+
+#ifdef CONFIG_TMPFS
+/**
+ * mpol_parse_str - parse string to mempolicy
+ * @str: string containing mempolicy to parse
+ * @mpol: pointer to struct mempolicy pointer, returned on success.
+ * @no_context: flag whether to "contextualize" the mempolicy
+ *
+ * Format of input:
+ * <mode>[=<flags>][:<nodelist>]
+ *
+ * if @no_context is true, save the input nodemask in w.user_nodemask in
+ * the returned mempolicy. This will be used to "clone" the mempolicy in
+ * a specific context [cpuset] at a later time. Used to parse tmpfs mpol
+ * mount option. Note that if 'static' or 'relative' mode flags were
+ * specified, the input nodemask will already have been saved. Saving
+ * it again is redundant, but safe.
+ *
+ * On success, returns 0, else 1
+ */
+int mpol_parse_str(char *str, struct mempolicy **mpol, int no_context)
+{
+ struct mempolicy *new = NULL;
+ unsigned short uninitialized_var(mode);
+ unsigned short uninitialized_var(mode_flags);
+ nodemask_t nodes;
+ char *nodelist = strchr(str, ':');
+ char *flags = strchr(str, '=');
+ int i;
+ int err = 1;
+
+ if (nodelist) {
+ /* NUL-terminate mode or flags string */
+ *nodelist++ = '\0';
+ if (nodelist_parse(nodelist, nodes))
+ goto out;
+ if (!nodes_subset(nodes, node_states[N_HIGH_MEMORY]))
+ goto out;
+ } else
+ nodes_clear(nodes);
+
+ if (flags)
+ *flags++ = '\0'; /* terminate mode string */
+
+ for (i = 0; i <= MPOL_LOCAL; i++) {
+ if (!strcmp(str, policy_types[i])) {
+ mode = i;
+ break;
+ }
+ }
+ if (i > MPOL_LOCAL)
+ goto out;
+
+ switch (mode) {
+ case MPOL_PREFERRED:
+ /*
+ * Insist on a nodelist of one node only
+ */
+ if (nodelist) {
+ char *rest = nodelist;
+ while (isdigit(*rest))
+ rest++;
+ if (!*rest)
+ err = 0;
+ }
+ break;
+ case MPOL_INTERLEAVE:
+ /*
+ * Default to online nodes with memory if no nodelist
+ */
+ if (!nodelist)
+ nodes = node_states[N_HIGH_MEMORY];
+ err = 0;
+ break;
+ case MPOL_LOCAL:
+ /*
+ * Don't allow a nodelist; mpol_new() checks flags
+ */
+ if (nodelist)
+ goto out;
+ mode = MPOL_PREFERRED;
+ break;
+
+ /*
+ * case MPOL_BIND: mpol_new() enforces non-empty nodemask.
+ * case MPOL_DEFAULT: mpol_new() enforces empty nodemask, ignores flags.
+ */
+ }
+
+ mode_flags = 0;
+ if (flags) {
+ /*
+ * Currently, we only support two mutually exclusive
+ * mode flags.
+ */
+ if (!strcmp(flags, "static"))
+ mode_flags |= MPOL_F_STATIC_NODES;
+ else if (!strcmp(flags, "relative"))
+ mode_flags |= MPOL_F_RELATIVE_NODES;
+ else
+ err = 1;
+ }
+
+ new = mpol_new(mode, mode_flags, &nodes);
+ if (IS_ERR(new))
+ err = 1;
+ else if (no_context)
+ new->w.user_nodemask = nodes; /* save for contextualization */
+
+out:
+ /* Restore string for error message */
+ if (nodelist)
+ *--nodelist = ':';
+ if (flags)
+ *--flags = '=';
+ if (!err)
+ *mpol = new;
+ return err;
+}
+#endif /* CONFIG_TMPFS */
+
+/**
+ * mpol_to_str - format a mempolicy structure for printing
+ * @buffer: to contain formatted mempolicy string
+ * @maxlen: length of @buffer
+ * @pol: pointer to mempolicy to be formatted
+ * @no_context: "context free" mempolicy - use nodemask in w.user_nodemask
+ *