Re: [PATCH]: add debug flag parameter for SCSI tape driver - 2nd request
Thanks, I've applied this patch to the core-for-3.19 branch after fixing a few whitespace issues. -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH]: add debug flag parameter for SCSI tape driver - 2nd request
Hello,
I am responding to this, but noticed your next, fixed version.
On 17.10.2014, at 23.20, Laurence Oberman lober...@redhat.com wrote:
Hello Kai
You have seen this patch before. The first time around, given that we don't
enable DEBUG by default, I let it go.
However we have been looking into defining DEBUG 1 by default here at Redhat
and then setting the default to disabled.
Are you open to considering changing the driver based on this patch.
i.e. default DEFINE 1 and adding this code with default set to off.
Yes. I certainly think defining DEBUG 1 and changing the default to zero should
be done if it is useful for supporting users. The runtime overhead is
negligible and the extra code does not matter nowadays (it did matter, at least
theoretically, for years ago).
I am not so sure about the module option. When the debugging code is compiled
in, debugging can be enabled and disabled for each device by the MTIOCTOP ioctl
(e.g., mtst -f tape_device stsetoptions debug). The module option enables
debugging for all tape devices. However, if you think this additional module
option is useful, I am not against it. It does not remove the possibility for
controlling debugging for each device for those who want to do it that way.
Anyway, you should modify the documentation (Documentation/scsi/st.txt)
according to the changes.
Note that with DEBUG 0, as you know you need to change that and recompile.
That is exactly what I am trying to avoid with Enterprise customers.
I have also noticed this when someone has asked me about some tape problems.
This patch adds a debug_flag parameter that can be set on module load, and
allows the DEBUG facility without a module recompile.
Note that now DEBUG 1 is the default with this patch.
Usage: modprobe st debug_flag=1
Signed-off-by: Laurence Oberman lober...@redhat.com
diff -Nur a/st.c b/st.c
--- a/st.c2014-10-17 16:15:54.103810627 -0400
+++ b/st.c2014-10-17 16:22:12.303810392 -0400
@@ -56,7 +56,7 @@
/* The driver prints some debugging information on the console if DEBUG
is defined and non-zero. */
-#define DEBUG 0
+#define DEBUG 1
#define ST_DEB_MSG KERN_NOTICE
#if DEBUG
@@ -80,6 +80,7 @@
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = 1;
static int try_wdio = 1;
+static int debug_flag = 0;
static struct class st_sysfs_class;
static const struct attribute_group *st_dev_groups[];
@@ -100,6 +101,9 @@
MODULE_PARM_DESC(max_sg_segs, Maximum number of scatter/gather segments to
use (256));
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, Try direct I/O between user buffer and tape
drive (1));
+module_param_named(debug_flag, debug_flag, int, 0);
+MODULE_PARM_DESC(debug_flag, Enable DEBUG, same as setting debugging=1);
+
/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
@@ -124,6 +128,9 @@
},
{
try_direct_io, try_direct_io
+},
+{
+debug_flag, debug_flag
}
};
#endif
@@ -4306,6 +4313,11 @@
validate_options();
+debugging = (debug_flag 0) ? debug_flag : DEBUG;
+ if (debugging)
+printk(KERN_INFO st: Debugging enabled debug_flag =
%d\n,debugging);
+
+
I think you have an extra newline here?
I also think that the kernel log would look nicer if the print below would be
before setting the option. The driver would introduce itself first and print
the debug flag status after that.
printk(KERN_INFO st: Version %s, fixed bufsize %d, s/g segs %d\n,
verstr, st_fixed_buffer_size, st_max_sg_segs);
Thanks,
Kai
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Re: [PATCH]: add debug flag parameter for SCSI tape driver - 2nd request
Hello Kai
Thanks.
Here is v3
This patch adds a debug_flag parameter that can be set on module load, and
allows the DEBUG facility without a module recompile.
Note that now DEBUG 1 is the default with this patch.
