diff options
Diffstat (limited to 'fs/file_table.c')
-rw-r--r-- | fs/file_table.c | 40 |
1 files changed, 23 insertions, 17 deletions
diff --git a/fs/file_table.c b/fs/file_table.c index e68e97d4f00a..a79a80031343 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -65,33 +65,33 @@ static void file_free_rcu(struct rcu_head *head) { struct file *f = container_of(head, struct file, f_rcuhead); - put_cred(f->f_cred); - if (unlikely(f->f_mode & FMODE_BACKING)) - kfree(backing_file(f)); - else - kmem_cache_free(filp_cachep, f); + kfree(backing_file(f)); } static inline void file_free(struct file *f) { security_file_free(f); - if (unlikely(f->f_mode & FMODE_BACKING)) - path_put(backing_file_real_path(f)); if (likely(!(f->f_mode & FMODE_NOACCOUNT))) percpu_counter_dec(&nr_files); - call_rcu(&f->f_rcuhead, file_free_rcu); + put_cred(f->f_cred); + if (unlikely(f->f_mode & FMODE_BACKING)) { + path_put(backing_file_real_path(f)); + call_rcu(&f->f_rcuhead, file_free_rcu); + } else { + kmem_cache_free(filp_cachep, f); + } } void release_empty_file(struct file *f) { WARN_ON_ONCE(f->f_mode & (FMODE_BACKING | FMODE_OPENED)); - /* Uhm, we better find out who grabs references to an unopened file. */ - WARN_ON_ONCE(atomic_long_cmpxchg(&f->f_count, 1, 0) != 1); - security_file_free(f); - put_cred(f->f_cred); - if (likely(!(f->f_mode & FMODE_NOACCOUNT))) - percpu_counter_dec(&nr_files); - kmem_cache_free(filp_cachep, f); + if (atomic_long_dec_and_test(&f->f_count)) { + security_file_free(f); + put_cred(f->f_cred); + if (likely(!(f->f_mode & FMODE_NOACCOUNT))) + percpu_counter_dec(&nr_files); + kmem_cache_free(filp_cachep, f); + } } /* @@ -176,7 +176,6 @@ static int init_file(struct file *f, int flags, const struct cred *cred) return error; } - atomic_long_set(&f->f_count, 1); rwlock_init(&f->f_owner.lock); spin_lock_init(&f->f_lock); mutex_init(&f->f_pos_lock); @@ -184,6 +183,12 @@ static int init_file(struct file *f, int flags, const struct cred *cred) f->f_mode = OPEN_FMODE(flags); /* f->f_version: 0 */ + /* + * We're SLAB_TYPESAFE_BY_RCU so initialize f_count last. While + * fget-rcu pattern users need to be able to handle spurious + * refcount bumps we should reinitialize the reused file first. + */ + atomic_long_set(&f->f_count, 1); return 0; } @@ -483,7 +488,8 @@ EXPORT_SYMBOL(__fput_sync); void __init files_init(void) { filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0, - SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT, NULL); + SLAB_TYPESAFE_BY_RCU | SLAB_HWCACHE_ALIGN | + SLAB_PANIC | SLAB_ACCOUNT, NULL); percpu_counter_init(&nr_files, 0, GFP_KERNEL); } |