> -----Original Message----- > From: Stephen Hemminger [mailto:shemminger@xxxxxxxxxx] > Sent: Friday, July 01, 2011 12:45 AM > To: KY Srinivasan > Cc: Christoph Hellwig; devel@xxxxxxxxxxxxxxxxxxxxxx; gregkh@xxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxx > Subject: Re: [PATCH 00/40] Staging: hv: Driver cleanup > > On Fri, 1 Jul 2011 00:19:38 +0000 > KY Srinivasan <kys@xxxxxxxxxxxxx> wrote: > > > > > > > > -----Original Message----- > > > From: Stephen Hemminger [mailto:shemminger@xxxxxxxxxx] > > > Sent: Thursday, June 30, 2011 7:48 PM > > > To: KY Srinivasan > > > Cc: Christoph Hellwig; devel@xxxxxxxxxxxxxxxxxxxxxx; gregkh@xxxxxxx; linux- > > > kernel@xxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxx > > > Subject: Re: [PATCH 00/40] Staging: hv: Driver cleanup > > > > > > On Thu, 30 Jun 2011 23:32:34 +0000 > > > KY Srinivasan <kys@xxxxxxxxxxxxx> wrote: > > > > > > > > > > > > -----Original Message----- > > > > > From: Christoph Hellwig [mailto:hch@xxxxxxxxxxxxx] > > > > > Sent: Thursday, June 30, 2011 3:34 PM > > > > > To: KY Srinivasan > > > > > Cc: gregkh@xxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > > > > devel@xxxxxxxxxxxxxxxxxxxxxx; virtualization@xxxxxxxxxxxxxx > > > > > Subject: Re: [PATCH 00/40] Staging: hv: Driver cleanup > > > > > > > > > > On Wed, Jun 29, 2011 at 07:38:21AM -0700, K. Y. Srinivasan wrote: > > > > > > Further cleanup of the hv drivers: > > > > > > > > > > > > 1) Cleanup the reference counting mess for both stor and net > devices. > > > > > > > > > > I really don't understand the need for reference counting on the storage > > > > > side, especially now that you only have a SCSI driver. The SCSI > > > > > midlayer does proper counting on it's objects (Scsi_Host, scsi_device, > > > > > scsi_cmnd), so you'll get that for free given that SCSI drivers just > > > > > piggyback on the midlayer lifetime rules. > > > > > > > > > > For now your patches should probably go in as-is, but mid-term you > > > > > should be able to completely remove that code on the storage side. > > > > > > > > > > > > > Greg, > > > > > > > > I am thinking of going back to my original implementation where I had one > scsi > > > host > > > > per IDE device. This will certainly simply the code. Let me know what you > think. > > > If you > > > > agree with this approach, please drop this patch-set, I will send you a new > set > > > of patches. > > > > > > I think there ref counting on network devices is also unneeded > > > as long as the unregister logic handles RCU correctly. The network layer > > > calls the driver unregister routine after all packets are gone. > > On the networking side, what about incoming packets that may be racing > > with the device destruction. The current ref counting scheme deals with > > that case. > > Not sure how HV driver tells hypervisor to stop sending packets. But the > destructor is not called until after all other CPU's are done processing > packets from that device. The issue I was concerned is one where, on packet reception, we need to de-reference the ext field in the struct hv_device (this is the pointer to the net device and this could happen concurrently with the guest trying to shut-down the device. In the current code we deal with this condition. Regards, K. Y _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
