1 files changed, 19 insertions, 0 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index b7f4a1f94d48..9c0485236e68 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -97,6 +97,23 @@ loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
 }
 EXPORT_SYMBOL(generic_file_llseek);
 
+/**
+ * noop_llseek - No Operation Performed llseek implementation
+ * @file:       file structure to seek on
+ * @offset:     file offset to seek to
+ * @origin:     type of seek
+ *
+ * This is an implementation of ->llseek useable for the rare special case when
+ * userspace expects the seek to succeed but the (device) file is actually not
+ * able to perform the seek. In this case you use noop_llseek() instead of
+ * falling back to the default implementation of ->llseek.
+ */
+loff_t noop_llseek(struct file *file, loff_t offset, int origin)
+{
+        return file->f_pos;
+}
+EXPORT_SYMBOL(noop_llseek);
+
 loff_t no_llseek(struct file *file, loff_t offset, int origin)
 {
         return -ESPIPE;
@@ -258,6 +275,7 @@ ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *pp
         init_sync_kiocb(&kiocb, filp);
         kiocb.ki_pos = *ppos;
         kiocb.ki_left = len;
+        kiocb.ki_nbytes = len;
 
         for (;;) {
                 ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
@@ -313,6 +331,7 @@ ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, lof
         init_sync_kiocb(&kiocb, filp);
         kiocb.ki_pos = *ppos;
         kiocb.ki_left = len;
+        kiocb.ki_nbytes = len;
 
         for (;;) {
                 ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);