lkml.org 
[lkml]   [2018]   [Sep]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] netlink: Make groups check less stupid in netlink_bind()
Date
As Linus noted, the test for 0 is needless, groups type can follow the
usual kernel style and 8*sizeof(unsigned long) is BITS_PER_LONG:

> The code [..] isn't technically incorrect...
> But it is stupid.
> Why stupid? Because the test for 0 is pointless.
>
> Just doing
> if (nlk->ngroups < 8*sizeof(groups))
> groups &= (1UL << nlk->ngroups) - 1;
>
> would have been fine and more understandable, since the "mask by shift
> count" already does the right thing for a ngroups value of 0. Now that
> test for zero makes me go "what's special about zero?". It turns out
> that the answer to that is "nothing".
[..]
> The type of "groups" is kind of silly too.
>
> Yeah, "long unsigned int" isn't _technically_ wrong. But we normally
> call that type "unsigned long".

Cleanup my piece of pointlessness.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: netdev@vger.kernel.org
Fairly-blamed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
net/netlink/af_netlink.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 930d17fa906c..b4a29bcc33b9 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -993,7 +993,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
struct netlink_sock *nlk = nlk_sk(sk);
struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;
int err = 0;
- long unsigned int groups = nladdr->nl_groups;
+ unsigned long groups = nladdr->nl_groups;
bool bound;

if (addr_len < sizeof(struct sockaddr_nl))
@@ -1011,9 +1011,7 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
return err;
}

- if (nlk->ngroups == 0)
- groups = 0;
- else if (nlk->ngroups < 8*sizeof(groups))
+ if (nlk->ngroups < BITS_PER_LONG)
groups &= (1UL << nlk->ngroups) - 1;

bound = nlk->bound;
--
2.13.6
\
 
 \ /
  Last update: 2018-09-03 23:41    [W:0.060 / U:9.524 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site