> -----Original Message----- > From: KY Srinivasan > Sent: Friday, August 7, 2015 2:28 > To: Dexuan Cui <decui@xxxxxxxxxxxxx>; David Miller <davem@xxxxxxxxxxxxx> > Cc: olaf@xxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; jasowang@xxxxxxxxxx; > driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > stephen@xxxxxxxxxxxxxxxxxx; stefanha@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; > apw@xxxxxxxxxxxxx; pebolle@xxxxxxxxxx; dan.carpenter@xxxxxxxxxx > Subject: RE: [PATCH V4 4/7] Drivers: hv: vmbus: add APIs to register callbacks to > process hvsock connection > > > -----Original Message----- > > From: Dexuan Cui > > Sent: Wednesday, August 5, 2015 9:54 PM > > To: David Miller <davem@xxxxxxxxxxxxx>; KY Srinivasan > > <kys@xxxxxxxxxxxxx> > > Cc: olaf@xxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; jasowang@xxxxxxxxxx; > > driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > stephen@xxxxxxxxxxxxxxxxxx; stefanha@xxxxxxxxxx; > > netdev@xxxxxxxxxxxxxxx; apw@xxxxxxxxxxxxx; pebolle@xxxxxxxxxx; > > dan.carpenter@xxxxxxxxxx > > Subject: RE: [PATCH V4 4/7] Drivers: hv: vmbus: add APIs to register callbacks > > to process hvsock connection > > > > > From: devel [mailto:driverdev-devel-bounces@xxxxxxxxxxxxxxxxxxxxxx] On > > Behalf > > > Of Dexuan Cui > > > Sent: Thursday, July 30, 2015 18:20 > > > To: David Miller <davem@xxxxxxxxxxxxx>; KY Srinivasan > > <kys@xxxxxxxxxxxxx> > > > Cc: olaf@xxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; jasowang@xxxxxxxxxx; > > > driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > > > stephen@xxxxxxxxxxxxxxxxxx; stefanha@xxxxxxxxxx; > > netdev@xxxxxxxxxxxxxxx; > > > apw@xxxxxxxxxxxxx; pebolle@xxxxxxxxxx; dan.carpenter@xxxxxxxxxx > > > Subject: RE: [PATCH V4 4/7] Drivers: hv: vmbus: add APIs to register > > callbacks to > > > process hvsock connection > > > > > > > From: David Miller > > > > Sent: Thursday, July 30, 2015 6:27 > > > > > > > > From: Dexuan Cui > > > > Date: Tue, 28 Jul 2015 05:35:11 -0700 > > > > > > > > > With the 2 APIs supplied by the VMBus driver, the coming net/hvsock > > driver > > > > > can register 2 callbacks and can know when a new hvsock connection is > > > > > offered by the host, and when a hvsock connection is being closed by > > the > > > > > host. > > > > > > > > > This is an extremely terrible interface. > > > > > > > > It's an opaque hook that allows on registry, and it's solve purpose > > > > is to allow a backdoor call into a foreign driver in another module. > > > > > > > > These are exactly the things we try to avoid. > > > > > > Hi David, > > > Thanks a lot for your reviewing and the suggestion! > > > > > > > Why not create a real abstraction where clients register an object, > > > > that can be contained as a sub-member inside of their own driver > > > > private, that provides the callback registry mechanism. > > > > Hi David, > > Can you please have a look at my below questions? > > > > I like your idea of a real abstraction. Your answer would definitely > > help me to implement that correctly. > > > > > Please pardon me for my inexperience. > > > Can you please be a bit more specific? > > > I guess maybe you're referencing a common design pattern in the driver > > > code, so an example in some existing driver would be the best. :-) > > > > > > "clients register an object " -- > > > does the "clients" mean the hvsock driver? > > > and the "object" means the 2 callbacks? > > > > > > IMHO, here the vmbus driver has to synchronously pass the 2 events > > > to the hvsock driver, so a "backdoor call into the hvsock driver" is > > > inevitable anyway? > > > > > > e.g., in the path vmbus_process_offer() -> hvsock_process_offer(), the > > > return value of the latter is important to the former, because on error > > > the former needs to clean up some internal states of the vmbus driver > > (that > > > is, the "goto err_deq_chan"). > > > > > > > > > > That way you can register multiple clients, do things like allow > > > > AF_PACKET capturing of vmbus traffic, etc. > > > > > > I thought AF_PACKET can only capture IP packetsor Ethernet frames. > > > Can it be used to capture AF_UNIX packet? > > > If yes, I suppose we can consider making it work for AF_HYPERV too, > > > if people ask for that. > > > > > Dexuan, > > The notion of a channel on Hyper-V has been mapped to a device on Linux and > the mechanism we have > had of notifying the driver of the creation of the channel was through > registering this device with the kernel > (vmbus_device_create). The first exception to this was when we introduced > multi-channel support that broke > the assumption of this one to one mapping between the channel and Linux > device. In the case of the sub-channels, > we handled the driver notification issue via the sub-channel callback that the > driver registers at the point of > opening the channel. Perhaps we could make the sub-channel handling > mechanism more generic to handle the case > of VMSOCK as well? > > K. Y Good suggestion! Let me think this over and make a new patch. Thanks, -- Dexuan _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
