Mailing List Archive

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: Daniel De Graaf <dgdegra@tycho.nsa.gov>
---
drivers/xen/gntdev.c | 3 ++-
drivers/xen/grant-table.c | 23 ++++-------------------
include/xen/grant_table.h | 2 +-
3 files changed, 7 insertions(+), 21 deletions(-)

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index afca14d..65bff07 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -312,7 +312,8 @@ 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;

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index bf1c094..a02d139 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -472,24 +472,9 @@ 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;
}
@@ -499,7 +484,7 @@ 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;

@@ -511,7 +496,7 @@ 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;
}
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 11e2dfc..37da54d 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -158,6 +158,6 @@ 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__ */
--
1.7.7.4


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