> -----Original Message----- > From: Greg KH [mailto:[email protected]] > Sent: Tuesday, August 23, 2011 7:08 PM > To: KY Srinivasan > Cc: [email protected]; [email protected]; > [email protected]; [email protected]; Haiyang Zhang > Subject: Re: [PATCH 081/117] Staging: hv: vmbus: Introduce a lock to protect > the > ext field in hv_device > > On Fri, Jul 15, 2011 at 10:47:09AM -0700, K. Y. Srinivasan wrote: > > The current mechanism for handling references in broken. > > Introduce a lock to protect the ext field in hv_device. > > Why would that lock ever be needed? How can things change to this > pointer in different ways like you are thinking it could? Doesn't the > reference counting in the device itself handle this properly?
This is to deal with a potential race condition between the driver being unloaded and incoming traffic from the VMBUS side. The ext pointer is device specific (either pointing to a storage or a network device) and what we are protecting is the pointer being set to NULL from the unload side when we might have a racing access from the interrupt side (on the incoming vmbus traffic). Regards, K. Y _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