Usage: modprobe st debug_flag=1
Signed-off-by: Laurence Oberman lober...@redhat.com
diff -Nur a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt
--- a/Documentation/scsi/st.txt 2014-10-19 09:36:52.243863716 -0400
+++ b/Documentation/scsi/st.txt 2014-10-19 09:43:19.222863447 -0400
@@ -506,9 +506,11 @@
DEBUGGING HINTS
-To enable debugging messages, edit st.c and #define DEBUG 1. As seen
-above, debugging can be switched off with an ioctl if debugging is
-compiled into the driver. The debugging output is not voluminous.
+Debugging code is now compiled in by default but debugging is turned off with
+the kernel module parameter debug_flag defaulting to 0.
+Debugging can still be switched on and off with an ioctl.
+To enable debug at module load time add debug_flag=1 to the module load
+options, the debugging output is not voluminous.
If the tape seems to hang, I would be very interested to hear where
the driver is waiting. With the command 'ps -l' you can see the state
diff -Nur a/drivers/scsi/st.c b/drivers/scsi/st.c
--- a/drivers/scsi/st.c 2014-10-19 09:35:45.673863756 -0400
+++ b/drivers/scsi/st.c 2014-10-19 09:35:30.621863483 -0400
@@ -56,7 +56,8 @@
/* The driver prints some debugging information on the console if DEBUG
is defined and non-zero. */
-#define DEBUG 0
+#define DEBUG 1
+#define NO_DEBUG 0
#define ST_DEB_MSG KERN_NOTICE
#if DEBUG
@@ -80,6 +81,7 @@
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = 1;
static int try_wdio = 1;
+static int debug_flag = 0;
static struct class st_sysfs_class;
static const struct attribute_group *st_dev_groups[];
@@ -100,6 +102,9 @@
MODULE_PARM_DESC(max_sg_segs, Maximum number of scatter/gather segments to
use (256));
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, Try direct I/O between user buffer and tape
drive (1));
+module_param_named(debug_flag, debug_flag, int, 0);
+MODULE_PARM_DESC(debug_flag, Enable DEBUG, same as setting debugging=1);
+
/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
@@ -124,6 +129,9 @@
},
{
try_direct_io, try_direct_io
+},
+{
+debug_flag, debug_flag
}
};
#endif
@@ -4309,6 +4317,10 @@
printk(KERN_INFO st: Version %s, fixed bufsize %d, s/g segs %d\n,
verstr, st_fixed_buffer_size, st_max_sg_segs);
+debugging = (debug_flag 0) ? debug_flag : NO_DEBUG;
+ if (debugging)
+printk(KERN_INFO st: Debugging enabled debug_flag =
%d\n,debugging);
+
err = class_register(st_sysfs_class);
if (err) {
pr_err(Unable register sysfs class for SCSI tapes\n);
- Original Message -
From: Kai Mäkisara (Kolumbus) kai.makis...@kolumbus.fi
To: Laurence Oberman lober...@redhat.com
Cc: Rob Evers rev...@redhat.com, linux-scsi@vger.kernel.org
Sent: Sunday, October 19, 2014 4:54:10 AM
Subject: Re: [PATCH]: add debug flag parameter for SCSI tape driver - 2nd
request
Hello,
I am responding to this, but noticed your next, fixed version.
On 17.10.2014, at 23.20, Laurence Oberman lober...@redhat.com wrote:
Hello Kai
You have seen this patch before. The first time around, given that we don't
enable DEBUG by default, I let it go.
However we have been looking into defining DEBUG 1 by default here at Redhat
and then setting the default to disabled.
Are you open to considering changing the driver based on this patch.
i.e. default DEFINE 1 and adding this code with default set to off.
Yes. I certainly think defining DEBUG 1 and changing the default to zero should
be done if it is useful for supporting users. The runtime overhead is
negligible and the extra code does not matter nowadays (it did matter, at least
theoretically, for years ago).
