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| author | Laurence Oberman <loberman@redhat.com> | 2014-10-19 09:44:25 -0400 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-11-12 11:15:55 +0100 |
| commit | 2bec708a88ce053ffcb0dd8e373d1e46c6dc38a4 (patch) | |
| tree | 20eb3509ee246f92dc86fb2ddd9aa3ad08e93ef5 | |
| parent | 26cf591e6dfc0d07495b7bcf20a557b316811f00 (diff) | |
| download | linux-2bec708a88ce053ffcb0dd8e373d1e46c6dc38a4.tar.bz2 | |
st: add a debug_flag module parameter request
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 <loberman@redhat.com>
Acked-by: Kai M??kisara <kai.makisara@kolumbus.fi>
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | Documentation/scsi/st.txt | 8 | ||||
| -rw-r--r-- | drivers/scsi/st.c | 16 |
2 files changed, 20 insertions, 4 deletions
diff --git a/Documentation/scsi/st.txt b/Documentation/scsi/st.txt index f346abbdd6ff..0d5bdb153d3b 100644 --- a/Documentation/scsi/st.txt +++ b/Documentation/scsi/st.txt @@ -506,9 +506,11 @@ user does not request data that far.) 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 --git a/drivers/scsi/st.c b/drivers/scsi/st.c index 4daa372ed381..8d5f8b4f9a22 100644 --- a/drivers/scsi/st.c +++ b/drivers/scsi/st.c @@ -56,7 +56,8 @@ static const char *verstr = "20101219"; /* 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 max_sg_segs; static int try_direct_io = TRY_DIRECT_IO; static int try_rdio = 1; static int try_wdio = 1; +static int debug_flag; static struct class st_sysfs_class; static const struct attribute_group *st_dev_groups[]; @@ -100,6 +102,9 @@ module_param_named(max_sg_segs, max_sg_segs, int, 0); 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 @@ static struct st_dev_parm { }, { "try_direct_io", &try_direct_io + }, + { + "debug_flag", &debug_flag } }; #endif @@ -4309,6 +4317,12 @@ static int __init init_st(void) 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"); |