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-rw-r--r--fs/file.c100
1 files changed, 99 insertions, 1 deletions
diff --git a/fs/file.c b/fs/file.c
index a3a0705f8f51..0be423cadb26 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -84,7 +84,7 @@ static void free_fdtable_work(struct work_struct *work)
}
}
-void free_fdtable_rcu(struct rcu_head *rcu)
+static void free_fdtable_rcu(struct rcu_head *rcu)
{
struct fdtable *fdt = container_of(rcu, struct fdtable, rcu);
struct fdtable_defer *fddef;
@@ -116,6 +116,11 @@ void free_fdtable_rcu(struct rcu_head *rcu)
}
}
+static inline void free_fdtable(struct fdtable *fdt)
+{
+ call_rcu(&fdt->rcu, free_fdtable_rcu);
+}
+
/*
* Expand the fdset in the files_struct. Called with the files spinlock
* held for write.
@@ -388,6 +393,99 @@ out:
return NULL;
}
+static void close_files(struct files_struct * files)
+{
+ int i, j;
+ struct fdtable *fdt;
+
+ j = 0;
+
+ /*
+ * It is safe to dereference the fd table without RCU or
+ * ->file_lock because this is the last reference to the
+ * files structure. But use RCU to shut RCU-lockdep up.
+ */
+ rcu_read_lock();
+ fdt = files_fdtable(files);
+ rcu_read_unlock();
+ for (;;) {
+ unsigned long set;
+ i = j * BITS_PER_LONG;
+ if (i >= fdt->max_fds)
+ break;
+ set = fdt->open_fds[j++];
+ while (set) {
+ if (set & 1) {
+ struct file * file = xchg(&fdt->fd[i], NULL);
+ if (file) {
+ filp_close(file, files);
+ cond_resched();
+ }
+ }
+ i++;
+ set >>= 1;
+ }
+ }
+}
+
+struct files_struct *get_files_struct(struct task_struct *task)
+{
+ struct files_struct *files;
+
+ task_lock(task);
+ files = task->files;
+ if (files)
+ atomic_inc(&files->count);
+ task_unlock(task);
+
+ return files;
+}
+
+void put_files_struct(struct files_struct *files)
+{
+ struct fdtable *fdt;
+
+ if (atomic_dec_and_test(&files->count)) {
+ close_files(files);
+ /*
+ * Free the fd and fdset arrays if we expanded them.
+ * If the fdtable was embedded, pass files for freeing
+ * at the end of the RCU grace period. Otherwise,
+ * you can free files immediately.
+ */
+ rcu_read_lock();
+ fdt = files_fdtable(files);
+ if (fdt != &files->fdtab)
+ kmem_cache_free(files_cachep, files);
+ free_fdtable(fdt);
+ rcu_read_unlock();
+ }
+}
+
+void reset_files_struct(struct files_struct *files)
+{
+ struct task_struct *tsk = current;
+ struct files_struct *old;
+
+ old = tsk->files;
+ task_lock(tsk);
+ tsk->files = files;
+ task_unlock(tsk);
+ put_files_struct(old);
+}
+
+void exit_files(struct task_struct *tsk)
+{
+ struct files_struct * files = tsk->files;
+
+ if (files) {
+ task_lock(tsk);
+ tsk->files = NULL;
+ task_unlock(tsk);
+ put_files_struct(files);
+ }
+}
+
static void __devinit fdtable_defer_list_init(int cpu)
{
struct fdtable_defer *fddef = &per_cpu(fdtable_defer_list, cpu);