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netlink: Make groups check less stupid in netlink_bind() 

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Dmitry Safonov 2018-09-03 22:40:51 +01:00 committed by David S. Miller
parent fa788d986a
commit 428f944bd5
1 changed files with 2 additions and 4 deletions
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6
net/netlink/af_netlink.c
View File

@ -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;