From: Trond Myklebust <trond.myklebust@hammerspace.com>
Date: Mon, 7 Dec 2020 18:30:46 +0000 (-0500)
Subject: SUNRPC: _shift_data_left/right_pages should check the shift length
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c54e959b36cbdb0cb2f2805e3e945dd83476a5c7;p=linux.git

SUNRPC: _shift_data_left/right_pages should check the shift length

Exit early if the shift is zero.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index c852d199c789e..5833329c132c8 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -225,6 +225,9 @@ _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);
 
@@ -307,6 +310,9 @@ _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;
 
@@ -405,6 +411,9 @@ _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;
 
@@ -449,6 +458,9 @@ _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;