[PATCH] cpuset memory spread: slab cache filesystems

[pandora-kernel.git] / block / genhd.c

diff --git a/block/genhd.c b/block/genhd.c
index f1ed83f..64510fd 100644 (file)
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -15,12 +15,13 @@
 #include <linux/kmod.h>
 #include <linux/kobj_map.h>
 #include <linux/buffer_head.h>
+#include <linux/mutex.h>
 
 #define MAX_PROBE_HASH 255     /* random */
 
 static struct subsystem block_subsys;
 
-static DECLARE_MUTEX(block_subsys_sem);
+static DEFINE_MUTEX(block_subsys_lock);
 
 /*
  * Can be deleted altogether. Later.
@@ -38,41 +39,107 @@ static inline int major_to_index(int major)
        return major % MAX_PROBE_HASH;
 }
 
-#ifdef CONFIG_PROC_FS
-/* get block device names in somewhat random order */
-int get_blkdev_list(char *p, int used)
+struct blkdev_info {
+        int index;
+        struct blk_major_name *bd;
+};
+
+/*
+ * iterate over a list of blkdev_info structures.  allows
+ * the major_names array to be iterated over from outside this file
+ * must be called with the block_subsys_lock held
+ */
+void *get_next_blkdev(void *dev)
+{
+        struct blkdev_info *info;
+
+        if (dev == NULL) {
+                info = kmalloc(sizeof(*info), GFP_KERNEL);
+                if (!info)
+                        goto out;
+                info->index=0;
+                info->bd = major_names[info->index];
+                if (info->bd)
+                        goto out;
+        } else {
+                info = dev;
+        }
+
+        while (info->index < ARRAY_SIZE(major_names)) {
+                if (info->bd)
+                        info->bd = info->bd->next;
+                if (info->bd)
+                        goto out;
+                /*
+                 * No devices on this chain, move to the next
+                 */
+                info->index++;
+                info->bd = (info->index < ARRAY_SIZE(major_names)) ?
+                       major_names[info->index] : NULL;
+                if (info->bd)
+                        goto out;
+        }
+
+out:
+        return info;
+}
+
+void *acquire_blkdev_list(void)
+{
+        mutex_lock(&block_subsys_lock);
+        return get_next_blkdev(NULL);
+}
+
+void release_blkdev_list(void *dev)
+{
+        mutex_unlock(&block_subsys_lock);
+        kfree(dev);
+}
+
+
+/*
+ * Count the number of records in the blkdev_list.
+ * must be called with the block_subsys_lock held
+ */
+int count_blkdev_list(void)
 {
        struct blk_major_name *n;
-       int i, len;
+       int i, count;
 
-       len = snprintf(p, (PAGE_SIZE-used), "\nBlock devices:\n");
+       count = 0;
 
-       down(&block_subsys_sem);
        for (i = 0; i < ARRAY_SIZE(major_names); i++) {
-               for (n = major_names[i]; n; n = n->next) {
-                       /*
-                        * If the curent string plus the 5 extra characters
-                        * in the line would run us off the page, then we're done
-                        */
-                       if ((len + used + strlen(n->name) + 5) >= PAGE_SIZE)
-                               goto page_full;
-                       len += sprintf(p+len, "%3d %s\n",
-                                      n->major, n->name);
-               }
+               for (n = major_names[i]; n; n = n->next)
+                               count++;
        }
-page_full:
-       up(&block_subsys_sem);
 
-       return len;
+       return count;
 }
-#endif
+
+/*
+ * extract the major and name values from a blkdev_info struct
+ * passed in as a void to *dev.  Must be called with
+ * block_subsys_lock held
+ */
+int get_blkdev_info(void *dev, int *major, char **name)
+{
+        struct blkdev_info *info = dev;
+
+        if (info->bd == NULL)
+                return 1;
+
+        *major = info->bd->major;
+        *name = info->bd->name;
+        return 0;
+}
+
 
 int register_blkdev(unsigned int major, const char *name)
 {
        struct blk_major_name **n, *p;
        int index, ret = 0;
 
-       down(&block_subsys_sem);
+       mutex_lock(&block_subsys_lock);
 
        /* temporary */
        if (major == 0) {
@@ -117,7 +184,7 @@ int register_blkdev(unsigned int major, const char *name)
                kfree(p);
        }
 out:
-       up(&block_subsys_sem);
+       mutex_unlock(&block_subsys_lock);
        return ret;
 }
 
@@ -131,7 +198,7 @@ int unregister_blkdev(unsigned int major, const char *name)
        int index = major_to_index(major);
        int ret = 0;
 
-       down(&block_subsys_sem);
+       mutex_lock(&block_subsys_lock);
        for (n = &major_names[index]; *n; n = &(*n)->next)
                if ((*n)->major == major)
                        break;
@@ -141,7 +208,7 @@ int unregister_blkdev(unsigned int major, const char *name)
                p = *n;
                *n = p->next;
        }
-       up(&block_subsys_sem);
+       mutex_unlock(&block_subsys_lock);
        kfree(p);
 
        return ret;
@@ -235,7 +302,7 @@ static void *part_start(struct seq_file *part, loff_t *pos)
        struct list_head *p;
        loff_t l = *pos;
 
-       down(&block_subsys_sem);
+       mutex_lock(&block_subsys_lock);
        list_for_each(p, &block_subsys.kset.list)
                if (!l--)
                        return list_entry(p, struct gendisk, kobj.entry);
@@ -252,7 +319,7 @@ static void *part_next(struct seq_file *part, void *v, loff_t *pos)
 
 static void part_stop(struct seq_file *part, void *v)
 {
-       up(&block_subsys_sem);
+       mutex_unlock(&block_subsys_lock);
 }
 
 static int show_partition(struct seq_file *part, void *v)
@@ -311,7 +378,7 @@ static struct kobject *base_probe(dev_t dev, int *part, void *data)
 
 static int __init genhd_device_init(void)
 {
-       bdev_map = kobj_map_init(base_probe, &block_subsys_sem);
+       bdev_map = kobj_map_init(base_probe, &block_subsys_lock);
        blk_dev_init();
        subsystem_register(&block_subsys);
        return 0;
@@ -545,7 +612,7 @@ static void *diskstats_start(struct seq_file *part, loff_t *pos)
        loff_t k = *pos;
        struct list_head *p;
 
-       down(&block_subsys_sem);
+       mutex_lock(&block_subsys_lock);
        list_for_each(p, &block_subsys.kset.list)
                if (!k--)
                        return list_entry(p, struct gendisk, kobj.entry);
@@ -562,7 +629,7 @@ static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
 
 static void diskstats_stop(struct seq_file *part, void *v)
 {
-       up(&block_subsys_sem);
+       mutex_unlock(&block_subsys_lock);
 }
 
 static int diskstats_show(struct seq_file *s, void *v)