diff options
Diffstat (limited to 'include/xen/grant_table.h')
| -rw-r--r-- | include/xen/grant_table.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index ab9e692a0ef4..c9fea9389ebe 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -107,7 +107,12 @@ int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly); * Note that the granted page might still be accessed (read or write) by the * other side after gnttab_end_foreign_access() returns, so even if page was * specified as 0 it is not allowed to just reuse the page for other - * purposes immediately. + * purposes immediately. gnttab_end_foreign_access() will take an additional + * reference to the granted page in this case, which is dropped only after + * the grant is no longer in use. + * This requires that multi page allocations for areas subject to + * gnttab_end_foreign_access() are done via alloc_pages_exact() (and freeing + * via free_pages_exact()) in order to avoid high order pages. */ void gnttab_end_foreign_access(grant_ref_t ref, int readonly, unsigned long page); |