1 files changed, 21 insertions, 41 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 71cb253368cb..4cc19f6ab6c6 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1125,7 +1125,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
         tmp = *from;
         while (!nodes_empty(tmp)) {
                 int s,d;
-                int source = -1;
+                int source = NUMA_NO_NODE;
                 int dest = 0;
 
                 for_each_node_mask(s, tmp) {
@@ -1160,7 +1160,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
                         if (!node_isset(dest, tmp))
                                 break;
                 }
-                if (source == -1)
+                if (source == NUMA_NO_NODE)
                         break;
 
                 node_clear(source, tmp);
@@ -1835,7 +1835,7 @@ static unsigned offset_il_node(struct mempolicy *pol,
         unsigned nnodes = nodes_weight(pol->v.nodes);
         unsigned target;
         int c;
-        int nid = -1;
+        int nid = NUMA_NO_NODE;
 
         if (!nnodes)
                 return numa_node_id();
@@ -1872,11 +1872,11 @@ static inline unsigned interleave_nid(struct mempolicy *pol,
 
 /*
  * Return the bit number of a random bit set in the nodemask.
- * (returns -1 if nodemask is empty)
+ * (returns NUMA_NO_NODE if nodemask is empty)
  */
 int node_random(const nodemask_t *maskp)
 {
-        int w, bit = -1;
+        int w, bit = NUMA_NO_NODE;
 
         w = nodes_weight(*maskp);
         if (w)
@@ -2914,62 +2914,45 @@ out:
  * @maxlen:  length of @buffer
  * @pol:  pointer to mempolicy to be formatted
  *
- * Convert a mempolicy into a string.
- * Returns the number of characters in buffer (if positive)
- * or an error (negative)
+ * Convert @pol into a string.  If @buffer is too short, truncate the string.
+ * Recommend a @maxlen of at least 32 for the longest mode, "interleave", the
+ * longest flag, "relative", and to display at least a few node ids.
  */
-int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
+void mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
 {
         char *p = buffer;
-        int l;
-        nodemask_t nodes;
-        unsigned short mode;
-        unsigned short flags = pol ? pol->flags : 0;
-
-        /*
-         * Sanity check:  room for longest mode, flag and some nodes
-         */
-        VM_BUG_ON(maxlen < strlen("interleave") + strlen("relative") + 16);
+        nodemask_t nodes = NODE_MASK_NONE;
+        unsigned short mode = MPOL_DEFAULT;
+        unsigned short flags = 0;
 
-        if (!pol || pol == &default_policy)
-                mode = MPOL_DEFAULT;
-        else
+        if (pol && pol != &default_policy) {
                 mode = pol->mode;
+                flags = pol->flags;
+        }
 
         switch (mode) {
         case MPOL_DEFAULT:
-                nodes_clear(nodes);
                 break;
-
         case MPOL_PREFERRED:
-                nodes_clear(nodes);
                 if (flags & MPOL_F_LOCAL)
                         mode = MPOL_LOCAL;
                 else
                         node_set(pol->v.preferred_node, nodes);
                 break;
-
         case MPOL_BIND:
-                /* Fall through */
         case MPOL_INTERLEAVE:
                 nodes = pol->v.nodes;
                 break;
-
         default:
-                return -EINVAL;
+                WARN_ON_ONCE(1);
+                snprintf(p, maxlen, "unknown");
+                return;
         }
 
-        l = strlen(policy_modes[mode]);
-        if (buffer + maxlen < p + l + 1)
-                return -ENOSPC;
-
-        strcpy(p, policy_modes[mode]);
-        p += l;
+        p += snprintf(p, maxlen, policy_modes[mode]);
 
         if (flags & MPOL_MODE_FLAGS) {
-                if (buffer + maxlen < p + 2)
-                        return -ENOSPC;
-                *p++ = '=';
+                p += snprintf(p, buffer + maxlen - p, "=");
 
                 /*
                  * Currently, the only defined flags are mutually exclusive
@@ -2981,10 +2964,7 @@ int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol)
         }
 
         if (!nodes_empty(nodes)) {
-                if (buffer + maxlen < p + 2)
-                        return -ENOSPC;
-                *p++ = ':';
+                p += snprintf(p, buffer + maxlen - p, ":");
                 p += nodelist_scnprintf(p, buffer + maxlen - p, nodes);
         }
-        return p - buffer;
 }