On Mon, 2015-03-02 at 13:30 -0800, Tyrel Datwyler wrote: > On 03/01/2015 08:19 PM, Cyril Bur wrote: > > On Fri, 2015-02-27 at 18:24 -0800, Tyrel Datwyler wrote: > >> During suspend/migration operation we must wait for the VASI state reported > >> by the hypervisor to become Suspending prior to making the ibm,suspend-me > >> RTAS call. Calling routines to rtas_ibm_supend_me() pass a vasi_state > >> variable > >> that exposes the VASI state to the caller. This is unnecessary as the > >> caller > >> only really cares about the following three conditions; if there is an > >> error > >> we should bailout, success indicating we have suspended and woken back up > >> so > >> proceed to device tree updated, or we are not suspendable yet so try > >> calling > >> rtas_ibm_suspend_me again shortly. > >> > >> This patch removes the extraneous vasi_state variable and simply uses the > >> return code to communicate how to proceed. We either succeed, fail, or get > >> -EAGAIN in which case we sleep for a second before trying to call > >> rtas_ibm_suspend_me again. > >> > >> u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32) > >> | be32_to_cpu(args.args[1]); > >> - rc = rtas_ibm_suspend_me(handle, &vasi_rc); > >> - args.rets[0] = cpu_to_be32(vasi_rc); > >> - if (rc) > >> + rc = rtas_ibm_suspend_me(handle); > >> + if (rc == -EAGAIN) > >> + args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE); > > > > (continuing on...) so perhaps here have > > rc = 0; > > else if (rc == -EIO) > > args.rets[0] = cpu_to_be32(-1); > > rc = 0; > > Which should keep the original behaviour, the last thing we want to do > > is break BE. > > The biggest problem here is we are making what basically equates to a > fake rtas call from drmgr which we intercept in ppc_rtas(). From there > we make this special call to rtas_ibm_suspend_me() to check VASI state > and do a bunch of other specialized work that needs to be setup prior to > making the actual ibm,suspend-me rtas call. Since, we are cheating PAPR > here I guess we can really handle it however we want. I chose to simply > fail the rtas call in the case where rtas_ibm_suspend_me() fails with > something other than -EAGAIN. In user space librtas will log errno for > the failure and return RTAS_IO_ASSERT to drmgr which in turn will log > that error and fail.
We don't want to change the return values of the syscall unless we absolutely have to. And I don't think that's the case here. Sure we think drmgr is the only thing that uses this crap, but we don't know for sure. cheers _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
