Commit 7d17e84b authored by Daniel De Graaf's avatar Daniel De Graaf Committed by Konrad Rzeszutek Wilk
Browse files

xen/grant-table: Support mappings required by blkback 



Add support for mappings without GNTMAP_contains_pte. This was not
supported because the unmap operation assumed that this flag was being
used; adding a parameter to the unmap operation to allow the PTE
clearing to be disabled is sufficient to make unmap capable of
supporting either mapping type.

Signed-off-by: default avatarDaniel De Graaf <dgdegra@tycho.nsa.gov>
[v1: Fix cleanpatch warnings]
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 2946a52a

drivers/xen/gntdev.c

+2 −1
Original line number Diff line number Diff line
@@ -314,7 +314,8 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages) 
		}

	}



	err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages + offset, pages);

	err = gnttab_unmap_refs(map->unmap_ops + offset, map->pages + offset,

				pages, true);

	if (err)

		return err;

drivers/xen/grant-table.c

+5 −19
Original line number Diff line number Diff line
@@ -761,24 +761,10 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, 
				(map_ops[i].host_addr & ~PAGE_MASK));

			mfn = pte_mfn(*pte);

		} else {

			/* If you really wanted to do this:

			 * mfn = PFN_DOWN(map_ops[i].dev_bus_addr);

			 *

			 * The reason we do not implement it is b/c on the

			 * unmap path (gnttab_unmap_refs) we have no means of

			 * checking whether the page is !GNTMAP_contains_pte.

			 *

			 * That is without some extra data-structure to carry

			 * the struct page, bool clear_pte, and list_head next

			 * tuples and deal with allocation/delallocation, etc.

			 *

			 * The users of this API set the GNTMAP_contains_pte

			 * flag so lets just return not supported until it

			 * becomes neccessary to implement.

			 */

			return -EOPNOTSUPP;

			mfn = PFN_DOWN(map_ops[i].dev_bus_addr);

		}

		ret = m2p_add_override(mfn, pages[i], &kmap_ops[i]);

		ret = m2p_add_override(mfn, pages[i], kmap_ops ?

				       &kmap_ops[i] : NULL);

		if (ret)

			return ret;

	}
@@ -788,7 +774,7 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, 
EXPORT_SYMBOL_GPL(gnttab_map_refs);



int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,

		      struct page **pages, unsigned int count)

		      struct page **pages, unsigned int count, bool clear_pte)

{

	int i, ret;
@@ -800,7 +786,7 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, 
		return ret;



	for (i = 0; i < count; i++) {

		ret = m2p_remove_override(pages[i], true /* clear the PTE */);

		ret = m2p_remove_override(pages[i], clear_pte);

		if (ret)

			return ret;

	}

include/xen/grant_table.h

+1 −1
Original line number Diff line number Diff line
@@ -185,6 +185,6 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops, 
		    struct gnttab_map_grant_ref *kmap_ops,

		    struct page **pages, unsigned int count);

int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,

		      struct page **pages, unsigned int count);

		      struct page **pages, unsigned int count, bool clear_pte);



#endif /* __ASM_GNTTAB_H__ */

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