Messages in this thread | | | From | tomorrow Wang (王德明) <> | Subject | Re: [PATCH] vfio: Use filp instead of fd | Date | Tue, 27 Sep 2022 01:25:51 +0000 |
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Hi,
Why kvm_vfio_group_add use file?
struct file *filp; ...... filp = fget(fd); ...... fput(filp);
>-------- > send: Al Viro <viro@ftp.linux.org.uk> 代表 Al Viro > 发送时间: 2022年9月27日 3:38 >to: Jason Gunthorpe <jgg@nvidia.com> > pbonzini@redhat.com; kvm@vger.kernel.org; linux-kernel@vger.kernel.org > sub: Re: [PATCH] vfio: Use filp instead of fd > > On Mon, Sep 26, 2022 at 02:07:43PM -0300, Jason Gunthorpe wrote: > > On Mon, Sep 26, 2022 at 02:54:07AM -0400, Deming Wang wrote: > > > The function of kvm_vfio_group_set_spapr_tce and kvm_vfio_group_del > > > use fd indirectly.But,it only be used for fd.file. So,we can > > > directly use the struct of file instead. > > > > > > Signed-off-by: Deming Wang <wangdeming@inspur.com> > > > --- > > > virt/kvm/vfio.c | 24 ++++++++++++------------ > > > 1 file changed, 12 insertions(+), 12 deletions(-) > > > > I thought about changing this too when I was looking at this. > > fdget/fdput includes a tiny micro-optimization that is legal here, > > however I doubt anyone cares about performance on this path. > > Microoptimization or not, I'd rather keep fget() limited to cases where we > really need it. There are non-trivial cases and having them easy to find is a > good thing. > > Again, the preferred way to do descriptor lookups is fdget() family, not fget() > one. [unhandled content-type:application/pkcs7-signature] | |