Revert "cpusets: randomize node rotor used in cpuset_mem_spread_node()"

This reverts commit 0ac0c0d0, which
caused cross-architecture build problems for all the wrong reasons.
IA64 already added its own version of __node_random(), but the fact is,
there is nothing architectural about the function, and the original
commit was just badly done. Revert it, since no fix is forthcoming.
Requested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/mm/numa.c

@@ -2,7 +2,6 @@
 #include <linux/topology.h>
 #include <linux/module.h>
 #include <linux/bootmem.h>
-#include <linux/random.h>
 
 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
 # define DBG(x...) printk(KERN_DEBUG x)
@@ -66,19 +65,3 @@ const struct cpumask *cpumask_of_node(int node)
 }
 EXPORT_SYMBOL(cpumask_of_node);
 #endif
-
-/*
- * Return the bit number of a random bit set in the nodemask.
- *   (returns -1 if nodemask is empty)
- */
-int __node_random(const nodemask_t *maskp)
-{
-	int w, bit = -1;
-
-	w = nodes_weight(*maskp);
-	if (w)
-		bit = bitmap_ord_to_pos(maskp->bits,
-			get_random_int() % w, MAX_NUMNODES);
-	return bit;
-}
-EXPORT_SYMBOL(__node_random);

include/linux/bitmap.h

@@ -141,7 +141,6 @@ extern int bitmap_find_free_region(unsigned long *bitmap, int bits, int order);
 extern void bitmap_release_region(unsigned long *bitmap, int pos, int order);
 extern int bitmap_allocate_region(unsigned long *bitmap, int pos, int order);
 extern void bitmap_copy_le(void *dst, const unsigned long *src, int nbits);
-extern int bitmap_ord_to_pos(const unsigned long *bitmap, int n, int bits);
 
 #define BITMAP_LAST_WORD_MASK(nbits)					\
 (									\

include/linux/nodemask.h

@@ -66,8 +66,6 @@
  * int num_online_nodes()		Number of online Nodes
  * int num_possible_nodes()		Number of all possible Nodes
  *
- * int node_random(mask)		Random node with set bit in mask
- *
  * int node_online(node)		Is some node online?
  * int node_possible(node)		Is some node possible?
  *
@@ -432,10 +430,6 @@ static inline void node_set_offline(int nid)
 	node_clear_state(nid, N_ONLINE);
 	nr_online_nodes = num_node_state(N_ONLINE);
 }
-
-#define node_random(mask) __node_random(&(mask))
-extern int __node_random(const nodemask_t *maskp);
-
 #else
 
 static inline int node_state(int node, enum node_states state)
@@ -466,8 +460,6 @@ static inline int num_node_state(enum node_states state)
 
 #define node_set_online(node)	   node_set_state((node), N_ONLINE)
 #define node_set_offline(node)	   node_clear_state((node), N_ONLINE)
-
-static inline int node_random(const nodemask_t mask) { return 0; }
 #endif
 
 #define node_online_map 	node_states[N_ONLINE]

kernel/fork.c

@@ -1086,10 +1086,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
  	}
 	mpol_fix_fork_child_flag(p);
 #endif
-#ifdef CONFIG_CPUSETS
-	p->cpuset_mem_spread_rotor = node_random(p->mems_allowed);
-	p->cpuset_slab_spread_rotor = node_random(p->mems_allowed);
-#endif
 #ifdef CONFIG_TRACE_IRQFLAGS
 	p->irq_events = 0;
 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW

lib/bitmap.c

@@ -672,7 +672,7 @@ static int bitmap_pos_to_ord(const unsigned long *buf, int pos, int bits)
  *
  * The bit positions 0 through @bits are valid positions in @buf.
  */
-int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
+static int bitmap_ord_to_pos(const unsigned long *buf, int ord, int bits)
 {
 	int pos = 0;