[PATCH 3/4] mm: simplify device private page handling in hmm_range_fault

[Jason Gunthorpe]

On Thu, Mar 19, 2020 at 06:33:04PM -0700, Ralph Campbell wrote:

> > > +		.default_flags = dmirror_hmm_flags[HMM_PFN_VALID] |
> > > +				(write ? dmirror_hmm_flags[HMM_PFN_WRITE] : 0),
> > > +		.dev_private_owner = dmirror->mdevice,
> > > +	};
> > > +	int ret = 0;
> > 
> > > +static int dmirror_snapshot(struct dmirror *dmirror,
> > > +			    struct hmm_dmirror_cmd *cmd)
> > > +{
> > > +	struct mm_struct *mm = dmirror->mm;
> > > +	unsigned long start, end;
> > > +	unsigned long size = cmd->npages << PAGE_SHIFT;
> > > +	unsigned long addr;
> > > +	unsigned long next;
> > > +	uint64_t pfns[64];
> > > +	unsigned char perm[64];
> > > +	char __user *uptr;
> > > +	struct hmm_range range = {
> > > +		.pfns = pfns,
> > > +		.flags = dmirror_hmm_flags,
> > > +		.values = dmirror_hmm_values,
> > > +		.pfn_shift = DPT_SHIFT,
> > > +		.pfn_flags_mask = ~0ULL,
> > 
> > Same here, especially since this is snapshot
> > 
> > Jason
> 
> Actually, snapshot ignores pfn_flags_mask and default_flags.

Yes, so no reason to set them to not 0..

Jason