> On 1 May 2018, at 06:38, jackm <jackm@xxxxxxxxxxxxxxxxxx> wrote: > > On Mon, 30 Apr 2018 13:10:49 -0400 > Doug Ledford <dledford@xxxxxxxxxx> wrote: > > Looks good! Yes, absolutely! Håkon > > -Jack > >> On Mon, 2018-04-30 at 08:49 -0600, Jason Gunthorpe wrote: >>> On Mon, Apr 23, 2018 at 10:16:18PM +0300, jackm wrote: >>> >>>>>> TIDs need to be globally unique on the entire machine. >>>> Jason, that is not exactly correct. >>> >>> The expecation for /dev/umad users is that they all receive locally >>> unique TID prefixes. The kernel may be OK to keep things >>> port-specific but it is slightly breaking the API we are presenting >>> to userspace to allow them to alias.. >>> >>> Jason >> >> Would people be happier with this commit message then: >> >> IB/core: Make ib_mad_client_id atomic >> >> Currently, the kernel protects access to the agent ID allocator on a >> per port basis using a spinlock, so it is impossible for two >> apps/threads on the same port to get the same TID, but it is entirely >> possible for two threads on different ports to end up with the same >> TID. >> >> As this can be confusing (regardless of it being legal according to >> the IB Spec 1.3, C13-18.1.1, in section 13.4.6.4 - TransactionID >> usage), and as the rdma-core user space API for /dev/umad devices >> implies unique TIDs even across ports, make the TID an atomic type so >> that no two allocations, regardless of port number, will be the same. >> >> Signed-off-by: Håkon Bugge <haakon.bugge@xxxxxxxxxx> >> Reviewed-by: Jack Morgenstein <jackm@xxxxxxxxxxxxxxxxxx> >> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> >> Reviewed-by: Zhu Yanjun <yanjun.zhu@xxxxxxxxxx> >> Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx> >> >> > > -- > 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 -- 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
