[PATCH] xenbus: track user request id

Commit fd8aa9095a95 ("xen: optimize xenbus driver for multiple concurrent xenstore accesses") optimized xenbus concurrent accesses but in doing so may have broke UABI of /dev/xen/xenbus. Through /dev/xen/xenbus applications are in charge of exchange xenbus message exchange with the correct header

[PATCH] xenbus: track user request id

Commit fd8aa9095a95 ("xen: optimize xenbus driver for multiple concurrent xenstore accesses") optimized xenbus concurrent accesses but in doing so may have broke UABI of /dev/xen/xenbus. Through /dev/xen/xenbus applications are in charge of exchange xenbus message exchange with the correct header