsi/st.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt index 38f81188def0..40752602c050 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: Thu Feb 21 21:54:16 2008 by kai.makisara +Last modified: Sun Feb 24 21:59:07 2008 by kai.makisara BASICS @@ -133,6 +133,11 @@ the defaults set by the user. The value -1 means the default is not set. The file 'dev' contains the device numbers corresponding to this device. The links 'device' and 'driver' point to the SCSI device and driver entries. +Each directory also contains the entry 'options' which shows the currently +enabled driver and mode options. The value in the file is a bit mask where the +bit definitions are the same as those used with MTSETDRVBUFFER in setting the +options. + A link named 'tape' is made from the SCSI device directory to the class directory corresponding to the mode 0 auto-rewind device (e.g., st0). diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c index a4361a8c6ac6..d204aad2e683 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -4365,6 +4365,46 @@ static ssize_t st_defcompression_show(struct class_device *class_dev, char *buf) CLASS_DEVICE_ATTR(default_compression, S_IRUGO, st_defcompression_show, NULL); +static ssize_t st_options_show(struct class_device *class_dev, char *buf) +{ + struct st_modedef *STm = (struct st_modedef *)class_get_devdata(class_dev); + struct scsi_tape *STp; + int i, j, options; + ssize_t l = 0; + + for (i=0; i < st_dev_max; i++) { + for (j=0; j < ST_NBR_MODES; j++) + if (&scsi_tapes[i]->modes[j] == STm) + break; + if (j < ST_NBR_MODES) + break; + } + if (i == st_dev_max) + return 0; /* should never happen */ + + STp = scsi_tapes[i]; + + options = STm->do_buffer_writes ? MT_ST_BUFFER_WRITES : 0; + options |= STm->do_async_writes ? MT_ST_ASYNC_WRITES : 0; + options |= STm->do_read_ahead ? MT_ST_READ_AHEAD : 0; + DEB( options |= debugging ? MT_ST_DEBUGGING : 0 ); + options |= STp->two_fm ? MT_ST_TWO_FM : 0; + options |= STp->fast_mteom ? MT_ST_FAST_MTEOM : 0; + options |= STm->defaults_for_writes ? MT_ST_DEF_WRITES : 0; + options |= STp->can_bsr ? MT_ST_CAN_BSR : 0; + options |= STp->omit_blklims ? MT_ST_NO_BLKLIMS : 0; + options |= STp->can_partitions ? MT_ST_CAN_PARTITIONS : 0; + options |= STp->scsi2_logical ? MT_ST_SCSI2LOGICAL : 0; + options |= STm->sysv ? MT_ST_SYSV : 0; + options |= STp->immediate ? MT_ST_NOWAIT : 0; + options |= STp->sili ? MT_ST_SILI : 0; + + l = snprintf(buf, PAGE_SIZE, "0x%08x\n", options); + return l; +} + +CLASS_DEVICE_ATTR(options, S_IRUGO, st_options_show, NULL); + static int do_create_class_files(struct scsi_tape *STp, int dev_num, int mode) { int i, rew, error; @@ -4402,6 +4442,9 @@ static int do_create_class_files(struct scsi_tape *STp, int dev_num, int mode) error = class_device_create_file(st_class_member, &class_device_attr_default_compression); if (error) goto out; + error = class_device_create_file(st_class_member, + &class_device_attr_options); + if (error) goto out; if (mode == 0 && rew == 0) { error = sysfs_create_link(&STp->device->sdev_gendev.kobj, -- cgit v1.2.3