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From: Matthew Wilcox <willy@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>,
	Dan Carpenter <dan.carpenter@linaro.org>,
	linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	"Liam R. Howlett" <liam.howlett@oracle.com>,
	Laurent Dufour <ldufour@linux.ibm.com>,
	Michel Lespinasse <michel@lespinasse.org>,
	Jerome Glisse <jglisse@google.com>,
	Michal Hocko <mhocko@suse.com>, Vlastimil Babka <vbabka@suse.cz>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Peter Xu <peterx@redhat.com>,
	Dimitri Sivanich <dimitri.sivanich@hpe.com>,
	Mike Travis <mike.travis@hpe.com>,
	Steve Wahl <steve.wahl@hpe.com>
Subject: Re: [bug report] mm: replace vma->vm_flags direct modifications with modifier calls
Date: Wed, 12 Jul 2023 20:34:10 +0100	[thread overview]
Message-ID: <ZK8AMisNxhF/bJsU@casper.infradead.org> (raw)
In-Reply-To: <ZK710ZpILgFV5CLH@casper.infradead.org>

On Wed, Jul 12, 2023 at 07:49:53PM +0100, Matthew Wilcox wrote:
> @@ -964,9 +966,12 @@ vm_fault_t gru_fault(struct vm_fault *vmf)
>  		}
>  		gru_load_context(gts);
>  		paddr = gseg_physical_address(gts->ts_gru, gts->ts_ctxnum);
> -		remap_pfn_range(vma, vaddr & ~(GRU_GSEG_PAGESIZE - 1),
> -				paddr >> PAGE_SHIFT, GRU_GSEG_PAGESIZE,
> -				vma->vm_page_prot);
> +
> +		pte = pfn_pte(paddr / PAGE_SIZE, vma->vm_page_prot);
> +		ptep = vmf->pte - (vaddr % GRU_GSEG_PAGESIZE) / PAGE_SIZE;
> +		set_ptes(vma->vm_mm, vaddr & ~(GRU_GSEG_PAGESIZE - 1),
> +				ptep, pte_mkspecial(pte),
> +				GRU_GSEG_PAGESIZE / PAGE_SIZE);
>  	}

Argh, no, this is wrong.  The page table isn't mapped at this point.
What we want is a cross between vmf_insert_pfn() and vm_insert_pages().
Let me add that ...



  parent reply	other threads:[~2023-07-12 19:34 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-11  7:21 [bug report] mm: replace vma->vm_flags direct modifications with modifier calls Dan Carpenter
2023-07-11 21:55 ` Suren Baghdasaryan
2023-07-11 22:21   ` Matthew Wilcox
2023-07-11 23:45     ` Suren Baghdasaryan
2023-07-12  7:35       ` David Hildenbrand
2023-07-12 15:01         ` Suren Baghdasaryan
2023-07-12 15:52           ` Matthew Wilcox
2023-07-12 15:55             ` David Hildenbrand
2023-07-12 16:03               ` Suren Baghdasaryan
2023-07-12 18:49               ` Matthew Wilcox
2023-07-12 18:52                 ` David Hildenbrand
2023-07-12 19:48                   ` Suren Baghdasaryan
2023-07-17  6:13                     ` Yan Zhao
2023-07-17 16:18                       ` Suren Baghdasaryan
2023-07-18  0:27                         ` Yan Zhao
2023-07-18 16:27                           ` Suren Baghdasaryan
2023-07-12 19:34                 ` Matthew Wilcox [this message]
2023-07-17 19:54                   ` Dimitri Sivanich

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