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Commit 0ae65f49 authored by Jennifer Herbert's avatar Jennifer Herbert Committed by David Vrabel
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x86/xen: require ballooned pages for grant maps 



Ballooned pages are always used for grant maps which means the
original frame does not need to be saved in page->index nor restored
after the grant unmap.

This allows the workaround in netback for the conflicting use of the
(unionized) page->index and page->pfmemalloc to be removed.

Signed-off-by: default avatarJennifer Herbert <jennifer.herbert@citrix.com>
Reviewed-by: default avatarStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent 0bb599fd

arch/x86/xen/p2m.c

+3 −2
Original line number Diff line number Diff line
@@ -682,9 +682,10 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops, 
		pfn = page_to_pfn(pages[i]);



		WARN_ON(PagePrivate(pages[i]));

		WARN(pfn_to_mfn(pfn) != INVALID_P2M_ENTRY, "page must be ballooned");



		SetPagePrivate(pages[i]);

		set_page_private(pages[i], mfn);

		pages[i]->index = pfn_to_mfn(pfn);



		if (unlikely(!set_phys_to_machine(pfn, FOREIGN_FRAME(mfn)))) {

			ret = -ENOMEM;
@@ -718,7 +719,7 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops, 
		set_page_private(pages[i], INVALID_P2M_ENTRY);

		WARN_ON(!PagePrivate(pages[i]));

		ClearPagePrivate(pages[i]);

		set_phys_to_machine(pfn, pages[i]->index);

		set_phys_to_machine(pfn, INVALID_P2M_ENTRY);

	}

	if (kunmap_ops)

		ret = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,

drivers/net/xen-netback/netback.c

+0 −6
Original line number Diff line number Diff line
@@ -1241,12 +1241,6 @@ static void xenvif_fill_frags(struct xenvif_queue *queue, struct sk_buff *skb) 
		/* Take an extra reference to offset network stack's put_page */

		get_page(queue->mmap_pages[pending_idx]);

	}

	/* FIXME: __skb_fill_page_desc set this to true because page->pfmemalloc

	 * overlaps with "index", and "mapping" is not set. I think mapping

	 * should be set. If delivered to local stack, it would drop this

	 * skb in sk_filter unless the socket has the right to use it.

	 */

	skb->pfmemalloc	= false;

}



static int xenvif_get_extras(struct xenvif_queue *queue,