1 files changed, 60 insertions, 22 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 699f371b9f12..5c4703d751b5 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -837,11 +837,46 @@ static inline unsigned char dt_type(struct sysfs_dirent *sd)
         return (sd->s_mode >> 12) & 15;
 }
 
+static int sysfs_dir_release(struct inode *inode, struct file *filp)
+{
+        sysfs_put(filp->private_data);
+        return 0;
+}
+
+static struct sysfs_dirent *sysfs_dir_pos(struct sysfs_dirent *parent_sd,
+        ino_t ino, struct sysfs_dirent *pos)
+{
+        if (pos) {
+                int valid = !(pos->s_flags & SYSFS_FLAG_REMOVED) &&
+                        pos->s_parent == parent_sd &&
+                        ino == pos->s_ino;
+                sysfs_put(pos);
+                if (valid)
+                        return pos;
+        }
+        pos = NULL;
+        if ((ino > 1) && (ino < INT_MAX)) {
+                pos = parent_sd->s_dir.children;
+                while (pos && (ino > pos->s_ino))
+                        pos = pos->s_sibling;
+        }
+        return pos;
+}
+
+static struct sysfs_dirent *sysfs_dir_next_pos(struct sysfs_dirent *parent_sd,
+        ino_t ino, struct sysfs_dirent *pos)
+{
+        pos = sysfs_dir_pos(parent_sd, ino, pos);
+        if (pos)
+                pos = pos->s_sibling;
+        return pos;
+}
+
 static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 {
         struct dentry *dentry = filp->f_path.dentry;
         struct sysfs_dirent * parent_sd = dentry->d_fsdata;
-        struct sysfs_dirent *pos;
+        struct sysfs_dirent *pos = filp->private_data;
         ino_t ino;
 
         if (filp->f_pos == 0) {
@@ -857,29 +892,31 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
                 if (filldir(dirent, "..", 2, filp->f_pos, ino, DT_DIR) == 0)
                         filp->f_pos++;
         }
-        if ((filp->f_pos > 1) && (filp->f_pos < INT_MAX)) {
-                mutex_lock(&sysfs_mutex);
-
-                /* Skip the dentries we have already reported */
-                pos = parent_sd->s_dir.children;
-                while (pos && (filp->f_pos > pos->s_ino))
-                        pos = pos->s_sibling;
-
-                for ( ; pos; pos = pos->s_sibling) {
-                        const char * name;
-                        int len;
-
-                        name = pos->s_name;
-                        len = strlen(name);
-                        filp->f_pos = ino = pos->s_ino;
+        mutex_lock(&sysfs_mutex);
+        for (pos = sysfs_dir_pos(parent_sd, filp->f_pos, pos);
+             pos;
+             pos = sysfs_dir_next_pos(parent_sd, filp->f_pos, pos)) {
+                const char * name;
+                unsigned int type;
+                int len, ret;
+
+                name = pos->s_name;
+                len = strlen(name);
+                ino = pos->s_ino;
+                type = dt_type(pos);
+                filp->f_pos = ino;
+                filp->private_data = sysfs_get(pos);
 
-                        if (filldir(dirent, name, len, filp->f_pos, ino,
-                                         dt_type(pos)) < 0)
-                                break;
-                }
-                if (!pos)
-                        filp->f_pos = INT_MAX;
                 mutex_unlock(&sysfs_mutex);
+                ret = filldir(dirent, name, len, filp->f_pos, ino, type);
+                mutex_lock(&sysfs_mutex);
+                if (ret < 0)
+                        break;
+        }
+        mutex_unlock(&sysfs_mutex);
+        if ((filp->f_pos > 1) && !pos) { /* EOF */
+                filp->f_pos = INT_MAX;
+                filp->private_data = NULL;
         }
         return 0;
 }
@@ -888,5 +925,6 @@ static int sysfs_readdir(struct file * filp, void * dirent, filldir_t filldir)
 const struct file_operations sysfs_dir_operations = {
         .read           = generic_read_dir,
         .readdir        = sysfs_readdir,
+        .release        = sysfs_dir_release,
         .llseek         = generic_file_llseek,
 };