Convert from a string to memory policy

This conversion function can only be called in the context of a task.
FIXME: if the contextualization would be done somwhere else then mpol_to_str
would be more useful.

Syntax of textual representation:

default
preferred=<nodenumber>
bind=<nodelist>
interleave=<nodelist>

Signed-off-by: Christoph Lameter <christoph@lameter.com>

Index: linux-2.6.13-rc6/include/linux/mempolicy.h
===================================================================
--- linux-2.6.13-rc6.orig/include/linux/mempolicy.h	2005-08-15 10:48:52.000000000 -0700
+++ linux-2.6.13-rc6/include/linux/mempolicy.h	2005-08-15 10:48:56.000000000 -0700
@@ -155,6 +155,7 @@ extern void numa_policy_init(void);
 
 /* Conversion functions */
 int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol);
+struct mempolicy *str_to_mpol(char *buffer);
 
 #else
 
Index: linux-2.6.13-rc6/mm/mempolicy.c
===================================================================
--- linux-2.6.13-rc6.orig/mm/mempolicy.c	2005-08-15 10:48:52.000000000 -0700
+++ linux-2.6.13-rc6/mm/mempolicy.c	2005-08-15 10:57:14.000000000 -0700
@@ -1288,3 +1288,38 @@ int mpol_to_str(char *buffer, int maxlen
 	return p - buffer;
 }
 
+/*
+ * Convert a representation of a memory policy from text
+ * form to binary. This can only be done from the tasks that
+ * is using the memory policy since the nodes used by a policy
+ * may be restricted by the cpuset.
+ *
+ * Returns either a memory policy or NULL for error.
+ */
+struct mempolicy *str_to_mpol(char *buffer)
+{
+	nodemask_t nodes;
+	int mode;
+	int l;
+
+	for (mode = 0; mode <= MPOL_MAX; mode++) {
+		l = strlen(policy_types[mode]);
+		if (strnicmp(policy_types[mode], buffer, l)
+			&& (mode == MPOL_DEFAULT || buffer[l] == '='))
+				break;
+	}
+
+	if (mode > MPOL_MAX)
+		return NULL;
+
+	if (mode == MPOL_DEFAULT)
+		return &default_policy;
+
+	if (nodelist_parse(buffer + l + 1, nodes) || nodes_empty(nodes))
+		return NULL;
+
+	if (!contextualize_policy(mode, &nodes))
+		return NULL;
+
+	return mpol_new(mode, &nodes);
+}