sysfs, kernfs: make inode number ida per kernfs_root

kernfs is being updated to allow multiple sysfs_dirent hierarchies so
that it can also be used by other users.  Currently, inode number is
allocated using a global ida, sysfs_ino_ida; however, inos for
different hierarchies should be handled separately.

This patch makes ino allocation per kernfs_root.  sysfs_ino_ida is
replaced by kernfs_root->ino_ida and sysfs_new_dirent() is updated to
take @root and allocate ino from it.  ida_simple_get/remove() are used
instead of sysfs_ino_lock and sysfs_alloc/free_ino().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 34 deletions

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 246740a741ef..eaffa83719d5 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -21,9 +21,6 @@ DEFINE_MUTEX(sysfs_mutex);
 
 #define to_sysfs_dirent(X) rb_entry((X), struct sysfs_dirent, s_rb)
 
-static DEFINE_SPINLOCK(sysfs_ino_lock);
-static DEFINE_IDA(sysfs_ino_ida);
-
 /**
  *      sysfs_name_hash
  *      @name: Null terminated string to hash
@@ -205,32 +202,6 @@ static void sysfs_deactivate(struct sysfs_dirent *sd)
         rwsem_release(&sd->dep_map, 1, _RET_IP_);
 }
 
-static int sysfs_alloc_ino(unsigned int *pino)
-{
-        int ino, rc;
-
- retry:
-        spin_lock(&sysfs_ino_lock);
-        rc = ida_get_new_above(&sysfs_ino_ida, 1, &ino);
-        spin_unlock(&sysfs_ino_lock);
-
-        if (rc == -EAGAIN) {
-                if (ida_pre_get(&sysfs_ino_ida, GFP_KERNEL))
-                        goto retry;
-                rc = -ENOMEM;
-        }
-
-        *pino = ino;
-        return rc;
-}
-
-static void sysfs_free_ino(unsigned int ino)
-{
-        spin_lock(&sysfs_ino_lock);
-        ida_remove(&sysfs_ino_ida, ino);
-        spin_unlock(&sysfs_ino_lock);
-}
-
 /**
  * kernfs_get - get a reference count on a sysfs_dirent
  * @sd: the target sysfs_dirent
@@ -276,7 +247,7 @@ void kernfs_put(struct sysfs_dirent *sd)
                 security_release_secctx(sd->s_iattr->ia_secdata,
                                         sd->s_iattr->ia_secdata_len);
         kfree(sd->s_iattr);
-        sysfs_free_ino(sd->s_ino);
+        ida_simple_remove(&root->ino_ida, sd->s_ino);
         kmem_cache_free(sysfs_dir_cachep, sd);
 
         sd = parent_sd;
@@ -285,6 +256,7 @@ void kernfs_put(struct sysfs_dirent *sd)
                         goto repeat;
         } else {
                 /* just released the root sd, free @root too */
+                ida_destroy(&root->ino_ida);
                 kfree(root);
         }
 }
@@ -360,10 +332,12 @@ const struct dentry_operations sysfs_dentry_ops = {
         .d_release      = sysfs_dentry_release,
 };
 
-struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
+struct sysfs_dirent *sysfs_new_dirent(struct kernfs_root *root,
+                                      const char *name, umode_t mode, int type)
 {
         char *dup_name = NULL;
         struct sysfs_dirent *sd;
+        int ret;
 
         if (type & SYSFS_COPY_NAME) {
                 name = dup_name = kstrdup(name, GFP_KERNEL);
@@ -375,8 +349,10 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
         if (!sd)
                 goto err_out1;
 
-        if (sysfs_alloc_ino(&sd->s_ino))
+        ret = ida_simple_get(&root->ino_ida, 1, 0, GFP_KERNEL);
+        if (ret < 0)
                 goto err_out2;
+        sd->s_ino = ret;
 
         atomic_set(&sd->s_count, 1);
         atomic_set(&sd->s_active, 0);
@@ -628,8 +604,11 @@ struct kernfs_root *kernfs_create_root(void *priv)
         if (!root)
                 return ERR_PTR(-ENOMEM);
 
-        sd = sysfs_new_dirent("", S_IFDIR | S_IRUGO | S_IXUGO, SYSFS_DIR);
+        ida_init(&root->ino_ida);
+
+        sd = sysfs_new_dirent(root, "", S_IFDIR | S_IRUGO | S_IXUGO, SYSFS_DIR);
         if (!sd) {
+                ida_destroy(&root->ino_ida);
                 kfree(root);
                 return ERR_PTR(-ENOMEM);
         }
@@ -674,7 +653,7 @@ struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent,
         int rc;
 
         /* allocate */
-        sd = sysfs_new_dirent(name, mode, SYSFS_DIR);
+        sd = sysfs_new_dirent(kernfs_root(parent), name, mode, SYSFS_DIR);
         if (!sd)
                 return ERR_PTR(-ENOMEM);