xen: remove gnttab_query_foreign_access()

stable inclusion
from linux-4.19.234
commit c900f34fc134cc75de431e16546f37bf7804a012

--------------------------------

Commit 1dbd11ca upstream.

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: NJuergen Gross <jgross@suse.com>
Reviewed-by: NJan Beulich <jbeulich@suse.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Reviewed-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NLaibin Qiu <qiulaibin@huawei.com>

drivers/xen/grant-table.c

@@ -134,13 +134,6 @@ 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 {
@@ -285,22 +278,6 @@ 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;
@@ -1307,7 +1284,6 @@ 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 = {
@@ -1319,7 +1295,6 @@ 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

@@ -118,8 +118,6 @@ 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
  */