I am not so sure about the module option. When the debugging code is compiled
in, debugging can be enabled and disabled for each device by the MTIOCTOP ioctl
(e.g., mtst -f tape_device stsetoptions debug). The module option enables
debugging for all tape devices. However, if you think this additional module
option is useful, I am not against it. It does not remove the possibility for
controlling debugging for each device for those who want to do it that way.
Anyway, you should modify the documentation (Documentation/scsi/st.txt)
according to the changes.
Note that with DEBUG 0, as you know you need to change that and recompile.
That is exactly what I am trying to avoid with Enterprise customers.
I have also noticed this when someone has asked me about some tape problems.
This patch adds a debug_flag parameter that can be set on module load, and
allows the DEBUG facility without a module
Re: [PATCH]: add debug flag parameter for SCSI tape driver - 2nd request
On 19.10.2014, at 16.44, Laurence Oberman lober...@redhat.com wrote:
Hello Kai
Thanks.
Here is v3
This patch adds a debug_flag parameter that can be set on module load, and
allows the DEBUG facility without a module recompile.
Note that now DEBUG 1 is the default with this patch.
Usage: modprobe st debug_flag=1
Signed-off-by: Laurence Oberman lober...@redhat.com
Acked-by: Kai Mäkisara kai.makis...@kolumbus.fi
Thanks,
Kai
diff -Nur a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt
--- a/Documentation/scsi/st.txt 2014-10-19 09:36:52.243863716 -0400
+++ b/Documentation/scsi/st.txt 2014-10-19 09:43:19.222863447 -0400
@@ -506,9 +506,11 @@
DEBUGGING HINTS
-To enable debugging messages, edit st.c and #define DEBUG 1. As seen
-above, debugging can be switched off with an ioctl if debugging is
-compiled into the driver. The debugging output is not voluminous.
+Debugging code is now compiled in by default but debugging is turned off
with
+the kernel module parameter debug_flag defaulting to 0.
+Debugging can still be switched on and off with an ioctl.
+To enable debug at module load time add debug_flag=1 to the module load
+options, the debugging output is not voluminous.
If the tape seems to hang, I would be very interested to hear where
the driver is waiting. With the command 'ps -l' you can see the state
diff -Nur a/drivers/scsi/st.c b/drivers/scsi/st.c
--- a/drivers/scsi/st.c 2014-10-19 09:35:45.673863756 -0400
+++ b/drivers/scsi/st.c 2014-10-19 09:35:30.621863483 -0400
@@ -56,7 +56,8 @@
/* The driver prints some debugging information on the console if DEBUG
is defined and non-zero. */
-#define DEBUG 0
+#define DEBUG 1
+#define NO_DEBUG 0
#define ST_DEB_MSG KERN_NOTICE
#if DEBUG
@@ -80,6 +81,7 @@
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = 1;
static int try_wdio = 1;
+static int debug_flag = 0;
static struct class st_sysfs_class;
static const struct attribute_group *st_dev_groups[];
@@ -100,6 +102,9 @@
MODULE_PARM_DESC(max_sg_segs, Maximum number of scatter/gather segments to
use (256));
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, Try direct I/O between user buffer and tape
drive (1));
+module_param_named(debug_flag, debug_flag, int, 0);
+MODULE_PARM_DESC(debug_flag, Enable DEBUG, same as setting debugging=1);
+
/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
@@ -124,6 +129,9 @@
},
{
try_direct_io, try_direct_io
+},
+{
+debug_flag, debug_flag
}
};
#endif
@@ -4309,6 +4317,10 @@
printk(KERN_INFO st: Version %s, fixed bufsize %d, s/g segs %d\n,
verstr, st_fixed_buffer_size, st_max_sg_segs);
+debugging = (debug_flag 0) ? debug_flag : NO_DEBUG;
+ if (debugging)
+printk(KERN_INFO st: Debugging enabled debug_flag =
%d\n,debugging);
+
err = class_register(st_sysfs_class);
if (err) {
pr_err(Unable register sysfs class for SCSI tapes\n);
--
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Re: [PATCH]: add debug flag parameter for SCSI tape driver - 2nd request
Hello Kai
You have seen this patch before. The first time around, given that we don't
enable DEBUG by default, I let it go.
