netdev - [PATCH v2 11/13] netpoll: avoid put_unaligned() on single character

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Date:   Fri, 14 May 2021 12:00:59 +0200
From:   Arnd Bergmann <arnd@...nel.org>
To:     linux-arch@...r.kernel.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Vineet Gupta <vgupta@...opsys.com>,
        Arnd Bergmann <arnd@...db.de>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Florian Fainelli <f.fainelli@...il.com>,
        Andrew Lunn <andrew@...n.ch>,
        Vladimir Oltean <vladimir.oltean@....com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2 11/13] netpoll: avoid put_unaligned() on single character

From: Arnd Bergmann <arnd@...db.de>

With a planned cleanup, using put_unaligned() on a single character
results in a harmless warning:

In file included from ./arch/x86/include/generated/asm/unaligned.h:1,
                 from include/linux/etherdevice.h:24,
                 from net/core/netpoll.c:18:
net/core/netpoll.c: In function 'netpoll_send_udp':
include/asm-generic/unaligned.h:23:9: error: 'packed' attribute ignored for field of type 'unsigned char' [-Werror=attributes]
net/core/netpoll.c:431:3: note: in expansion of macro 'put_unaligned'
  431 |   put_unaligned(0x60, (unsigned char *)ip6h);
      |   ^~~~~~~~~~~~~
include/asm-generic/unaligned.h:23:9: error: 'packed' attribute ignored for field of type 'unsigned char' [-Werror=attributes]
net/core/netpoll.c:459:3: note: in expansion of macro 'put_unaligned'
  459 |   put_unaligned(0x45, (unsigned char *)iph);
      |   ^~~~~~~~~~~~~

Replace this with an open-coded pointer dereference.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 net/core/netpoll.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index c310c7c1cef7..9c49a38fa315 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -428,7 +428,7 @@ void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 		ip6h = ipv6_hdr(skb);
 
 		/* ip6h->version = 6; ip6h->priority = 0; */
-		put_unaligned(0x60, (unsigned char *)ip6h);
+		*(unsigned char *)ip6h = 0x60;
 		ip6h->flow_lbl[0] = 0;
 		ip6h->flow_lbl[1] = 0;
 		ip6h->flow_lbl[2] = 0;
@@ -456,7 +456,7 @@ void netpoll_send_udp(struct netpoll *np, const char *msg, int len)
 		iph = ip_hdr(skb);
 
 		/* iph->version = 4; iph->ihl = 5; */
-		put_unaligned(0x45, (unsigned char *)iph);
+		*(unsigned char *)iph = 0x45;
 		iph->tos      = 0;
 		put_unaligned(htons(ip_len), &(iph->tot_len));
 		iph->id       = htons(atomic_inc_return(&ip_ident));
-- 
2.29.2