Messages in this thread | | | Date | Tue, 27 Sep 2022 02:37:21 +0100 | From | Al Viro <> | Subject | Re: [PATCH] vfio: Use filp instead of fd |
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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.
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