On Tue, Sep 27, 2022 at 01:21:50AM +0000, tomorrow Wang (王德明) wrote: > Hi > > Why kvm_vfio_group_add use file. > > struct file *filp; > ..... > filp = fget(fd); > > ..... > kvg->file = filp; This is why. Note that you've slightly misquoted it - it's actually either "stick into kvg->file" or "fput() it". > ...... > fput(filp); The reference we are getting here is non-transient one; it will be retained in shared data structures after we return from function - hell, after we return to userland.
