[PATCH] add __fput for aio

This patch splits fput into fput and __fput.  __fput is needed by aio to
construct a mechanism for performing a deferred fput during io
completion, which typically occurs during interrupt context.

fs/file_table.c

@@ -99,12 +99,20 @@ int init_private_file(struct file *filp, struct dentry *dentry, int mode)
 }
 
 void fput(struct file * file)
+{
+	if (atomic_dec_and_test(&file->f_count))
+		__fput(file);
+}
+
+/* __fput is called from task context when aio completion releases the last
+ * last use of a struct file *.  Do not use otherwise.
+ */
+void __fput(struct file * file)
 {
 	struct dentry * dentry = file->f_dentry;
 	struct vfsmount * mnt = file->f_vfsmnt;
 	struct inode * inode = dentry->d_inode;
 
-	if (atomic_dec_and_test(&file->f_count)) {
 	locks_remove_flock(file);
 
 	if (file->f_iobuf)
@@ -124,7 +132,6 @@ void fput(struct file * file)
 	file_list_unlock();
 	dput(dentry);
 	mntput(mnt);
-	}
 }
 
 struct file * fget(unsigned int fd)

include/linux/file.h

@@ -33,6 +33,7 @@ struct files_struct {
         struct file * fd_array[NR_OPEN_DEFAULT];
 };
 
+extern void FASTCALL(__fput(struct file *));
 extern void FASTCALL(fput(struct file *));
 extern struct file * FASTCALL(fget(unsigned int fd));
 extern void FASTCALL(set_close_on_exec(unsigned int fd, int flag));