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

[Jason Gunthorpe]

On Tue, Mar 17, 2020 at 04:14:31PM -0700, Ralph Campbell wrote:

> +static int dmirror_fault(struct dmirror *dmirror, unsigned long start,
> +			 unsigned long end, bool write)
> +{
> +	struct mm_struct *mm = dmirror->mm;
> +	unsigned long addr;
> +	uint64_t pfns[64];
> +	struct hmm_range range = {
> +		.notifier = &dmirror->notifier,
> +		.pfns = pfns,
> +		.flags = dmirror_hmm_flags,
> +		.values = dmirror_hmm_values,
> +		.pfn_shift = DPT_SHIFT,
> +		.pfn_flags_mask = ~(dmirror_hmm_flags[HMM_PFN_VALID] |
> +				    dmirror_hmm_flags[HMM_PFN_WRITE]),

Since pfns is not initialized pfn_flags_mask should be 0.

> +		.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