linux-kernel - [PATCH v2 1/2] staging: r8188eu: simplify complex pointer casting

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Message-ID: <1428580d09a9916899209c9278dca40ee2d297d3.1667755987.git.drv@mailo.com>
Date:   Sun, 6 Nov 2022 23:25:37 +0530
From:   Deepak R Varma <drv@...lo.com>
To:     Larry Finger <Larry.Finger@...inger.net>,
        Phillip Potter <phil@...lpotter.co.uk>,
        Pavel Skripkin <paskripkin@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: [PATCH v2 1/2] staging: r8188eu: simplify complex pointer casting

Pointers to structures udphdr and dhcpMessage are derived by casting
adjacent pointers with size_t. Such typecast of pointer using size_t
is not preferred. The code looks complex and delicate. Simplify such
casting by utilizing generic "void *" casting.

Suggested-by: Joe Perches <joe@...ches.com>
Signed-off-by: Deepak R Varma <drv@...lo.com>
---

Changes in v2:
   1. Separate the change associated with variable cookie in a separate patch.
      Now in patch 2 of this set. Suggested by gregkh@...uxfoundation.org
   2. Correct variable ordering. Code cimplified to match current style.
      Feedback from gregkh@...uxfoundation.org.



 drivers/staging/r8188eu/core/rtw_br_ext.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_br_ext.c b/drivers/staging/r8188eu/core/rtw_br_ext.c
index a23f7df373ed..4deaa7e352a3 100644
--- a/drivers/staging/r8188eu/core/rtw_br_ext.c
+++ b/drivers/staging/r8188eu/core/rtw_br_ext.c
@@ -610,12 +610,11 @@ void dhcp_flag_bcast(struct adapter *priv, struct sk_buff *skb)
 			struct iphdr *iph = (struct iphdr *)(skb->data + ETH_HLEN);

 			if (iph->protocol == IPPROTO_UDP) { /*  UDP */
-				struct udphdr *udph = (struct udphdr *)((size_t)iph + (iph->ihl << 2));
+				struct udphdr *udph = (void *)iph + (iph->ihl << 2);

 				if ((udph->source == htons(CLIENT_PORT)) &&
 				    (udph->dest == htons(SERVER_PORT))) { /*  DHCP request */
-					struct dhcpMessage *dhcph =
-						(struct dhcpMessage *)((size_t)udph + sizeof(struct udphdr));
+					struct dhcpMessage *dhcph = (void *)udph + sizeof(struct udphdr);
 					u32 cookie = be32_to_cpu((__be32)dhcph->cookie);

 					if (cookie == DHCP_MAGIC) { /*  match magic word */
--
2.34.1