[01/16] SUNRPC: _shift_data_left/right_pages should check the shift length

Commit Message

Trond Myklebust Dec. 9, 2020, 2:47 p.m. UTC

From: Trond Myklebust <[e-mail]>

Exit early if the shift is zero.

Signed-off-by: Trond Myklebust <[e-mail]>
---
 net/sunrpc/xdr.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

Patch

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index f9efc207a7d5..1d48934bdf9e 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -226,6 +226,9 @@  _shift_data_left_pages(struct page **pages, size_t pgto_base,
 
 	BUG_ON(pgfrom_base <= pgto_base);
 
+	if (!len)
+		return;
+
 	pgto = pages + (pgto_base >> PAGE_SHIFT);
 	pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
 
@@ -308,6 +311,9 @@  _shift_data_right_pages(struct page **pages, size_t pgto_base,
 
 	BUG_ON(pgto_base <= pgfrom_base);
 
+	if (!len)
+		return;
+
 	pgto_base += len;
 	pgfrom_base += len;
 
@@ -406,6 +412,9 @@  _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
 	char *vto;
 	size_t copy;
 
+	if (!len)
+		return;
+
 	pgto = pages + (pgbase >> PAGE_SHIFT);
 	pgbase &= ~PAGE_MASK;
 
@@ -450,6 +459,9 @@  _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
 	char *vfrom;
 	size_t copy;
 
+	if (!len)
+		return;
+
 	pgfrom = pages + (pgbase >> PAGE_SHIFT);
 	pgbase &= ~PAGE_MASK;