6 files changed, 53 insertions, 30 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 dbf5bc250bfd..ae948aaa4c53 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -832,32 +832,40 @@ 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)
 {
 	struct kernfs_node *kn;
-	struct kernfs_open_node *on;
 	struct kernfs_super_info *info;
 repeat:
 	/* pop one off the notify_list */
@@ -871,17 +879,6 @@ repeat:
 	kn->attr.notify_next = NULL;
 	spin_unlock_irq(&kernfs_notify_lock);
 
-	/* kick poll */
-	spin_lock_irq(&kernfs_open_node_lock);
-
-	on = kn->attr.open;
-	if (on) {
-		atomic_inc(&on->event);
-		wake_up_interruptible(&on->poll);
-	}
-
-	spin_unlock_irq(&kernfs_open_node_lock);
-
 	/* kick fsnotify */
 	mutex_lock(&kernfs_mutex);
 
@@ -934,10 +931,21 @@ void kernfs_notify(struct kernfs_node *kn)
 {
 	static DECLARE_WORK(kernfs_notify_work, kernfs_notify_workfn);
 	unsigned long flags;
+	struct kernfs_open_node *on;
 
 	if (WARN_ON(kernfs_type(kn) != KERNFS_FILE))
 		return;
 
+	/* kick poll immediately */
+	spin_lock_irqsave(&kernfs_open_node_lock, flags);
+	on = kn->attr.open;
+	if (on) {
+		atomic_inc(&on->event);
+		wake_up_interruptible(&on->poll);
+	}
+	spin_unlock_irqrestore(&kernfs_open_node_lock, flags);
+
+	/* schedule work to kick fsnotify */
 	spin_lock_irqsave(&kernfs_notify_lock, flags);
 	if (!kn->attr.notify_next) {
 		kernfs_get(kn);
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 ff2716f9322e..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);
@@ -236,6 +240,9 @@ static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
 		sb->s_export_op = &kernfs_export_ops;
 	sb->s_time_gran = 1;
 
+	/* sysfs dentries and inodes don't require IO to create */
+	sb->s_shrink.seeks = 0;
+
 	/* get root inode, initialize and unlock it */
 	mutex_lock(&kernfs_mutex);
 	inode = kernfs_get_inode(sb, info->root->kn);
@@ -414,4 +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);
 }
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 305b220af45d..162f43b80c84 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -72,6 +72,9 @@ static int kernfs_get_target_path(struct kernfs_node *parent,
 		if (base == kn)
 			break;
 
+		if ((s - path) + 3 >= PATH_MAX)
+			return -ENAMETOOLONG;
+
 		strcpy(s, "../");
 		s += 3;
 		base = base->parent;
@@ -88,7 +91,7 @@ static int kernfs_get_target_path(struct kernfs_node *parent,
 	if (len < 2)
 		return -EINVAL;
 	len--;
-	if ((s - path) + len > PATH_MAX)
+	if ((s - path) + len >= PATH_MAX)
 		return -ENAMETOOLONG;
 
 	/* reverse fillup of target string from target to base */