staging/lustre/libcfs: get rid of debugfs/lnet/debug_mb

It's just a fancy libcfs_debug_mb module parameter wrapper,
so just add debug buffer size check and resizing and the same
functionality now would be accessible via
/sys/module/libcfs/parameters/libcfs_debug_mb

Also add a symlink for backwards compatibility.
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/libcfs/debug.c

@@ -57,8 +57,42 @@ module_param(libcfs_debug, int, 0644);
 MODULE_PARM_DESC(libcfs_debug, "Lustre kernel debug mask");
 EXPORT_SYMBOL(libcfs_debug);
 
+static int libcfs_param_debug_mb_set(const char *val,
+				     const struct kernel_param *kp)
+{
+	int rc;
+	unsigned num;
+
+	rc = kstrtouint(val, 0, &num);
+	if (rc < 0)
+		return rc;
+
+	if (!*((unsigned int *)kp->arg)) {
+		*((unsigned int *)kp->arg) = num;
+		return 0;
+	}
+
+	rc = cfs_trace_set_debug_mb(num);
+
+	if (!rc)
+		*((unsigned int *)kp->arg) = cfs_trace_get_debug_mb();
+
+	return rc;
+}
+
+/* While debug_mb setting look like unsigned int, in fact
+ * it needs quite a bunch of extra processing, so we define special
+ * debugmb parameter type with corresponding methods to handle this case */
+static struct kernel_param_ops param_ops_debugmb = {
+	.set = libcfs_param_debug_mb_set,
+	.get = param_get_uint,
+};
+
+#define param_check_debugmb(name, p) \
+		__param_check(name, p, unsigned int)
+
 static unsigned int libcfs_debug_mb;
-module_param(libcfs_debug_mb, uint, 0644);
+module_param(libcfs_debug_mb, debugmb, 0644);
 MODULE_PARM_DESC(libcfs_debug_mb, "Total debug buffer size.");
 EXPORT_SYMBOL(libcfs_debug_mb);
 
@@ -437,8 +471,10 @@ int libcfs_debug_init(unsigned long bufsize)
 	}
 	rc = cfs_tracefile_init(max);
 
-	if (rc == 0)
+	if (rc == 0) {
 		libcfs_register_panic_notifier();
+		libcfs_debug_mb = cfs_trace_get_debug_mb();
+	}
 
 	return rc;
 }

drivers/staging/lustre/lustre/libcfs/module.c

@@ -550,31 +550,6 @@ static int proc_daemon_file(struct ctl_table *table, int write,
 				 __proc_daemon_file);
 }
 
-static int __proc_debug_mb(void *data, int write,
-			   loff_t pos, void __user *buffer, int nob)
-{
-	if (!write) {
-		char tmpstr[32];
-		int  len = snprintf(tmpstr, sizeof(tmpstr), "%d",
-				    cfs_trace_get_debug_mb());
-
-		if (pos >= len)
-			return 0;
-
-		return cfs_trace_copyout_string(buffer, nob, tmpstr + pos,
-		       "\n");
-	}
-
-	return cfs_trace_set_debug_mb_usrstr(buffer, nob);
-}
-
-static int proc_debug_mb(struct ctl_table *table, int write,
-			 void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-	return proc_call_handler(table->data, write, ppos, buffer, lenp,
-				 __proc_debug_mb);
-}
-
 static int proc_console_max_delay_cs(struct ctl_table *table, int write,
 				     void __user *buffer, size_t *lenp,
 				     loff_t *ppos)
@@ -789,11 +764,6 @@ static struct ctl_table lnet_table[] = {
 		.maxlen   = 256,
 		.proc_handler = &proc_daemon_file,
 	},
-	{
-		.procname = "debug_mb",
-		.mode     = 0644,
-		.proc_handler = &proc_debug_mb,
-	},
 	{
 		.procname = "force_lbug",
 		.data     = NULL,
@@ -833,6 +803,8 @@ struct lnet_debugfs_symlink_def lnet_debugfs_symlinks[] = {
 	  "/sys/module/libcfs/parameters/libcfs_panic_on_lbug"},
 	{ "libcfs_console_backoff",
 	  "/sys/module/libcfs/parameters/libcfs_console_backoff"},
+	{ "debug_mb",
+	  "/sys/module/libcfs/parameters/libcfs_debug_mb"},
 	{},
 };
 

drivers/staging/lustre/lustre/libcfs/tracefile.c

@@ -937,18 +937,6 @@ int cfs_trace_set_debug_mb(int mb)
 	return 0;
 }
 
-int cfs_trace_set_debug_mb_usrstr(void __user *usr_str, int usr_str_nob)
-{
-	char     str[32];
-	int      rc;
-
-	rc = cfs_trace_copyin_string(str, sizeof(str), usr_str, usr_str_nob);
-	if (rc < 0)
-		return rc;
-
-	return cfs_trace_set_debug_mb(simple_strtoul(str, NULL, 0));
-}
-
 int cfs_trace_get_debug_mb(void)
 {
 	int i;

drivers/staging/lustre/lustre/libcfs/tracefile.h

@@ -77,7 +77,6 @@ int cfs_trace_dump_debug_buffer_usrstr(void __user *usr_str, int usr_str_nob);
 int cfs_trace_daemon_command(char *str);
 int cfs_trace_daemon_command_usrstr(void __user *usr_str, int usr_str_nob);
 int cfs_trace_set_debug_mb(int mb);
-int cfs_trace_set_debug_mb_usrstr(void __user *usr_str, int usr_str_nob);
 int cfs_trace_get_debug_mb(void);
 
 extern void libcfs_debug_dumplog_internal(void *arg);