[PATCH 15/20] staging/lustre/libcfs: get rid of debugfs/lnet/console_backoff

[green at linuxhacker.ru]

From: Oleg Drokin <green at linuxhacker.ru>

module parameter libcfs_console_backoff accessible through
/sys/module/libcfs/parameters/libcfs_console_backoff would
do the same thing, just add a special "uintpos" parameter
type to disallow 0 values too.
Also add a symlink to the module parameter variable for
backwards compatibility

Signed-off-by: Oleg Drokin <green at linuxhacker.ru>
---
 drivers/staging/lustre/lustre/libcfs/debug.c  | 31 +++++++++++++-
 drivers/staging/lustre/lustre/libcfs/module.c | 59 +++++++++++----------------
 2 files changed, 54 insertions(+), 36 deletions(-)

diff --git a/drivers/staging/lustre/lustre/libcfs/debug.c b/drivers/staging/lustre/lustre/libcfs/debug.c
index 021c92f..147004ce 100644
--- a/drivers/staging/lustre/lustre/libcfs/debug.c
+++ b/drivers/staging/lustre/lustre/libcfs/debug.c
@@ -82,8 +82,37 @@ module_param(libcfs_console_min_delay, uint, 0644);
 MODULE_PARM_DESC(libcfs_console_min_delay, "Lustre kernel debug console min delay (jiffies)");
 EXPORT_SYMBOL(libcfs_console_min_delay);
 
+static int param_set_uint_minmax(const char *val,
+				 const struct kernel_param *kp,
+				 unsigned int min, unsigned int max)
+{
+	unsigned int num;
+	int ret;
+
+	if (!val)
+		return -EINVAL;
+	ret = kstrtouint(val, 0, &num);
+	if (ret == -EINVAL || num < min || num > max)
+		return -EINVAL;
+	*((unsigned int *)kp->arg) = num;
+	return 0;
+}
+
+static int param_set_uintpos(const char *val, const struct kernel_param *kp)
+{
+	return param_set_uint_minmax(val, kp, 1, -1);
+}
+
+static struct kernel_param_ops param_ops_uintpos = {
+	.set = param_set_uintpos,
+	.get = param_get_uint,
+};
+
+#define param_check_uintpos(name, p) \
+		__param_check(name, p, unsigned int)
+
 unsigned int libcfs_console_backoff = CDEBUG_DEFAULT_BACKOFF;
-module_param(libcfs_console_backoff, uint, 0644);
+module_param(libcfs_console_backoff, uintpos, 0644);
 MODULE_PARM_DESC(libcfs_console_backoff, "Lustre kernel debug console backoff factor");
 EXPORT_SYMBOL(libcfs_console_backoff);
 
diff --git a/drivers/staging/lustre/lustre/libcfs/module.c b/drivers/staging/lustre/lustre/libcfs/module.c
index 8a26446..8b9ce22 100644
--- a/drivers/staging/lustre/lustre/libcfs/module.c
+++ b/drivers/staging/lustre/lustre/libcfs/module.c
@@ -678,34 +678,6 @@ static int proc_console_min_delay_cs(struct ctl_table *table, int write,
 	return rc;
 }
 
-static int proc_console_backoff(struct ctl_table *table, int write,
-				void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-	int rc, backoff;
-	struct ctl_table dummy = *table;
-
-	dummy.data = &backoff;
-	dummy.proc_handler = &proc_dointvec;
-
-	if (!write) { /* read */
-		backoff = libcfs_console_backoff;
-		rc = proc_dointvec(&dummy, write, buffer, lenp, ppos);
-		return rc;
-	}
-
-	/* write */
-	backoff = 0;
-	rc = proc_dointvec(&dummy, write, buffer, lenp, ppos);
-	if (rc < 0)
-		return rc;
-	if (backoff <= 0)
-		return -EINVAL;
-
-	libcfs_console_backoff = backoff;
-
-	return rc;
-}
-
 static int libcfs_force_lbug(struct ctl_table *table, int write,
 			     void __user *buffer,
 			     size_t *lenp, loff_t *ppos)
@@ -815,13 +787,6 @@ static struct ctl_table lnet_table[] = {
 		.proc_handler = &proc_console_min_delay_cs
 	},
 	{
-		.procname = "console_backoff",
-		.maxlen   = sizeof(int),
-		.mode     = 0644,
-		.proc_handler = &proc_console_backoff
-	},
-
-	{
 		.procname = "cpu_partition_table",
 		.maxlen   = 128,
 		.mode     = 0444,
@@ -907,6 +872,23 @@ static struct ctl_table lnet_table[] = {
 	}
 };
 
+struct lnet_debugfs_symlink_def {
+	char *name;
+	char *target;
+};
+
+struct lnet_debugfs_symlink_def lnet_debugfs_symlinks[] = {
+	{ "console_ratelimit",
+	  "/sys/module/libcfs/parameters/libcfs_console_ratelimit"},
+	{ "debug_path",
+	  "/sys/module/libcfs/parameters/libcfs_debug_file_path"},
+	{ "panic_on_lbug",
+	  "/sys/module/libcfs/parameters/libcfs_panic_on_lbug"},
+	{ "libcfs_console_backoff",
+	  "/sys/module/libcfs/parameters/libcfs_console_backoff"},
+	{},
+};
+
 static ssize_t lnet_debugfs_read(struct file *filp, char __user *buf,
 				 size_t count, loff_t *ppos)
 {
@@ -944,6 +926,7 @@ static void insert_debugfs(void)
 {
 	struct ctl_table *table;
 	struct dentry *entry;
+	struct lnet_debugfs_symlink_def *symlinks;
 
 	if (lnet_debugfs_root == NULL)
 		lnet_debugfs_root = debugfs_create_dir("lnet", NULL);
@@ -956,6 +939,12 @@ static void insert_debugfs(void)
 		entry = debugfs_create_file(table->procname, table->mode,
 					    lnet_debugfs_root, table,
 					    &lnet_debugfs_file_operations);
+
+	for (symlinks = lnet_debugfs_symlinks; symlinks->name; symlinks++)
+		entry = debugfs_create_symlink(symlinks->name,
+					       lnet_debugfs_root,
+					       symlinks->target);
+
 }
 
 static void remove_debugfs(void)
-- 
2.1.0