Signed-off-by: Jeff Layton <jeff.layton@xxxxxxxxxxxxxxx>
---
fs/file_table.c | 18 ++++++++++++++++++
include/linux/file.h | 1 +
2 files changed, 19 insertions(+)
diff --git a/fs/file_table.c b/fs/file_table.c
index d63f4a399d39..1ad2e3fd2064 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -297,6 +297,24 @@ void fput(struct file *file)
}
EXPORT_SYMBOL(fput);
+/**
+ * fput_queue - do an fput without using task_work
+ * @file: file of which to put the reference
+ *
+ * If we need to ensure that the final __fput is done on a file before
+ * returning to userland, then we can't queue it to task_work. For that we
+ * borrow the infrastructure used by kthreads, and the task can then just
+ * called flush_delayed_fput to ensure that the final fput has completed.
+ */
+void fput_queue(struct file *file)
+{
+ if (atomic_long_dec_and_test(&file->f_count)) {
+ if (llist_add(&file->f_u.fu_llist, &delayed_fput_list))
+ schedule_delayed_work(&delayed_fput_work, 1);
+ }
+}
+EXPORT_SYMBOL(fput_queue);
+
/*
* synchronous analog of fput(); for kernel threads that might be needed
* in some umount() (and thus can't use flush_delayed_fput() without
diff --git a/include/linux/file.h b/include/linux/file.h
index f87d30882a24..543b0e2faf2c 100644
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -12,6 +12,7 @@
struct file;
extern void fput(struct file *);
+extern void fput_queue(struct file *);
struct file_operations;
struct vfsmount;
--
2.4.3
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