Commit a242c369 authored by Håkon Bugge's avatar Håkon Bugge Committed by Jason Gunthorpe
Browse files

RDMA/netlink: Do not always generate an ACK for some netlink operations 

In rdma_nl_rcv_skb(), the local variable err is assigned the return value
of the supplied callback function, which could be one of
ib_nl_handle_resolve_resp(), ib_nl_handle_set_timeout(), or
ib_nl_handle_ip_res_resp(). These three functions all return skb->len on
success.

rdma_nl_rcv_skb() is merely a copy of netlink_rcv_skb(). The callback
functions used by the latter have the convention: "Returns 0 on success or
a negative error code".

In particular, the statement (equal for both functions):

   if (nlh->nlmsg_flags & NLM_F_ACK || err)

implies that rdma_nl_rcv_skb() always will ack a message, independent of
the NLM_F_ACK being set in nlmsg_flags or not.

The fix could be to change the above statement, but it is better to keep
the two *_rcv_skb() functions equal in this respect and instead change the
three callback functions in the rdma subsystem to the correct convention.

Fixes: 2ca546b9 ("IB/sa: Route SA pathrecord query through netlink")
Fixes: ae43f828 ("IB/core: Add IP to GID netlink offload")
Link: https://lore.kernel.org/r/20191216120436.3204814-1-haakon.bugge@oracle.com


Suggested-by: default avatarMark Haywood <mark.haywood@oracle.com>
Signed-off-by: default avatarHåkon Bugge <haakon.bugge@oracle.com>
Tested-by: default avatarMark Haywood <mark.haywood@oracle.com>
Reviewed-by: default avatarLeon Romanovsky <leonro@mellanox.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: default avatarJason Gunthorpe <jgg@mellanox.com>
parent b5671afe

drivers/infiniband/core/addr.c

+1 −1
Original line number Diff line number Diff line
@@ -139,7 +139,7 @@ int ib_nl_handle_ip_res_resp(struct sk_buff *skb, 
	if (ib_nl_is_good_ip_resp(nlh))

		ib_nl_process_good_ip_rsep(nlh);



	return skb->len;

	return 0;

}



static int ib_nl_ip_send_msg(struct rdma_dev_addr *dev_addr,

drivers/infiniband/core/sa_query.c

+2 −2
Original line number Diff line number Diff line
@@ -1068,7 +1068,7 @@ int ib_nl_handle_set_timeout(struct sk_buff *skb, 
	}



settimeout_out:

	return skb->len;

	return 0;

}



static inline int ib_nl_is_good_resolve_resp(const struct nlmsghdr *nlh)
@@ -1139,7 +1139,7 @@ int ib_nl_handle_resolve_resp(struct sk_buff *skb, 
	}



resp_out:

	return skb->len;

	return 0;

}



static void free_sm_ah(struct kref *kref)