However we have been looking into defining DEBUG 1 by default here at Redhat
and then setting the default to disabled.
Are you open to considering changing the driver based on this patch.
i.e. default DEFINE 1 and adding this code with default set to off.
Note that with DEBUG 0, as you know you need to change that and recompile.
That is exactly what I am trying to avoid with Enterprise customers.
This patch adds a debug_flag parameter that can be set on module load, and
allows the DEBUG facility without a module recompile.
Note that now DEBUG 1 is the default with this patch.
Usage: modprobe st debug_flag=1
Signed-off-by: Laurence Oberman lober...@redhat.com
diff -Nur a/st.c b/st.c
--- a/st.c 2014-10-17 16:15:54.103810627 -0400
+++ b/st.c 2014-10-17 16:22:12.303810392 -0400
@@ -56,7 +56,7 @@
/* The driver prints some debugging information on the console if DEBUG
is defined and non-zero. */
-#define DEBUG 0
+#define DEBUG 1
#define ST_DEB_MSG KERN_NOTICE
#if DEBUG
@@ -80,6 +80,7 @@
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = 1;
static int try_wdio = 1;
+static int debug_flag = 0;
static struct class st_sysfs_class;
static const struct attribute_group *st_dev_groups[];
@@ -100,6 +101,9 @@
MODULE_PARM_DESC(max_sg_segs, Maximum number of scatter/gather segments to
use (256));
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, Try direct I/O between user buffer and tape
drive (1));
+module_param_named(debug_flag, debug_flag, int, 0);
+MODULE_PARM_DESC(debug_flag, Enable DEBUG, same as setting debugging=1);
+
/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
@@ -124,6 +128,9 @@
},
{
try_direct_io, try_direct_io
+},
+{
+debug_flag, debug_flag
}
};
#endif
@@ -4306,6 +4313,11 @@
validate_options();
+debugging = (debug_flag 0) ? debug_flag : DEBUG;
+ if (debugging)
+printk(KERN_INFO st: Debugging enabled debug_flag =
%d\n,debugging);
+
+
printk(KERN_INFO st: Version %s, fixed bufsize %d, s/g segs %d\n,
verstr, st_fixed_buffer_size, st_max_sg_segs);
--
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Re: [PATCH]: add debug flag parameter for SCSI tape driver - 2nd request
Oops, patch was defaulting to 1.
Here is v2 properly defining DEBUG 1 and defaulting to 0 unless debug_flag=1
This patch adds a debug_flag parameter that can be set on module load, and
allows the DEBUG facility without a module recompile.
Note that now DEBUG 1 is the default with this patch.
