[PATCH V2] net: qrtr: use protocol endiannes variable

From: Nicholas Mc Guire
Date: Fri May 10 2019 - 21:04:16 EST

sparse was unable to verify endiannes correctness due to reassignment
from le32_to_cpu to the same variable - fix this warning up by providing
a proper __le32 type and initializing it. This is not actually fixing
any bug - rather just addressing the sparse warning.

Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx>

Problem located by an experimental coccinelle script to locate
patters that make sparse unhappy (false positives):

V2: Reorder variables to preserve reverse christmas tree ordering
as requested by David Miller <davem@xxxxxxxxxxxxx>.

sparse was unhappy about:
net/qrtr/qrtr.c:811:24: warning: cast to restricted __le32

The patch does change the binary - from inspection of the .lst files
it seems that the additional variable as well instruction reordering
constraints change the code even if the code-logic is the same.

Patch was compile-tested with: qcom_defconfig + QRTR=m
(with some unrelated warnings about not implemented system calls)

Patch is against 5.1 (localversion-next is next-20190510)

net/qrtr/qrtr.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index dd0e97f..801872a 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -728,12 +728,13 @@ static int qrtr_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
DECLARE_SOCKADDR(struct sockaddr_qrtr *, addr, msg->msg_name);
int (*enqueue_fn)(struct qrtr_node *, struct sk_buff *, int,
struct sockaddr_qrtr *, struct sockaddr_qrtr *);
+ __le32 qrtr_type = cpu_to_le32(QRTR_TYPE_DATA);
struct qrtr_sock *ipc = qrtr_sk(sock->sk);
struct sock *sk = sock->sk;
struct qrtr_node *node;
struct sk_buff *skb;
+ u32 type = 0;
size_t plen;
- u32 type = QRTR_TYPE_DATA;
int rc;

if (msg->msg_flags & ~(MSG_DONTWAIT))
@@ -807,8 +808,8 @@ static int qrtr_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)

/* control messages already require the type as 'command' */
- skb_copy_bits(skb, 0, &type, 4);
- type = le32_to_cpu(type);
+ skb_copy_bits(skb, 0, &qrtr_type, 4);
+ type = le32_to_cpu(qrtr_type);

rc = enqueue_fn(node, skb, type, &ipc->us, addr);