On Thu, 10 Oct 2013 15:59:28 -0600 Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > On Fri, May 17, 2013 at 3:42 PM, Joe Lawrence <joe.lawrence@xxxxxxxxxxx> wrote: > > On Fri, 17 May 2013 09:29:06 -0600 > > Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > > > >> [+cc linux-pci] > >> > >> On Wed, May 15, 2013 at 11:29 AM, Joe Lawrence > >> <joe.lawrence@xxxxxxxxxxx> wrote: > >> > From 84ac7a35ebd61e84d4254eae78bb967de17254c2 Mon Sep 17 00:00:00 > >> > 2001 From: Joe Lawrence <joe.lawrence@xxxxxxxxxxx> > >> > Date: Wed, 15 May 2013 12:52:31 -0400 > >> > Subject: [PATCH] mpt2sas,mpt3sas: make watchdog instantiated device > >> > removal safe > >> > > >> > Calling pci_stop_and_remove_bus_device from a SCSI LLD may introduce > >> > device removal races with PCI callback functions. > >> > > >> > Simplify the mpt2sas watchdog mechanism by separating PCI device > >> > removal from SCSI midlayer detachment. When the watchdog wishes to > >> > remove a SCSI device from the topology, detach from the SCSI > >> > midlayer, leaving the PCI device alone. Adjust various pci_driver > >> > callbacks to account for a potentially SCSI detached PCI device. > >> > >> I don't know the details of the SCSI detachment, but this approach > >> looks much cleaner to me. > > > > Thanks for commenting, Bjorn. I think this approach more closely > > represents what this watchdog is trying to accomplish. > > > > Off list, Sreekanth from LSI tested and noticed a few issues with this > > patch: > > > > - mpt2sas_base_stop_watchdog is called twice: The call from > > mpt2sas_base_detach is safe, but now unnecessary (as a call was > > added earlier up in the PCI driver callbacks to ensure that the > > watchdog was out of the way.) This second invocation can be removed. > > > > - If the watchdog detects a bad IOC, the watchdog remains running: > > The watchdog workqueue isn't cleaned up until > > mpt2sas_base_stop_watchdog is called, so in the case that the > > watchdog removes the device from SCSI topo, the workqueue will > > remain unused until PCI .remove/.shutdown cleans it up. Perhaps a > > single watchdog that iterates over all adapters would be simpler? > > > > Finally, if SCSI topo detachment is all that is interesting here, would > > it make more sense to move the watchdog into the MPT "scsi" code? I > > haven't looked at the code yet, but this might make an MPT fusion patch > > easier (due to dependencies between its "scsi" and "base" modules). > > Hi Joe, > > I noticed this when looking through old email. I can't remember if > anything happened with this. It seems like nice work; did it go > anywhere? Hello Bjorn, Sorry for the late reply, I was on vacation last week. This patchset started as an attempt to push upstream some of the changes that Stratus makes to the fusion/mpt* drivers. I had hoped to come up with a patchset that fixed hotplug vs. watchdog removal in each of the three LSI drivers. Unfortunately this was more of a spare time project and other work took priority. There is a chance that Stratus maybe revisiting the fusion driver in the near future. I will keep this patchset in mind if that happens. Regards, -- Joe -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
