linux-kernel - [PATCH bpf-next] xsk: fix 64-bit division

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Message-Id: <20180507174350.3534-1-bjorn.topel@gmail.com>
Date:   Mon,  7 May 2018 19:43:50 +0200
From:   Björn Töpel <bjorn.topel@...il.com>
To:     ast@...com, daniel@...earbox.net, netdev@...r.kernel.org
Cc:     Björn Töpel <bjorn.topel@...el.com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        magnus.karlsson@...el.com, linux-next@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH bpf-next] xsk: fix 64-bit division

From: Björn Töpel <bjorn.topel@...el.com>

i386 builds report:
  net/xdp/xdp_umem.o: In function `xdp_umem_reg':
  xdp_umem.c:(.text+0x47e): undefined reference to `__udivdi3'

This fix uses div_u64 instead of the GCC built-in.

Fixes: c0c77d8fb787 ("xsk: add user memory registration support sockopt")
Signed-off-by: Björn Töpel <bjorn.topel@...el.com>
---
 net/xdp/xdp_umem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/xdp/xdp_umem.c b/net/xdp/xdp_umem.c
index 881dfdefe235..2b47a1dd7c6c 100644
--- a/net/xdp/xdp_umem.c
+++ b/net/xdp/xdp_umem.c
@@ -209,7 +209,7 @@ int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	if ((addr + size) < addr)
 		return -EINVAL;
 
-	nframes = size / frame_size;
+	nframes = (unsigned int)div_u64(size, frame_size);
 	if (nframes == 0 || nframes > UINT_MAX)
 		return -EINVAL;
 
-- 
2.14.1