5 files changed, 35 insertions, 17 deletions

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 4ca0b5c18192..b84d635567d3 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -536,8 +536,8 @@ void kernfs_put(struct kernfs_node *kn)
 			security_release_secctx(kn->iattr->ia_secdata,
 						kn->iattr->ia_secdata_len);
 		simple_xattrs_free(&kn->iattr->xattrs);
+		kmem_cache_free(kernfs_iattrs_cache, kn->iattr);
 	}
-	kfree(kn->iattr);
 	spin_lock(&kernfs_idr_lock);
 	idr_remove(&root->ino_idr, kn->id.ino);
 	spin_unlock(&kernfs_idr_lock);
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index f8d5021a652e..ae948aaa4c53 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -832,26 +832,35 @@ void kernfs_drain_open_files(struct kernfs_node *kn)
  * to see if it supports poll (Neither 'poll' nor 'select' return
  * an appropriate error code).  When in doubt, set a suitable timeout value.
  */
+__poll_t kernfs_generic_poll(struct kernfs_open_file *of, poll_table *wait)
+{
+	struct kernfs_node *kn = kernfs_dentry_node(of->file->f_path.dentry);
+	struct kernfs_open_node *on = kn->attr.open;
+
+	poll_wait(of->file, &on->poll, wait);
+
+	if (of->event != atomic_read(&on->event))
+		return DEFAULT_POLLMASK|EPOLLERR|EPOLLPRI;
+
+	return DEFAULT_POLLMASK;
+}
+
 static __poll_t kernfs_fop_poll(struct file *filp, poll_table *wait)
 {
 	struct kernfs_open_file *of = kernfs_of(filp);
 	struct kernfs_node *kn = kernfs_dentry_node(filp->f_path.dentry);
-	struct kernfs_open_node *on = kn->attr.open;
+	__poll_t ret;
 
 	if (!kernfs_get_active(kn))
-		goto trigger;
+		return DEFAULT_POLLMASK|EPOLLERR|EPOLLPRI;
 
-	poll_wait(filp, &on->poll, wait);
+	if (kn->attr.ops->poll)
+		ret = kn->attr.ops->poll(of, wait);
+	else
+		ret = kernfs_generic_poll(of, wait);
 
 	kernfs_put_active(kn);
-
-	if (of->event != atomic_read(&on->event))
-		goto trigger;
-
-	return DEFAULT_POLLMASK;
-
- trigger:
-	return DEFAULT_POLLMASK|EPOLLERR|EPOLLPRI;
+	return ret;
 }
 
 static void kernfs_notify_workfn(struct work_struct *work)
diff --git a/fs/kernfs/inode.c b/fs/kernfs/inode.c
index 80cebcd94c90..0c1fd945ce42 100644
--- a/fs/kernfs/inode.c
+++ b/fs/kernfs/inode.c
@@ -42,7 +42,7 @@ static struct kernfs_iattrs *kernfs_iattrs(struct kernfs_node *kn)
 	if (kn->iattr)
 		goto out_unlock;
 
-	kn->iattr = kzalloc(sizeof(struct kernfs_iattrs), GFP_KERNEL);
+	kn->iattr = kmem_cache_zalloc(kernfs_iattrs_cache, GFP_KERNEL);
 	if (!kn->iattr)
 		goto out_unlock;
 	iattrs = &kn->iattr->ia_iattr;
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index 3d83b114bb08..dba810cd83b1 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -78,7 +78,7 @@ static inline struct kernfs_node *kernfs_dentry_node(struct dentry *dentry)
 }
 
 extern const struct super_operations kernfs_sops;
-extern struct kmem_cache *kernfs_node_cache;
+extern struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
 
 /*
  * inode.c
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index fdf527b6d79c..f3ac352699cf 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -20,7 +20,7 @@
 
 #include "kernfs-internal.h"
 
-struct kmem_cache *kernfs_node_cache;
+struct kmem_cache *kernfs_node_cache, *kernfs_iattrs_cache;
 
 static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data)
 {
@@ -196,8 +196,10 @@ struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
 		return dentry;
 
 	knparent = find_next_ancestor(kn, NULL);
-	if (WARN_ON(!knparent))
+	if (WARN_ON(!knparent)) {
+		dput(dentry);
 		return ERR_PTR(-EINVAL);
+	}
 
 	do {
 		struct dentry *dtmp;
@@ -206,8 +208,10 @@ struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
 		if (kn == knparent)
 			return dentry;
 		kntmp = find_next_ancestor(kn, knparent);
-		if (WARN_ON(!kntmp))
+		if (WARN_ON(!kntmp)) {
+			dput(dentry);
 			return ERR_PTR(-EINVAL);
+		}
 		dtmp = lookup_one_len_unlocked(kntmp->name, dentry,
 					       strlen(kntmp->name));
 		dput(dentry);
@@ -417,4 +421,9 @@ void __init kernfs_init(void)
 					      0,
 					      SLAB_PANIC | SLAB_TYPESAFE_BY_RCU,
 					      NULL);
+
+	/* Creates slab cache for kernfs inode attributes */
+	kernfs_iattrs_cache  = kmem_cache_create("kernfs_iattrs_cache",
+					      sizeof(struct kernfs_iattrs),
+					      0, SLAB_PANIC, NULL);
 }