dm table: share target argument parsing functions

Move multipath target argument parsing code into dm-table so other
targets can share it.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 03516c7f5be1..259ce99302fc 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -797,6 +797,63 @@ int dm_table_add_target(struct dm_table *t, const char *type,
         return r;
 }
 
+/*
+ * Target argument parsing helpers.
+ */
+static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+                             unsigned *value, char **error, unsigned grouped)
+{
+        const char *arg_str = dm_shift_arg(arg_set);
+
+        if (!arg_str ||
+            (sscanf(arg_str, "%u", value) != 1) ||
+            (*value < arg->min) ||
+            (*value > arg->max) ||
+            (grouped && arg_set->argc < *value)) {
+                *error = arg->error;
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+                unsigned *value, char **error)
+{
+        return validate_next_arg(arg, arg_set, value, error, 0);
+}
+EXPORT_SYMBOL(dm_read_arg);
+
+int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
+                      unsigned *value, char **error)
+{
+        return validate_next_arg(arg, arg_set, value, error, 1);
+}
+EXPORT_SYMBOL(dm_read_arg_group);
+
+const char *dm_shift_arg(struct dm_arg_set *as)
+{
+        char *r;
+
+        if (as->argc) {
+                as->argc--;
+                r = *as->argv;
+                as->argv++;
+                return r;
+        }
+
+        return NULL;
+}
+EXPORT_SYMBOL(dm_shift_arg);
+
+void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
+{
+        BUG_ON(as->argc < num_args);
+        as->argc -= num_args;
+        as->argv += num_args;
+}
+EXPORT_SYMBOL(dm_consume_args);
+
 static int dm_table_set_type(struct dm_table *t)
 {
         unsigned i;