V4L/DVB: tvp7002.c: fix some copy-paste errors in the comments
[safe/jmp/linux-2.6] / drivers / base / node.c
index f502711..057979a 100644 (file)
 #include <linux/cpu.h>
 #include <linux/device.h>
 #include <linux/swap.h>
+#include <linux/slab.h>
+
+static struct sysdev_class_attribute *node_state_attrs[];
 
 static struct sysdev_class node_class = {
        .name = "node",
+       .attrs = node_state_attrs,
 };
 
 
@@ -162,8 +166,11 @@ static ssize_t node_read_distance(struct sys_device * dev,
        int len = 0;
        int i;
 
-       /* buf currently PAGE_SIZE, need ~4 chars per node */
-       BUILD_BUG_ON(MAX_NUMNODES*4 > PAGE_SIZE/2);
+       /*
+        * buf is currently PAGE_SIZE in length and each node needs 4 chars
+        * at the most (distance + space or newline).
+        */
+       BUILD_BUG_ON(MAX_NUMNODES * 4 > PAGE_SIZE);
 
        for_each_online_node(i)
                len += sprintf(buf + len, "%s%d", i ? " " : "", node_distance(nid, i));
@@ -177,8 +184,8 @@ static SYSDEV_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 /*
  * hugetlbfs per node attributes registration interface:
  * When/if hugetlb[fs] subsystem initializes [sometime after this module],
- * it will register its per node attributes for all nodes online at that
- * time.  It will also call register_hugetlbfs_with_node(), below, to
+ * it will register its per node attributes for all online nodes with
+ * memory.  It will also call register_hugetlbfs_with_node(), below, to
  * register its attribute registration functions with this node driver.
  * Once these hooks have been initialized, the node driver will call into
  * the hugetlb module to [un]register attributes for hot-plugged nodes.
@@ -186,10 +193,14 @@ static SYSDEV_ATTR(distance, S_IRUGO, node_read_distance, NULL);
 static node_registration_func_t __hugetlb_register_node;
 static node_registration_func_t __hugetlb_unregister_node;
 
-static inline void hugetlb_register_node(struct node *node)
+static inline bool hugetlb_register_node(struct node *node)
 {
-       if (__hugetlb_register_node)
+       if (__hugetlb_register_node &&
+                       node_state(node->sysdev.id, N_HIGH_MEMORY)) {
                __hugetlb_register_node(node);
+               return true;
+       }
+       return false;
 }
 
 static inline void hugetlb_unregister_node(struct node *node)
@@ -233,6 +244,7 @@ int register_node(struct node *node, int num, struct node *parent)
                sysdev_create_file(&node->sysdev, &attr_distance);
 
                scan_unevictable_register_node(node);
+
                hugetlb_register_node(node);
        }
        return error;
@@ -254,7 +266,7 @@ void unregister_node(struct node *node)
        sysdev_remove_file(&node->sysdev, &attr_distance);
 
        scan_unevictable_unregister_node(node);
-       hugetlb_unregister_node(node);
+       hugetlb_unregister_node(node);          /* no-op, if memoryless node */
 
        sysdev_unregister(&node->sysdev);
 }
@@ -266,26 +278,43 @@ struct node node_devices[MAX_NUMNODES];
  */
 int register_cpu_under_node(unsigned int cpu, unsigned int nid)
 {
-       if (node_online(nid)) {
-               struct sys_device *obj = get_cpu_sysdev(cpu);
-               if (!obj)
-                       return 0;
-               return sysfs_create_link(&node_devices[nid].sysdev.kobj,
-                                        &obj->kobj,
-                                        kobject_name(&obj->kobj));
-        }
+       int ret;
+       struct sys_device *obj;
 
-       return 0;
+       if (!node_online(nid))
+               return 0;
+
+       obj = get_cpu_sysdev(cpu);
+       if (!obj)
+               return 0;
+
+       ret = sysfs_create_link(&node_devices[nid].sysdev.kobj,
+                               &obj->kobj,
+                               kobject_name(&obj->kobj));
+       if (ret)
+               return ret;
+
+       return sysfs_create_link(&obj->kobj,
+                                &node_devices[nid].sysdev.kobj,
+                                kobject_name(&node_devices[nid].sysdev.kobj));
 }
 
 int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 {
-       if (node_online(nid)) {
-               struct sys_device *obj = get_cpu_sysdev(cpu);
-               if (obj)
-                       sysfs_remove_link(&node_devices[nid].sysdev.kobj,
-                                        kobject_name(&obj->kobj));
-       }
+       struct sys_device *obj;
+
+       if (!node_online(nid))
+               return 0;
+
+       obj = get_cpu_sysdev(cpu);
+       if (!obj)
+               return 0;
+
+       sysfs_remove_link(&node_devices[nid].sysdev.kobj,
+                         kobject_name(&obj->kobj));
+       sysfs_remove_link(&obj->kobj,
+                         kobject_name(&node_devices[nid].sysdev.kobj));
+
        return 0;
 }
 