Usage: modprobe st
Signed-off-by: Laurence Oberman lober...@redhat.com
diff -Nur a/st.c b/st.c
--- a/st.c 2014-10-17 16:15:54.103810627 -0400
+++ b/st.c 2014-10-17 16:42:45.992809531 -0400
@@ -56,7 +56,8 @@
/* The driver prints some debugging information on the console if DEBUG
is defined and non-zero. */
-#define DEBUG 0
+#define DEBUG 1
+#define NO_DEBUG 0
#define ST_DEB_MSG KERN_NOTICE
#if DEBUG
@@ -80,6 +81,7 @@
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = 1;
static int try_wdio = 1;
+static int debug_flag = 0;
static struct class st_sysfs_class;
static const struct attribute_group *st_dev_groups[];
@@ -100,6 +102,9 @@
MODULE_PARM_DESC(max_sg_segs, Maximum number of scatter/gather segments to
use (256));
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, Try direct I/O between user buffer and tape
drive (1));
+module_param_named(debug_flag, debug_flag, int, 0);
+MODULE_PARM_DESC(debug_flag, Enable DEBUG, same as setting debugging=1);
+
/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
@@ -124,6 +129,9 @@
},
{
try_direct_io, try_direct_io
+},
+{
+debug_flag, debug_flag
}
};
#endif
@@ -4306,6 +4314,11 @@
validate_options();
+debugging = (debug_flag 0) ? debug_flag : NO_DEBUG;
+ if (debugging)
+printk(KERN_INFO st: Debugging enabled debug_flag =
%d\n,debugging);
+
+
printk(KERN_INFO st: Version %s, fixed bufsize %d, s/g segs %d\n,
verstr, st_fixed_buffer_size, st_max_sg_segs);
- Original Message -
From: Laurence Oberman lober...@redhat.com
To: Kai Mäkisara (Kolumbus) kai.makis...@kolumbus.fi, Rob Evers
rev...@redhat.com
Cc: linux-scsi@vger.kernel.org
Sent: Friday, October 17, 2014 4:20:29 PM
Subject: Re: [PATCH]: add debug flag parameter for SCSI tape driver - 2nd
request
Hello Kai
You have seen this patch before. The first time around, given that we don't
enable DEBUG by default, I let it go.
However we have been looking into defining DEBUG 1 by default here at Redhat
and then setting the default to disabled.
Are you open to considering changing the driver based on this patch.
i.e. default DEFINE 1 and adding this code with default set to off.
Note that with DEBUG 0, as you know you need to change that and recompile.
That is exactly what I am trying to avoid with Enterprise customers.
This patch adds a debug_flag parameter that can be set on module load, and
allows the DEBUG facility without a module recompile.
Note that now DEBUG 1 is the default with this patch.
Usage: modprobe st debug_flag=1
Signed-off-by: Laurence Oberman lober...@redhat.com
diff -Nur a/st.c b/st.c
--- a/st.c 2014-10-17 16:15:54.103810627 -0400
+++ b/st.c 2014-10-17 16:22:12.303810392 -0400
@@ -56,7 +56,7 @@
/* The driver prints some debugging information on the console if DEBUG
is defined and non-zero. */
-#define DEBUG 0
+#define DEBUG 1
#define ST_DEB_MSG KERN_NOTICE
#if DEBUG
@@ -80,6 +80,7 @@
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = 1;
static int try_wdio = 1;
+static int debug_flag = 0;
static struct class st_sysfs_class;
static const struct attribute_group *st_dev_groups[];
@@ -100,6 +101,9 @@
MODULE_PARM_DESC(max_sg_segs, Maximum number of scatter/gather segments to
use (256));
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, Try direct I/O between user buffer and tape
drive (1));
+module_param_named(debug_flag, debug_flag, int, 0);
+MODULE_PARM_DESC(debug_flag, Enable DEBUG, same as setting debugging=1);
+
/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
@@ -124,6 +128,9 @@
},
{
try_direct_io, try_direct_io
+},
+{
+debug_flag, debug_flag
}
};
#endif
@@ -4306,6 +4313,11 @@
validate_options();
+debugging = (debug_flag 0) ? debug_flag : DEBUG;
+ if (debugging)
+printk(KERN_INFO st: Debugging enabled debug_flag =
%d\n,debugging);
+
+
printk(KERN_INFO st: Version %s, fixed bufsize %d, s/g segs %d\n,
verstr, st_fixed_buffer_size, st_max_sg_segs);
--
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Re: Debug flag parameter for SCSI tape driver
Are ANSI-formatted tapes used on Linux? That is, tapes that contain multiple files and use the the ANSI (= ECMA-13) tape labels. My uderstanding is that a lot of the modern cartridge tapes record only fixed-length blocks and/or that is how they are always used these days. Dale -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH]: add debug flag parameter for SCSI tape driver
