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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Juergen Gross <jgross@suse.com>,
        Jan Beulich <jbeulich@suse.com>
Subject: [PATCH 5.16 48/53] xen: remove gnttab_query_foreign_access()
Date:   Thu, 10 Mar 2022 15:09:53 +0100
Message-Id: <20220310140813.215631684@linuxfoundation.org>
In-Reply-To: <20220310140811.832630727@linuxfoundation.org>
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From: Juergen Gross <jgross@suse.com>

Commit 1dbd11ca75fe664d3e54607547771d021f531f59 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: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/xen/grant-table.c |   25 -------------------------
 include/xen/grant_table.h |    2 --
 2 files changed, 27 deletions(-)

--- a/drivers/xen/grant-table.c
+++ b/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
 }
 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
 	.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
 	.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)
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -125,8 +125,6 @@ int gnttab_grant_foreign_transfer(domid_
 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
  */