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For example next patch modifies this interface to use hashed mutexes in place of a single global kernfs_open_file_mutex. Signed-off-by: Imran Khan --- fs/kernfs/file.c | 50 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 35 insertions(+), 15 deletions(-) diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 96c8493003b6..7a60074ec0a0 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; +} + /* * Raw deref RCU protected kn->attr.open. * The caller guarantees that @on will not vanish in the middle of this @@ -67,7 +83,7 @@ static struct kernfs_open_node *kernfs_deref_on_raw(struct kernfs_node *kn) static struct kernfs_open_node *kernfs_deref_on_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))); } /* @@ -78,7 +94,7 @@ static struct kernfs_open_node *kernfs_deref_on_protected(struct kernfs_node *kn static struct kernfs_open_node *kernfs_check_on_protected(struct kernfs_node *kn) { return rcu_dereference_check(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) @@ -551,19 +567,20 @@ 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_on_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); @@ -572,7 +589,7 @@ 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; } @@ -594,12 +611,13 @@ 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_on_protected(kn); if (!on) { - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); return; } @@ -611,7 +629,7 @@ 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) @@ -753,7 +771,7 @@ static void kernfs_release_file(struct kernfs_node *kn, * 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) { /* @@ -770,11 +788,12 @@ 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); @@ -789,6 +808,7 @@ 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; @@ -804,10 +824,10 @@ void kernfs_drain_open_files(struct kernfs_node *kn) if (!rcu_access_pointer(kn->attr.open)) return; - mutex_lock(&kernfs_open_file_mutex); + mutex = kernfs_open_file_mutex_lock(kn); on = kernfs_check_on_protected(kn); if (!on) { - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); return; } @@ -821,7 +841,7 @@ void kernfs_drain_open_files(struct kernfs_node *kn) kernfs_release_file(kn, of); } - mutex_unlock(&kernfs_open_file_mutex); + mutex_unlock(mutex); } /* -- 2.30.2