On 11.6.2014, at 2.48, Laurence Oberman lober...@redhat.com wrote: Hello Take 2 of this patch, changed module description and subject line. This patch adds a debug_flag parameter that can be set on module load, and allows the DEBUG facility without a module recompile. Usage: mpdprobe st debug_flag=1 Signed-off-by: Laurence Oberman lober...@redhat.com What is wrong with the existing methods to control debugging? You can enable and disable debugging for each device with ioctl() (as described in the driver documentation). You can use mt-st to do this from command line. Your patch just allows one to change the default for all devices. The real problem may be that the distributions don’t compile the debugging code into the drivets but your patch does not change this. Kai -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH]: add debug flag parameter for SCSI tape driver
Kai, Thank you for considering this. With #define DEBUG 0 We still include #define DEB(a) #define DEBC(a) With the debug_flag we then provide the needed debug I am looking for at module load time. But I agree that it enables it for all devices and that may not be optimal I don't change the default, I just allow the parameter to control it. In the last few issues I have been working I have had to recompile and provide the st module to get what I needed captured for debugging so I decided to try the patch submission. Thank You Laurence - Original Message - From: Kai Mäkisara (Kolumbus) kai.makis...@kolumbus.fi To: Laurence Oberman lober...@redhat.com Cc: linux-scsi@vger.kernel.org Sent: Wednesday, June 11, 2014 2:03:15 PM Subject: Re: [PATCH]: add debug flag parameter for SCSI tape driver On 11.6.2014, at 2.48, Laurence Oberman lober...@redhat.com wrote: Hello Take 2 of this patch, changed module description and subject line. This patch adds a debug_flag parameter that can be set on module load, and allows the DEBUG facility without a module recompile. Usage: mpdprobe st debug_flag=1 Signed-off-by: Laurence Oberman lober...@redhat.com What is wrong with the existing methods to control debugging? You can enable and disable debugging for each device with ioctl() (as described in the driver documentation). You can use mt-st to do this from command line. Your patch just allows one to change the default for all devices. The real problem may be that the distributions don’t compile the debugging code into the drivets but your patch does not change this. Kai -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH]: add debug flag parameter for SCSI tape driver
This thread leads me to ask: Do people use ANSI-formatted tapes any more? That is, tape volumes with miltiple files, header and trailer labels, etc.? Dale -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH]: add debug flag parameter for SCSI tape driver
Kai, Its likely not worth doing this, I cross checked and indeed many distros have this compiled out. So lets leave it as is. Thanks Laurence - Original Message - From: Laurence Oberman lober...@redhat.com To: Kai Mäkisara (Kolumbus) kai.makis...@kolumbus.fi Cc: linux-scsi@vger.kernel.org Sent: Wednesday, June 11, 2014 2:24:25 PM Subject: Re: [PATCH]: add debug flag parameter for SCSI tape driver Kai, Thank you for considering this. With #define DEBUG 0 We still include #define DEB(a) #define DEBC(a) With the debug_flag we then provide the needed debug I am looking for at module load time. But I agree that it enables it for all devices and that may not be optimal I don't change the default, I just allow the parameter to control it. In the last few issues I have been working I have had to recompile and provide the st module to get what I needed captured for debugging so I decided to try the patch submission. Thank You Laurence - Original Message - From: Kai Mäkisara (Kolumbus) kai.makis...@kolumbus.fi To: Laurence Oberman lober...@redhat.com Cc: linux-scsi@vger.kernel.org Sent: Wednesday, June 11, 2014 2:03:15 PM Subject: Re: [PATCH]: add debug flag parameter for SCSI tape driver On 11.6.2014, at 2.48, Laurence Oberman lober...@redhat.com wrote: Hello Take 2 of this patch, changed module description and subject line. This patch adds a debug_flag parameter that can be set on module load, and allows the DEBUG facility without a module recompile. Usage: mpdprobe st debug_flag=1 Signed-off-by: Laurence Oberman lober...@redhat.com What is wrong with the existing methods to control debugging? You can enable and disable debugging for each device with ioctl() (as described in the driver documentation). You can use mt-st to do this from command line. Your patch just allows one to change the default for all devices. The real problem may be that the distributions don’t compile the debugging code into the drivets but your patch does not change this. Kai -- To unsubscribe from this list: send the line unsubscribe linux-scsi in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Debug flag parameter for SCSI tape driver
Hello
I am tired of building modules to enable SCSI tape driver debug so I am hoping
this patch is acceptable.
