Merge tag 'driver-core-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core / sysfs patches from Greg KH:
 "Here's the big driver core and sysfs patch set for 3.14-rc1.

  There's a lot of work here moving sysfs logic out into a "kernfs" to
  allow other subsystems to also have a virtual filesystem with the same
  attributes of sysfs (handle device disconnect, dynamic creation /
  removal as needed / unneeded, etc)

  This is primarily being done for the cgroups filesystem, but the goal
  is to also move debugfs to it when it is ready, solving all of the
  known issues in that filesystem as well.  The code isn't completed
  yet, but all should be stable now (there is a big section that was
  reverted due to problems found when testing)

  There's also some other smaller fixes, and a driver core addition that
  allows for a "collection" of objects, that the DRM people will be
  using soon (it's in this tree to make merges after -rc1 easier)

  All of this has been in linux-next with no reported issues"

* tag 'driver-core-3.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (113 commits)
  kernfs: associate a new kernfs_node with its parent on creation
  kernfs: add struct dentry declaration in kernfs.h
  kernfs: fix get_active failure handling in kernfs_seq_*()
  Revert "kernfs: fix get_active failure handling in kernfs_seq_*()"
  Revert "kernfs: replace kernfs_node->u.completion with kernfs_root->deactivate_waitq"
  Revert "kernfs: remove KERNFS_ACTIVE_REF and add kernfs_lockdep()"
  Revert "kernfs: remove KERNFS_REMOVED"
  Revert "kernfs: restructure removal path to fix possible premature return"
  Revert "kernfs: invoke kernfs_unmap_bin_file() directly from __kernfs_remove()"
  Revert "kernfs: remove kernfs_addrm_cxt"
  Revert "kernfs: make kernfs_get_active() block if the node is deactivated but not removed"
  Revert "kernfs: implement kernfs_{de|re}activate[_self]()"
  Revert "kernfs, sysfs, driver-core: implement kernfs_remove_self() and its wrappers"
  Revert "pci: use device_remove_file_self() instead of device_schedule_callback()"
  Revert "scsi: use device_remove_file_self() instead of device_schedule_callback()"
  Revert "s390: use device_remove_file_self() instead of device_schedule_callback()"
  Revert "sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()"
  Revert "kernfs: remove unnecessary NULL check in __kernfs_remove()"
  kernfs: remove unnecessary NULL check in __kernfs_remove()
  drivers/base: provide an infrastructure for componentised subsystems
  ...

1 files changed, 151 insertions, 0 deletions

diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
new file mode 100644
index 00000000000..4d457055acb
--- /dev/null
+++ b/fs/kernfs/symlink.c
@@ -0,0 +1,151 @@
+/*
+ * fs/kernfs/symlink.c - kernfs symlink implementation
+ *
+ * Copyright (c) 2001-3 Patrick Mochel
+ * Copyright (c) 2007 SUSE Linux Products GmbH
+ * Copyright (c) 2007, 2013 Tejun Heo <tj@kernel.org>
+ *
+ * This file is released under the GPLv2.
+ */
+
+#include <linux/fs.h>
+#include <linux/gfp.h>
+#include <linux/namei.h>
+
+#include "kernfs-internal.h"
+
+/**
+ * kernfs_create_link - create a symlink
+ * @parent: directory to create the symlink in
+ * @name: name of the symlink
+ * @target: target node for the symlink to point to
+ *
+ * Returns the created node on success, ERR_PTR() value on error.
+ */
+struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
+				       const char *name,
+				       struct kernfs_node *target)
+{
+	struct kernfs_node *kn;
+	struct kernfs_addrm_cxt acxt;
+	int error;
+
+	kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK);
+	if (!kn)
+		return ERR_PTR(-ENOMEM);
+
+	if (kernfs_ns_enabled(parent))
+		kn->ns = target->ns;
+	kn->symlink.target_kn = target;
+	kernfs_get(target);	/* ref owned by symlink */
+
+	kernfs_addrm_start(&acxt);
+	error = kernfs_add_one(&acxt, kn);
+	kernfs_addrm_finish(&acxt);
+
+	if (!error)
+		return kn;
+
+	kernfs_put(kn);
+	return ERR_PTR(error);
+}
+
+static int kernfs_get_target_path(struct kernfs_node *parent,
+				  struct kernfs_node *target, char *path)
+{
+	struct kernfs_node *base, *kn;
+	char *s = path;
+	int len = 0;
+
+	/* go up to the root, stop at the base */
+	base = parent;
+	while (base->parent) {
+		kn = target->parent;
+		while (kn->parent && base != kn)
+			kn = kn->parent;
+
+		if (base == kn)
+			break;
+
+		strcpy(s, "../");
+		s += 3;
+		base = base->parent;
+	}
+
+	/* determine end of target string for reverse fillup */
+	kn = target;
+	while (kn->parent && kn != base) {
+		len += strlen(kn->name) + 1;
+		kn = kn->parent;
+	}
+
+	/* check limits */
+	if (len < 2)
+		return -EINVAL;
+	len--;
+	if ((s - path) + len > PATH_MAX)
+		return -ENAMETOOLONG;
+
+	/* reverse fillup of target string from target to base */
+	kn = target;
+	while (kn->parent && kn != base) {
+		int slen = strlen(kn->name);
+
+		len -= slen;
+		strncpy(s + len, kn->name, slen);
+		if (len)
+			s[--len] = '/';
+
+		kn = kn->parent;
+	}
+
+	return 0;
+}
+
+static int kernfs_getlink(struct dentry *dentry, char *path)
+{
+	struct kernfs_node *kn = dentry->d_fsdata;
+	struct kernfs_node *parent = kn->parent;
+	struct kernfs_node *target = kn->symlink.target_kn;
+	int error;
+
+	mutex_lock(&kernfs_mutex);
+	error = kernfs_get_target_path(parent, target, path);
+	mutex_unlock(&kernfs_mutex);
+
+	return error;
+}
+
+static void *kernfs_iop_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+	int error = -ENOMEM;
+	unsigned long page = get_zeroed_page(GFP_KERNEL);
+	if (page) {
+		error = kernfs_getlink(dentry, (char *) page);
+		if (error < 0)
+			free_page((unsigned long)page);
+	}
+	nd_set_link(nd, error ? ERR_PTR(error) : (char *)page);
+	return NULL;
+}
+
+static void kernfs_iop_put_link(struct dentry *dentry, struct nameidata *nd,
+				void *cookie)
+{
+	char *page = nd_get_link(nd);
+	if (!IS_ERR(page))
+		free_page((unsigned long)page);
+}
+
+const struct inode_operations kernfs_symlink_iops = {
+	.setxattr	= kernfs_iop_setxattr,
+	.removexattr	= kernfs_iop_removexattr,
+	.getxattr	= kernfs_iop_getxattr,
+	.listxattr	= kernfs_iop_listxattr,
+	.readlink	= generic_readlink,
+	.follow_link	= kernfs_iop_follow_link,
+	.put_link	= kernfs_iop_put_link,
+	.setattr	= kernfs_iop_setattr,
+	.getattr	= kernfs_iop_getattr,
+	.permission	= kernfs_iop_permission,
+};