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xen/grant-table: Support mappings required by blkback

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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>
[v1: Fix cleanpatch warnings]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
Daniel De Graaf 2011-12-14 15:12:11 -05:00 committed by Konrad Rzeszutek Wilk
parent 2946a52ac7
commit 7d17e84bb8
3 changed files with 8 additions and 21 deletions
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3
drivers/xen/gntdev.c
View file

@ -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) if (err)
return err; return err;

24
drivers/xen/grant-table.c
View file

@ -761,24 +761,10 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
(map_ops[i].host_addr & ~PAGE_MASK)); (map_ops[i].host_addr & ~PAGE_MASK));
mfn = pte_mfn(*pte); mfn = pte_mfn(*pte);
} else { } else {
/* If you really wanted to do this: mfn = PFN_DOWN(map_ops[i].dev_bus_addr);
* 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;
} }
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) if (ret)
return ret; return ret;
} }
@ -788,7 +774,7 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
EXPORT_SYMBOL_GPL(gnttab_map_refs); EXPORT_SYMBOL_GPL(gnttab_map_refs);
int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, 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; int i, ret;
@ -800,7 +786,7 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
return ret; return ret;
for (i = 0; i < count; i++) { 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) if (ret)
return ret; return ret;
} }

2
include/xen/grant_table.h
View file

@ -185,6 +185,6 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops, struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count); struct page **pages, unsigned int count);
int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops, 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__ */ #endif /* __ASM_GNTTAB_H__ */