[PATCH 4.9 08/22] IB/qib: Use struct_size() helper

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Gustavo A. R. Silva <gustavo@embeddedor.com>

commit 829ca44ecf60e9b6f83d0161a6ef10c1304c5060 upstream.

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes, in particular in the
context in which this code is being used.

So, replace the following form:

sizeof(*pkt) + sizeof(pkt->addr[0])*n

with:

struct_size(pkt, addr, n)

Also, notice that variable size is unnecessary, hence it is removed.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/infiniband/hw/qib/qib_user_sdma.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/infiniband/hw/qib/qib_user_sdma.c
+++ b/drivers/infiniband/hw/qib/qib_user_sdma.c
@@ -41,6 +41,7 @@
 #include <linux/rbtree.h>
 #include <linux/spinlock.h>
 #include <linux/delay.h>
+#include <linux/overflow.h>
 
 #include "qib.h"
 #include "qib_user_sdma.h"
@@ -908,10 +909,11 @@ static int qib_user_sdma_queue_pkts(cons
 		}
 
 		if (frag_size) {
-			int pktsize, tidsmsize, n;
+			int tidsmsize, n;
+			size_t pktsize;
 
 			n = npages*((2*PAGE_SIZE/frag_size)+1);
-			pktsize = sizeof(*pkt) + sizeof(pkt->addr[0])*n;
+			pktsize = struct_size(pkt, addr, n);
 
 			/*
 			 * Determine if this is tid-sdma or just sdma.