st: add a debug_flag module parameter request (2bec708a) · Commits · 戴 / test

Documentation/scsi/st.txt

+5 −3

Original line number	Diff line number	Diff line
		@@ -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

drivers/scsi/st.c

+15 −1

Original line number	Diff line number	Diff line
		@@ -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");

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