@@ -307,6 +336,7 @@ static int get_nid_for_pfn(unsigned long pfn)
 /* register memory section under specified node if it spans that node */
 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 {
+       int ret;
        unsigned long pfn, sect_start_pfn, sect_end_pfn;
 
        if (!mem_blk)
@@ -323,9 +353,15 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
                        continue;
                if (page_nid != nid)
                        continue;
-               return sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
+               ret = sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
                                        &mem_blk->sysdev.kobj,
                                        kobject_name(&mem_blk->sysdev.kobj));
+               if (ret)
+                       return ret;
+
+               return sysfs_create_link_nowarn(&mem_blk->sysdev.kobj,
+                               &node_devices[nid].sysdev.kobj,
+                               kobject_name(&node_devices[nid].sysdev.kobj));
        }
        /* mem section does not span the specified node */
        return 0;
@@ -334,12 +370,16 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
 /* unregister memory section under all nodes that it spans */
 int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
 {
-       nodemask_t unlinked_nodes;
+       NODEMASK_ALLOC(nodemask_t, unlinked_nodes, GFP_KERNEL);
        unsigned long pfn, sect_start_pfn, sect_end_pfn;
 
-       if (!mem_blk)
+       if (!mem_blk) {
+               NODEMASK_FREE(unlinked_nodes);
                return -EFAULT;
-       nodes_clear(unlinked_nodes);
+       }
+       if (!unlinked_nodes)
+               return -ENOMEM;
+       nodes_clear(*unlinked_nodes);
        sect_start_pfn = section_nr_to_pfn(mem_blk->phys_index);
        sect_end_pfn = sect_start_pfn + PAGES_PER_SECTION - 1;
        for (pfn = sect_start_pfn; pfn <= sect_end_pfn; pfn++) {
@@ -350,11 +390,14 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
                        continue;
                if (!node_online(nid))
                        continue;
-               if (node_test_and_set(nid, unlinked_nodes))
+               if (node_test_and_set(nid, *unlinked_nodes))
                        continue;
                sysfs_remove_link(&node_devices[nid].sysdev.kobj,
                         kobject_name(&mem_blk->sysdev.kobj));
+               sysfs_remove_link(&mem_blk->sysdev.kobj,
+                        kobject_name(&node_devices[nid].sysdev.kobj));
        }
+       NODEMASK_FREE(unlinked_nodes);
        return 0;
 }
 
@@ -384,9 +427,77 @@ static int link_mem_sections(int nid)
        }
        return err;
 }
-#else
+
+#ifdef CONFIG_HUGETLBFS
+/*
+ * Handle per node hstate attribute [un]registration on transistions
+ * to/from memoryless state.
+ */
+static void node_hugetlb_work(struct work_struct *work)
+{
+       struct node *node = container_of(work, struct node, node_work);
+
+       /*
+        * We only get here when a node transitions to/from memoryless state.
+        * We can detect which transition occurred by examining whether the
+        * node has memory now.  hugetlb_register_node() already check this
+        * so we try to register the attributes.  If that fails, then the
+        * node has transitioned to memoryless, try to unregister the
+        * attributes.
+        */
+       if (!hugetlb_register_node(node))
+               hugetlb_unregister_node(node);
+}
+
+static void init_node_hugetlb_work(int nid)
+{
+       INIT_WORK(&node_devices[nid].node_work, node_hugetlb_work);
+}
+
+static int node_memory_callback(struct notifier_block *self,
+                               unsigned long action, void *arg)
+{
+       struct memory_notify *mnb = arg;
+       int nid = mnb->status_change_nid;
+
+       switch (action) {
+       case MEM_ONLINE:
+       case MEM_OFFLINE:
+               /*
+                * offload per node hstate [un]registration to a work thread
+                * when transitioning to/from memoryless state.
+                */
+               if (nid != NUMA_NO_NODE)
+                       schedule_work(&node_devices[nid].node_work);
+               break;
+
+       case MEM_GOING_ONLINE:
+       case MEM_GOING_OFFLINE:
+       case MEM_CANCEL_ONLINE:
+       case MEM_CANCEL_OFFLINE:
+       default:
+               break;
+       }
+
+       return NOTIFY_OK;
+}
+#endif /* CONFIG_HUGETLBFS */
+#else  /* !CONFIG_MEMORY_HOTPLUG_SPARSE */
+
 static int link_mem_sections(int nid) { return 0; }
-#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
+#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
+
+#if !defined(CONFIG_MEMORY_HOTPLUG_SPARSE) || \
+    !defined(CONFIG_HUGETLBFS)
+static inline int node_memory_callback(struct notifier_block *self,
+                               unsigned long action, void *arg)
+{
+       return NOTIFY_OK;
+}
+
+static void init_node_hugetlb_work(int nid) { }
+
+#endif
 
 int register_one_node(int nid)
 {
@@ -410,6 +521,9 @@ int register_one_node(int nid)
 
