On Thu, 2017-05-04 at 21:52 +0000, Parav Pandit wrote: > Hi, > > > > > -----Original Message----- > > From: linux-rdma-owner@xxxxxxxxxxxxxxx [mailto:linux-rdma- > > owner@xxxxxxxxxxxxxxx] On Behalf Of Gustavo A. R. Silva > > Sent: Thursday, May 4, 2017 12:42 PM > > To: Doug Ledford <dledford@xxxxxxxxxx>; Sean Hefty > > <sean.hefty@xxxxxxxxx>; Hal Rosenstock <hal.rosenstock@xxxxxxxxx>; > > Sagi > > Grimberg <sagi@xxxxxxxxxx>; Bart Van Assche > > <bart.vanassche@xxxxxxxxxxx>; Steve Wise <swise@opengridcomputing.c > > om>; > > Leon Romanovsky <leonro@xxxxxxxxxxxx>; Yishai Hadas > > <yishaih@xxxxxxxxxxxx>; Moni Shoua <monis@xxxxxxxxxxxx> > > Cc: linux-rdma@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx > > Subject: [infiniband-core] question about arguments position > > > > > > Hello everybody, > > > > While looking into Coverity ID 1351047 I ran into the following > > piece of code at > > drivers/infiniband/core/verbs.c:496: > > > > ret = rdma_addr_find_l2_eth_by_grh(&dgid, &sgid, > > ah_attr->dmac, > > wc->wc_flags & IB_WC_WITH_VLAN > > ? > > NULL : &vlan_id, > > &if_index, &hoplimit); > > > > > > The issue here is that the position of arguments in the call to > > rdma_addr_find_l2_eth_by_grh() function do not match the order of > > the > > parameters: > > > > &dgid is passed to sgid > > &sgid is passed to dgid > > > > This is the function prototype: > > > > int rdma_addr_find_l2_eth_by_grh(const union ib_gid *sgid, > > const union ib_gid *dgid, > > u8 *dmac, u16 *vlan_id, int *if_index, > > int *hoplimit) > > > > My question here is if this is intentional? > > > Yes. ib_init_ah_from_wc() creates ah from the incoming packet. > Incoming packet has dgid of the receiver node on which this code is > getting executed > And sgid contains the GID of the sender. > > When resolving mac address of destination, you use arrived dgid as > sgid. > And use sgid as dgid because sgid contains destinations GID whom to > respond to. A patch to add a comment and forestall future questions here might be a good addition. -- Doug Ledford <dledford@xxxxxxxxxx> GPG KeyID: B826A3330E572FDD Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
