kernfs: remove kernfs_addrm_cxt
kernfs_addrm_cxt and the accompanying kernfs_addrm_start/finish() were added because there were operations which should be performed outside kernfs_mutex after adding and removing kernfs_nodes. The necessary operations were recorded in kernfs_addrm_cxt and performed by kernfs_addrm_finish(); however, after the recent changes which relocated deactivation and unmapping so that they're performed directly during removal, the only operation kernfs_addrm_finish() performs is kernfs_put(), which can be moved inside the removal path too. This patch moves the kernfs_put() of the base ref to __kernfs_remove() and remove kernfs_addrm_cxt and kernfs_addrm_start/finish(). * kernfs_add_one() is updated to grab and release kernfs_mutex itself. sysfs_addrm_start/finish() invocations around it are removed from all users. * __kernfs_remove() puts an unlinked node directly instead of chaining it to kernfs_addrm_cxt. Its callers are updated to grab and release kernfs_mutex instead of calling kernfs_addrm_start/finish() around it. v2: Rebased on top of "kernfs: associate a new kernfs_node with its parent on creation" which dropped @parent from kernfs_add_one(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
ccf02aaf81
commit
988cd7afb3
5 changed files with 28 additions and 108 deletions
109
fs/kernfs/dir.c
109
fs/kernfs/dir.c
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@ -395,70 +395,45 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
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return kn;
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}
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/**
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* kernfs_addrm_start - prepare for kernfs_node add/remove
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* @acxt: pointer to kernfs_addrm_cxt to be used
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*
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* This function is called when the caller is about to add or remove
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* kernfs_node. This function acquires kernfs_mutex. @acxt is used
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* to keep and pass context to other addrm functions.
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*
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* LOCKING:
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* Kernel thread context (may sleep). kernfs_mutex is locked on
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* return.
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*/
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void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt)
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__acquires(kernfs_mutex)
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{
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memset(acxt, 0, sizeof(*acxt));
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mutex_lock(&kernfs_mutex);
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}
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/**
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* kernfs_add_one - add kernfs_node to parent without warning
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* @acxt: addrm context to use
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* @kn: kernfs_node to be added
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*
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* The caller must already have initialized @kn->parent. This
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* function increments nlink of the parent's inode if @kn is a
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* directory and link into the children list of the parent.
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*
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* This function should be called between calls to
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* kernfs_addrm_start() and kernfs_addrm_finish() and should be passed
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* the same @acxt as passed to kernfs_addrm_start().
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*
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* LOCKING:
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* Determined by kernfs_addrm_start().
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*
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* RETURNS:
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* 0 on success, -EEXIST if entry with the given name already
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* exists.
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*/
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int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
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int kernfs_add_one(struct kernfs_node *kn)
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{
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struct kernfs_node *parent = kn->parent;
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bool has_ns = kernfs_ns_enabled(parent);
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struct kernfs_iattrs *ps_iattr;
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bool has_ns;
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int ret;
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if (has_ns != (bool)kn->ns) {
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WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
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has_ns ? "required" : "invalid", parent->name, kn->name);
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return -EINVAL;
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}
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mutex_lock(&kernfs_mutex);
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ret = -EINVAL;
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has_ns = kernfs_ns_enabled(parent);
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if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
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has_ns ? "required" : "invalid", parent->name, kn->name))
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goto out_unlock;
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if (kernfs_type(parent) != KERNFS_DIR)
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return -EINVAL;
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goto out_unlock;
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ret = -ENOENT;
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if (parent->flags & KERNFS_REMOVED)
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return -ENOENT;
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goto out_unlock;
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kn->hash = kernfs_name_hash(kn->name, kn->ns);
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ret = kernfs_link_sibling(kn);
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if (ret)
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return ret;
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goto out_unlock;
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/* Update timestamps on the parent */
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ps_iattr = parent->iattr;
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@ -469,35 +444,10 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
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/* Mark the entry added into directory tree */
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kn->flags &= ~KERNFS_REMOVED;
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return 0;
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}
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/**
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* kernfs_addrm_finish - finish up kernfs_node add/remove
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* @acxt: addrm context to finish up
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*
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* Finish up kernfs_node add/remove. Resources acquired by
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* kernfs_addrm_start() are released and removed kernfs_nodes are
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* cleaned up.
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*
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* LOCKING:
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* kernfs_mutex is released.
