xen: remove gnttab_query_foreign_access()

Remove gnttab_query_foreign_access(), as it is unused and unsafe to
use.

All previous use cases assumed a grant would not be in use after
gnttab_query_foreign_access() returned 0. This information is useless
in best case, as it only refers to a situation in the past, which could
have changed already.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

drivers/xen/grant-table.c

@@ -133,13 +133,6 @@ struct gnttab_ops {
  * return the frame.
  */
  unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);
- /*
- * Query the status of a grant entry. Ref parameter is reference of
- * queried grant entry, return value is the status of queried entry.
- * Detailed status(writing/reading) can be gotten from the return value
- * by bit operations.
- */
- int (*query_foreign_access)(grant_ref_t ref);
 };
 
 struct unmap_refs_callback_data {
@@ -284,22 +277,6 @@ int gnttab_grant_foreign_access(domid_t domid, unsigned long frame,
 }
 EXPORT_SYMBOL_GPL(gnttab_grant_foreign_access);
 
-static int gnttab_query_foreign_access_v1(grant_ref_t ref)
-{
- return gnttab_shared.v1[ref].flags & (GTF_reading|GTF_writing);
-}
-
-static int gnttab_query_foreign_access_v2(grant_ref_t ref)
-{
- return grstatus[ref] & (GTF_reading|GTF_writing);
-}
-
-int gnttab_query_foreign_access(grant_ref_t ref)
-{
- return gnttab_interface->query_foreign_access(ref);
-}
-EXPORT_SYMBOL_GPL(gnttab_query_foreign_access);
-
 static int gnttab_end_foreign_access_ref_v1(grant_ref_t ref, int readonly)
 {
  u16 flags, nflags;
@@ -1427,7 +1404,6 @@ static const struct gnttab_ops gnttab_v1_ops = {
  .update_entry = gnttab_update_entry_v1,
  .end_foreign_access_ref = gnttab_end_foreign_access_ref_v1,
  .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v1,
- .query_foreign_access = gnttab_query_foreign_access_v1,
 };
 
 static const struct gnttab_ops gnttab_v2_ops = {
@@ -1439,7 +1415,6 @@ static const struct gnttab_ops gnttab_v2_ops = {
  .update_entry = gnttab_update_entry_v2,
  .end_foreign_access_ref = gnttab_end_foreign_access_ref_v2,
  .end_foreign_transfer_ref = gnttab_end_foreign_transfer_ref_v2,
- .query_foreign_access = gnttab_query_foreign_access_v2,
 };
 
 static bool gnttab_need_v2(void)

include/xen/grant_table.h

@@ -125,8 +125,6 @@ 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);
-
 /*
  * operations on reserved batches of grant references
  */