diff options
Diffstat (limited to 'include/xen/grant_table.h')
| -rw-r--r-- | include/xen/grant_table.h | 30 |
1 files changed, 18 insertions, 12 deletions
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h index cb854df031ce..dfd5bf31cfb9 100644 --- a/include/xen/grant_table.h +++ b/include/xen/grant_table.h @@ -97,23 +97,32 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned long frame, * longer in use. Return 1 if the grant entry was freed, 0 if it is still in * use. */ -int gnttab_end_foreign_access_ref(grant_ref_t ref, int readonly); +int gnttab_end_foreign_access_ref(grant_ref_t ref); /* * Eventually end access through the given grant reference, and once that * access has been ended, free the given page too. Access will be ended * immediately iff the grant entry is not in use, otherwise it will happen * some time later. page may be 0, in which case no freeing will occur. + * 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. 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); +void gnttab_end_foreign_access(grant_ref_t ref, unsigned long page); -int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn); - -unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref); -unsigned long gnttab_end_foreign_transfer(grant_ref_t ref); - -int gnttab_query_foreign_access(grant_ref_t ref); +/* + * End access through the given grant reference, iff the grant entry is + * no longer in use. In case of success ending foreign access, the + * grant reference is deallocated. + * Return 1 if the grant entry was freed, 0 if it is still in use. + */ +int gnttab_try_end_foreign_access(grant_ref_t ref); /* * operations on reserved batches of grant references @@ -147,9 +156,6 @@ static inline void gnttab_page_grant_foreign_access_ref_one( readonly); } -void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid, - unsigned long pfn); - static inline void gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr, uint32_t flags, grant_ref_t ref, domid_t domid) |