Tested using kernel 3.14.6
Usage example:
modprobe st debug_flag=1
diff -Nur a/st.c b/st.c
--- a/st.c 2014-06-10 16:45:18.522354105 -0400
+++ b/st.c 2014-06-10 16:45:33.953765908 -0400
@@ -80,6 +80,7 @@
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = 1;
static int try_wdio = 1;
+static int debug_flag = 0;
static struct class st_sysfs_class;
static const struct attribute_group *st_dev_groups[];
@@ -100,6 +101,9 @@
MODULE_PARM_DESC(max_sg_segs, Maximum number of scatter/gather segments to
use (256));
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, Try direct I/O between user buffer and tape
drive (1));
+module_param_named(debug_flag, debug_flag, int, 0);
+MODULE_PARM_DESC(debug_flag, Enable DEBUG, same as setting DEBUG 1 in
source);
+
/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
@@ -124,6 +128,9 @@
},
{
try_direct_io, try_direct_io
+ },
+ {
+ debug_flag, debug_flag
}
};
#endif
@@ -4277,7 +4284,9 @@
static int __init init_st(void)
{
int err;
-
+ debugging = (debug_flag 0) ? debug_flag : DEBUG;
+if (debugging)
+ printk(KERN_INFO st: Debugging enabled debug_flag =
%d\n,debugging);
validate_options();
printk(KERN_INFO st: Version %s, fixed bufsize %d, s/g segs %d\n,
Thanks
Laurence
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[PATCH]: add debug flag parameter for SCSI tape driver
Hello
Take 2 of this patch, changed module description and subject line.
This patch adds a debug_flag parameter that can be set on module load, and
allows the DEBUG facility without a module recompile.
Usage: mpdprobe st debug_flag=1
Signed-off-by: Laurence Oberman lober...@redhat.com
diff -Nur a/st.c b/st.c
--- a/st.c 2014-06-10 16:45:18.522354105 -0400
+++ b/st.c 2014-06-10 19:40:39.774387990 -0400
@@ -80,6 +80,7 @@
static int try_direct_io = TRY_DIRECT_IO;
static int try_rdio = 1;
static int try_wdio = 1;
+static int debug_flag = 0;
static struct class st_sysfs_class;
static const struct attribute_group *st_dev_groups[];
@@ -100,6 +101,9 @@
MODULE_PARM_DESC(max_sg_segs, Maximum number of scatter/gather segments to
use (256));
module_param_named(try_direct_io, try_direct_io, int, 0);
MODULE_PARM_DESC(try_direct_io, Try direct I/O between user buffer and tape
drive (1));
+module_param_named(debug_flag, debug_flag, int, 0);
+MODULE_PARM_DESC(debug_flag, Enable DEBUG, same as setting debugging=1);
+
/* Extra parameters for testing */
module_param_named(try_rdio, try_rdio, int, 0);
@@ -124,6 +128,9 @@
},
{
try_direct_io, try_direct_io
+ },
+ {
+ debug_flag, debug_flag
}
};
#endif
@@ -4277,7 +4284,9 @@
static int __init init_st(void)
{
int err;
-
+ debugging = (debug_flag 0) ? debug_flag : DEBUG;
+if (debugging)
+ printk(KERN_INFO st: Debugging enabled debug_flag =
%d\n,debugging);
validate_options();
printk(KERN_INFO st: Version %s, fixed bufsize %d, s/g segs %d\n,
Thanks
Laurence
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