From: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
We need to do this step during READ_PLUS decoding so that we know pages
are the right length and any extra data has been preserved in the tail.
Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx>
---
include/linux/sunrpc/xdr.h | 1 +
net/sunrpc/xdr.c | 30 ++++++++++++++++++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index b375b284afbe..607340fa1fd4 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -262,6 +262,7 @@ extern __be32 *xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes);
extern unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len);
extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len);
extern int xdr_process_buf(const struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);
+extern void xdr_set_pagelen(struct xdr_stream *, unsigned int len);
extern unsigned int xdr_align_data(struct xdr_stream *, unsigned int offset, unsigned int length);
extern unsigned int xdr_expand_hole(struct xdr_stream *, unsigned int offset, unsigned int length);
extern bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index d71c90552fa2..ff36a20aab89 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -1509,6 +1509,36 @@ unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
}
EXPORT_SYMBOL_GPL(xdr_read_pages);
+/**
+ * xdr_set_pagelen - Sets the length of the XDR pages
+ * @xdr: pointer to xdr_stream struct
+ * @len: new length of the XDR page data
+ *
+ * Either grows or shrinks the length of the xdr pages by setting pagelen to
+ * @len bytes. When shrinking, any extra data is moved into buf->tail, whereas
+ * when growing any data beyond the current pointer is moved into the tail.
+ *
+ * Returns True if the operation was successful, and False otherwise.
+ */
+void xdr_set_pagelen(struct xdr_stream *xdr, unsigned int len)
+{
+ struct xdr_buf *buf = xdr->buf;
+ size_t remaining = xdr_stream_remaining(xdr);
+ size_t base = 0;
+
+ if (len < buf->page_len) {
+ base = buf->page_len - len;
+ xdr_shrink_pagelen(buf, len);
+ } else {
+ xdr_buf_head_shift_right(buf, xdr_stream_pos(xdr),
+ buf->page_len, remaining);
+ if (len > buf->page_len)
+ xdr_buf_try_expand(buf, len - buf->page_len);
+ }
+ xdr_set_tail_base(xdr, base, remaining);
+}
+EXPORT_SYMBOL_GPL(xdr_set_pagelen);
+
unsigned int xdr_align_data(struct xdr_stream *xdr, unsigned int offset,
unsigned int length)
{
--
2.36.1