                /* link memory sections under this node */
                error = link_mem_sections(nid);
+
+               /* initialize work queue for memory hot plug */
+               init_node_hugetlb_work(nid);
        }
 
        return error;
@@ -437,75 +551,55 @@ static ssize_t print_nodes_state(enum node_states state, char *buf)
        return n;
 }
 
-static ssize_t print_nodes_possible(struct sysdev_class *class, char *buf)
-{
-       return print_nodes_state(N_POSSIBLE, buf);
-}
-
-static ssize_t print_nodes_online(struct sysdev_class *class, char *buf)
-{
-       return print_nodes_state(N_ONLINE, buf);
-}
-
-static ssize_t print_nodes_has_normal_memory(struct sysdev_class *class,
-                                               char *buf)
-{
-       return print_nodes_state(N_NORMAL_MEMORY, buf);
-}
+struct node_attr {
+       struct sysdev_class_attribute attr;
+       enum node_states state;
+};
 
-static ssize_t print_nodes_has_cpu(struct sysdev_class *class, char *buf)
+static ssize_t show_node_state(struct sysdev_class *class,
+                              struct sysdev_class_attribute *attr, char *buf)
 {
-       return print_nodes_state(N_CPU, buf);
+       struct node_attr *na = container_of(attr, struct node_attr, attr);
+       return print_nodes_state(na->state, buf);
 }
 
-static SYSDEV_CLASS_ATTR(possible, 0444, print_nodes_possible, NULL);
-static SYSDEV_CLASS_ATTR(online, 0444, print_nodes_online, NULL);
-static SYSDEV_CLASS_ATTR(has_normal_memory, 0444, print_nodes_has_normal_memory,
-                                                                       NULL);
-static SYSDEV_CLASS_ATTR(has_cpu, 0444, print_nodes_has_cpu, NULL);
+#define _NODE_ATTR(name, state) \
+       { _SYSDEV_CLASS_ATTR(name, 0444, show_node_state, NULL), state }
 
+static struct node_attr node_state_attr[] = {
+       _NODE_ATTR(possible, N_POSSIBLE),
+       _NODE_ATTR(online, N_ONLINE),
+       _NODE_ATTR(has_normal_memory, N_NORMAL_MEMORY),
+       _NODE_ATTR(has_cpu, N_CPU),
 #ifdef CONFIG_HIGHMEM
-static ssize_t print_nodes_has_high_memory(struct sysdev_class *class,
-                                                char *buf)
-{
-       return print_nodes_state(N_HIGH_MEMORY, buf);
-}
-
-static SYSDEV_CLASS_ATTR(has_high_memory, 0444, print_nodes_has_high_memory,
-                                                                        NULL);
+       _NODE_ATTR(has_high_memory, N_HIGH_MEMORY),
 #endif
+};
 
-struct sysdev_class_attribute *node_state_attr[] = {
-       &attr_possible,
-       &attr_online,
-       &attr_has_normal_memory,
+static struct sysdev_class_attribute *node_state_attrs[] = {
+       &node_state_attr[0].attr,
+       &node_state_attr[1].attr,
+       &node_state_attr[2].attr,
+       &node_state_attr[3].attr,
 #ifdef CONFIG_HIGHMEM
-       &attr_has_high_memory,
+       &node_state_attr[4].attr,
 #endif
-       &attr_has_cpu,
+       NULL
 };
 
-static int node_states_init(void)
-{
-       int i;
-       int err = 0;
-
-       for (i = 0;  i < NR_NODE_STATES; i++) {
-               int ret;
-               ret = sysdev_class_create_file(&node_class, node_state_attr[i]);
-               if (!err)
-                       err = ret;
-       }
-       return err;
-}
-
+#define NODE_CALLBACK_PRI      2       /* lower than SLAB */
 static int __init register_node_type(void)
 {
        int ret;
 
+       BUILD_BUG_ON(ARRAY_SIZE(node_state_attr) != NR_NODE_STATES);
+       BUILD_BUG_ON(ARRAY_SIZE(node_state_attrs)-1 != NR_NODE_STATES);
+
        ret = sysdev_class_register(&node_class);
-       if (!ret)
-               ret = node_states_init();
+       if (!ret) {
+               hotplug_memory_notifier(node_memory_callback,
+                                       NODE_CALLBACK_PRI);
+       }
 
        /*
         * Note:  we're not going to unregister the node class if we fail