Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH] IB/core: Make ib_mad_client_id atomic | From | Håkon Bugge <> | Date | Mon, 30 Apr 2018 13:50:57 +0200 |
| |
> On 27 Apr 2018, at 21:08, Doug Ledford <dledford@redhat.com> wrote: > > On Thu, 2018-04-26 at 20:51 +0200, Håkon Bugge wrote: >>> Jason is out this week. I'll end up processing this one (probably later >>> today). But I’ll fix up the commit message to suit my tastes when I do. >> >> Thank you, Doug and Jack, > > I reworded the commit message, let me know if you think I worded it > wrong: > > commit 69f01b81539c62f3dd96f9f02138ad7b839a0c70 (HEAD -> k.o/wip/dl-for-rc) > Author: Håkon Bugge <haakon.bugge@oracle.com> > Date: Wed Apr 18 16:24:50 2018 +0200 > > IB/core: Make ib_mad_client_id atomic > > Currently, 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: "Then initiating > a new operation, MADHeader:TransactionID shall be set to such a value > that within that MAD the combination of TIG, SGID, and MgmtClass is > different from that of any other currently executing operation. If the > MAD does not have a GRH, its SLID is used in the combination in place of > an SGID." which guarantees we are legal because our different ports will > have different SGID/SLID creating a unique tuple even if the TIDs are > identical), and as we might want to open the TID allocator up to more > parallel usage later, make the TID an atomic type so that no two > allocations, regardless of port number, will be the same.
The wording is OK per se, but the last sentence spans 12 lines - and as such - a little bit hard to comprehend. I suggest just to refer to IB Spec 1.3, clause C13-18.1.1 and not quote it and make the last sub-sentence (starting with “and as we might want to open”) a sentence by its own.
Thxs, Håkon
> > Signed-off-by: Håkon Bugge <haakon.bugge@oracle.com> > Reviewed-by: Jack Morgenstein <jackm@dev.mellanox.co.il> > Reviewed-by: Ira Weiny <ira.weiny@intel.com> > Reviewed-by: Zhu Yanjun <yanjun.zhu@oracle.com> > Signed-off-by: Doug Ledford <dledford@redhat.com> > > -- > Doug Ledford <dledford@redhat.com> > GPG KeyID: B826A3330E572FDD > Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD
| ![\](/images/icornerr.gif) |