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*/
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void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
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__releases(kernfs_mutex)
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{
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/* release resources acquired by kernfs_addrm_start() */
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ret = 0;
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out_unlock:
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mutex_unlock(&kernfs_mutex);
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/* kill removed kernfs_nodes */
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while (acxt->removed) {
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struct kernfs_node *kn = acxt->removed;
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acxt->removed = kn->u.removed_list;
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kernfs_put(kn);
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}
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return ret;
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}
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/**
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@ -630,7 +580,6 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
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const char *name, umode_t mode,
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void *priv, const void *ns)
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{
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struct kernfs_addrm_cxt acxt;
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struct kernfs_node *kn;
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int rc;
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@ -644,10 +593,7 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
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kn->priv = priv;
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/* link in */
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kernfs_addrm_start(&acxt);
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rc = kernfs_add_one(&acxt, kn);
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kernfs_addrm_finish(&acxt);
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rc = kernfs_add_one(kn);
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if (!rc)
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return kn;
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@ -800,8 +746,7 @@ static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
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return pos->parent;
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}
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static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
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struct kernfs_node *kn)
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static void __kernfs_remove(struct kernfs_node *kn)
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{
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struct kernfs_node *pos;
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@ -845,8 +790,7 @@ static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
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ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
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}
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pos->u.removed_list = acxt->removed;
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acxt->removed = pos;
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kernfs_put(pos);
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}
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kernfs_put(pos);
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*/
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void kernfs_remove(struct kernfs_node *kn)
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{
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struct kernfs_addrm_cxt acxt;
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kernfs_addrm_start(&acxt);
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__kernfs_remove(&acxt, kn);
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kernfs_addrm_finish(&acxt);
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mutex_lock(&kernfs_mutex);
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__kernfs_remove(kn);
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mutex_unlock(&kernfs_mutex);
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}
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/**
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@ -880,7 +822,6 @@ void kernfs_remove(struct kernfs_node *kn)
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int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
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const void *ns)
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{
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struct kernfs_addrm_cxt acxt;
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struct kernfs_node *kn;
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if (!parent) {
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return -ENOENT;
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}
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kernfs_addrm_start(&acxt);
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mutex_lock(&kernfs_mutex);
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kn = kernfs_find_ns(parent, name, ns);
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if (kn)
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__kernfs_remove(&acxt, kn);
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__kernfs_remove(kn);
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kernfs_addrm_finish(&acxt);
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mutex_unlock(&kernfs_mutex);
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if (kn)
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return 0;
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@ -820,7 +820,6 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
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bool name_is_static,
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struct lock_class_key *key)
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{
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struct kernfs_addrm_cxt acxt;
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struct kernfs_node *kn;
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unsigned flags;
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int rc;
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if (ops->mmap)
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kn->flags |= KERNFS_HAS_MMAP;
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kernfs_addrm_start(&acxt);
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rc = kernfs_add_one(&acxt, kn);
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kernfs_addrm_finish(&acxt);
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rc = kernfs_add_one(kn);
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if (rc) {
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kernfs_put(kn);
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return ERR_PTR(rc);
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@ -44,13 +44,6 @@ static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn)
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return kn->dir.root;
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}
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/*
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* Context structure to be used while adding/removing nodes.
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*/
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struct kernfs_addrm_cxt {
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struct kernfs_node *removed;
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};
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/*
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* mount.c
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*/
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struct kernfs_node *kernfs_get_active(struct kernfs_node *kn);
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void kernfs_put_active(struct kernfs_node *kn);
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void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt);
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int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn);
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void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt);
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int kernfs_add_one(struct kernfs_node *kn);
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struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
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const char *name, umode_t mode,
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unsigned flags);
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@ -27,7 +27,6 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
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struct kernfs_node *target)
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{
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struct kernfs_node *kn;
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struct kernfs_addrm_cxt acxt;
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int error;
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kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK);
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kn->symlink.target_kn = target;
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kernfs_get(target); /* ref owned by symlink */
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kernfs_addrm_start(&acxt);
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error = kernfs_add_one(&acxt, kn);
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kernfs_addrm_finish(&acxt);
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error = kernfs_add_one(kn);
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if (!error)
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return kn;
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@ -91,10 +91,6 @@ struct kernfs_node {
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struct rb_node rb;
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union {
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struct kernfs_node *removed_list;
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} u;
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const void *ns; /* namespace tag */
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unsigned int hash; /* ns + name hash */
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union {
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