diff options
| -rw-r--r-- | fs/kernfs/file.c | 56 |
1 files changed, 38 insertions, 18 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 7d9138d2be3b..3b354caad6b5 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -49,6 +49,22 @@ struct kernfs_open_node { static LLIST_HEAD(kernfs_notify_list); +static inline struct mutex *kernfs_open_file_mutex_ptr(struct kernfs_node *kn) +{ + return &kernfs_open_file_mutex; +} + +static inline struct mutex *kernfs_open_file_mutex_lock(struct kernfs_node *kn) +{ + struct mutex *lock; + + lock = kernfs_open_file_mutex_ptr(kn); + + mutex_lock(lock); + + return lock; +} + /** * kernfs_deref_open_node - Get kernfs_open_node corresponding to @kn. * @@ -79,9 +95,9 @@ kernfs_deref_open_node(struct kernfs_open_file *of, struct kernfs_node *kn) * @kn: target kernfs_node. * * Fetch and return ->attr.open of @kn when caller holds the - * kernfs_open_file_mutex. + * kernfs_open_file_mutex_ptr(kn). * - * Update of ->attr.open happens under kernfs_open_file_mutex. So when + * Update of ->attr.open happens under kernfs_open_file_mutex_ptr(kn). So when * the caller guarantees that this mutex is being held, other updaters can't * change ->attr.open and this means that we can safely deref ->attr.open * outside RCU read-side critical section. @@ -92,7 +108,7 @@ static struct kernfs_open_node * kernfs_deref_open_node_protected(struct kernfs_node *kn) { return rcu_dereference_protected(kn->attr.open, - lockdep_is_held(&kernfs_open_file_mutex)); + lockdep_is_held(kernfs_open_file_mutex_ptr(kn))); } static struct kernfs_open_file *kernfs_of(struct file *file) @@ -574,19 +590,20 @@ static int kernfs_get_open_node(struct kernfs_node *kn, struct kernfs_open_file *of) { struct kernfs_open_node *on, *new_on = NULL; + struct mutex *mutex = NULL; - mutex_lock(&kernfs_open_file_mutex); + mutex = kernfs_open_file_mutex_lock(kn); on = kernfs_deref_open_node_protected(kn); if (on) { list_add_tail(&of->list, &on->files); - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); return 0; } else { /* not there, initialize a new one */ new_on = kmalloc(sizeof(*new_on), GFP_KERNEL); if (!new_on) { - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); return -ENOMEM; } atomic_set(&new_on->event, 1); @@ -595,7 +612,7 @@ static int kernfs_get_open_node(struct kernfs_node *kn, list_add_tail(&of->list, &new_on->files); rcu_assign_pointer(kn->attr.open, new_on); } - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); return 0; } @@ -617,12 +634,13 @@ static void kernfs_unlink_open_file(struct kernfs_node *kn, struct kernfs_open_file *of) { struct kernfs_open_node *on; + struct mutex *mutex = NULL; - mutex_lock(&kernfs_open_file_mutex); + mutex = kernfs_open_file_mutex_lock(kn); on = kernfs_deref_open_node_protected(kn); if (!on) { - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); return; } @@ -634,7 +652,7 @@ static void kernfs_unlink_open_file(struct kernfs_node *kn, kfree_rcu(on, rcu_head); } - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); } static int kernfs_fop_open(struct inode *inode, struct file *file) @@ -772,11 +790,11 @@ static void kernfs_release_file(struct kernfs_node *kn, /* * @of is guaranteed to have no other file operations in flight and * we just want to synchronize release and drain paths. - * @kernfs_open_file_mutex is enough. @of->mutex can't be used + * @kernfs_open_file_mutex_ptr(kn) is enough. @of->mutex can't be used * here because drain path may be called from places which can * cause circular dependency. */ - lockdep_assert_held(&kernfs_open_file_mutex); + lockdep_assert_held(kernfs_open_file_mutex_ptr(kn)); if (!of->released) { /* @@ -793,11 +811,12 @@ static int kernfs_fop_release(struct inode *inode, struct file *filp) { struct kernfs_node *kn = inode->i_private; struct kernfs_open_file *of = kernfs_of(filp); + struct mutex *mutex = NULL; if (kn->flags & KERNFS_HAS_RELEASE) { - mutex_lock(&kernfs_open_file_mutex); + mutex = kernfs_open_file_mutex_lock(kn); kernfs_release_file(kn, of); - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); } kernfs_unlink_open_file(kn, of); @@ -812,6 +831,7 @@ void kernfs_drain_open_files(struct kernfs_node *kn) { struct kernfs_open_node *on; struct kernfs_open_file *of; + struct mutex *mutex = NULL; if (!(kn->flags & (KERNFS_HAS_MMAP | KERNFS_HAS_RELEASE))) return; @@ -821,16 +841,16 @@ void kernfs_drain_open_files(struct kernfs_node *kn) * ->attr.open at this point of time. This check allows early bail out * if ->attr.open is already NULL. kernfs_unlink_open_file makes * ->attr.open NULL only while holding kernfs_open_file_mutex so below - * check under kernfs_open_file_mutex will ensure bailing out if + * check under kernfs_open_file_mutex_ptr(kn) will ensure bailing out if * ->attr.open became NULL while waiting for the mutex. */ if (!rcu_access_pointer(kn->attr.open)) return; - mutex_lock(&kernfs_open_file_mutex); + mutex = kernfs_open_file_mutex_lock(kn); on = kernfs_deref_open_node_protected(kn); if (!on) { - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); return; } @@ -844,7 +864,7 @@ void kernfs_drain_open_files(struct kernfs_node *kn) kernfs_release_file(kn, of); } - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); } /* |