vfs: factor sb iteration out of do_emergency_remount

The intent is to reduce code duplication with other code
iterating the list.

No functional changes.

Signed-off-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 36 insertions, 25 deletions

diff --git a/fs/super.c b/fs/super.c
index 166c4ee0d0ed..fd9c02f543eb 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -574,6 +574,28 @@ void drop_super_exclusive(struct super_block *sb)
 }
 EXPORT_SYMBOL(drop_super_exclusive);
 
+static void __iterate_supers(void (*f)(struct super_block *))
+{
+        struct super_block *sb, *p = NULL;
+
+        spin_lock(&sb_lock);
+        list_for_each_entry(sb, &super_blocks, s_list) {
+                if (hlist_unhashed(&sb->s_instances))
+                        continue;
+                sb->s_count++;
+                spin_unlock(&sb_lock);
+
+                f(sb);
+
+                spin_lock(&sb_lock);
+                if (p)
+                        __put_super(p);
+                p = sb;
+        }
+        if (p)
+                __put_super(p);
+        spin_unlock(&sb_lock);
+}
 /**
  *      iterate_supers - call function for all active superblocks
  *      @f: function to call
@@ -881,33 +903,22 @@ cancel_readonly:
         return retval;
 }
 
-static void do_emergency_remount(struct work_struct *work)
+static void do_emergency_remount_callback(struct super_block *sb)
 {
-        struct super_block *sb, *p = NULL;
-
-        spin_lock(&sb_lock);
-        list_for_each_entry(sb, &super_blocks, s_list) {
-                if (hlist_unhashed(&sb->s_instances))
-                        continue;
-                sb->s_count++;
-                spin_unlock(&sb_lock);
-                down_write(&sb->s_umount);
-                if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) &&
-                    !sb_rdonly(sb)) {
-                        /*
-                         * What lock protects sb->s_flags??
-                         */
-                        do_remount_sb(sb, SB_RDONLY, NULL, 1);
-                }
-                up_write(&sb->s_umount);
-                spin_lock(&sb_lock);
-                if (p)
-                        __put_super(p);
-                p = sb;
+        down_write(&sb->s_umount);
+        if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) &&
+            !sb_rdonly(sb)) {
+                /*
+                 * What lock protects sb->s_flags??
+                 */
+                do_remount_sb(sb, SB_RDONLY, NULL, 1);
         }
-        if (p)
-                __put_super(p);
-        spin_unlock(&sb_lock);
+        up_write(&sb->s_umount);
+}
+
+static void do_emergency_remount(struct work_struct *work)
+{
+        __iterate_supers(do_emergency_remount_callback);
         kfree(work);
         printk("Emergency Remount complete\n");
 }