Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Liam Howlett <liam.howlett@oracle.com>
To:     "maple-tree@lists.infradead.org" <maple-tree@lists.infradead.org>,
        "linux-mm@kvack.org" <linux-mm@kvack.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>
CC:     Yu Zhao <yuzhao@google.com>
Subject: [PATCH v12 57/69] mm/mlock: use vma iterator and maple state instead
 of vma linked list
Thread-Topic: [PATCH v12 57/69] mm/mlock: use vma iterator and maple state
 instead of vma linked list
Thread-Index: AQHYm97v8Wbn2YCWSEaq0szTMkwUqw==
Date:   Wed, 20 Jul 2022 02:18:01 +0000
Message-ID: <20220720021727.17018-58-Liam.Howlett@oracle.com>
References: <20220720021727.17018-1-Liam.Howlett@oracle.com>
In-Reply-To: <20220720021727.17018-1-Liam.Howlett@oracle.com>
Accept-Language: en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?iso-8859-1?Q?5bXhoCSA+irfC7D6wlI2yT7xcoMVz3owjisqjdMdyBej1IhliAi3k2TR+2?=
 =?iso-8859-1?Q?FbQWB/FurJ5uepnMx+Ql+tOXBetadvBX/alA5PolXyGMGNPRWtk64p02+R?=
 =?iso-8859-1?Q?8wi+v6lqYGRSh50Qw4tBRSDpjORd7H7WN44yrEC8F01qUe4yvnMT9/W7Nc?=
 =?iso-8859-1?Q?Wg2txKIkxGjsk468uALXNG9wtPQIaQJY1MH4u16tZ45nXNqprdDMi44Rx4?=
 =?iso-8859-1?Q?vNXNCRab7tS1ImeavPx8GN+609NudGFjQ+RYqA6Dlme9C/TdsR1769JJTl?=
 =?iso-8859-1?Q?+MiTPh0In7QW2o+j80YoVWtaUtWJUYrPSLIcZTnH4W0EHiG7GnEzQrDxJd?=
 =?iso-8859-1?Q?eOWa0Utg8xUpUcgnOJxfdfuz/kYV7Hk7NSY90DcAbBmdRubtYymbFl1hVw?=
 =?iso-8859-1?Q?cA1bspcyOBX3bHvqMywpYnVSQ0QqhpnpHbtDX1oeBjb3yBEEIaAWcorvbX?=
 =?iso-8859-1?Q?kfyixcaaBNRyCwCfWgclBiBmruIqtS36dFqCdmJNccWIU3fR2+S0xXT8Jg?=
 =?iso-8859-1?Q?uIUYKfb2QozwU7BrWwPSMsLdx2KMCFUtcPB9tLjG9Fe2/7e89Zmsn3zyyZ?=
 =?iso-8859-1?Q?pNuSnKtKZcW0iVQ1bKLF8EhLI6PoVUUS4hRP7s2LTx2t3jLBd+wOrZGz3P?=
 =?iso-8859-1?Q?/PSTsxrB7gPZhfG8E5VosgN6HWpvQSTAOCM0U+NweKMp0wvUnvKgFNHQXa?=
 =?iso-8859-1?Q?HNlyJblVwgbLB0DFdcn752uTqcMRGXPGVZbeJrz8lFBPMjDMmT61dvxWdV?=
 =?iso-8859-1?Q?uExNBZR2SjUHPPz0be03xB9EY+lRIrrLZW+vh5sUKlLO/aGsEej1w0br/q?=
 =?iso-8859-1?Q?pBgsYgD1j1J4u6mx5dNwArD8TkiStoxfD6Waw/ceh0wV23+zPji6xRT0za?=
 =?iso-8859-1?Q?aw7sfbqUMHEXgiITeqYW6Pwg/La3MTg3bvZxxhApQlHnXAPV5yIjR8fupI?=
 =?iso-8859-1?Q?ukt2iWjlh+d4XmERX5sYxXzFM31JvuRpIQRexO3fZ/LOFT9bkshCbMGR29?=
 =?iso-8859-1?Q?fM5o91Xlhe7+sjUfzbTB+qETY0w5bHTdHF01RuFSFKoxl1kzMNGJBidU4C?=
 =?iso-8859-1?Q?hgaP+JATa9XGV/RcsT99tX/g63nuSaAb8yCIMPMa7jxdHcdCbifwRnyfe1?=
 =?iso-8859-1?Q?zczMfblPiKkg4ENFwjvaHIoTXrJC7a96nOeNQ5xXP3oPlsKv58wSbfXEwr?=
 =?iso-8859-1?Q?L5cGi0dCWP5zGxpkOeWpTbGDEQ/tJjWQ3A50QQVo4edgUX0je/thWucI6m?=
 =?iso-8859-1?Q?XFAt9XarYDQFaUiWNmvR2fVZeJFV+ch7RkSfbmmZux9HRaaF9CrctwFtBb?=
 =?iso-8859-1?Q?m/0ZkHgVIXbpTmhfWqMtLqrg0p9dHXV0I0sywz/kppxNCO49ZYEs2ypF1W?=
 =?iso-8859-1?Q?3sR5d8u6jDqo4zRnEnKmJocOey4WFvODwNQ1Q4r47S0EVK7oS9HyTA6/qD?=
 =?iso-8859-1?Q?o0xGANFYET2vupdP9HLA/gldGv1NudIFWhAhvGv3WTfHMfcwMEL2QrXSim?=
 =?iso-8859-1?Q?dps6c5/MZbqZy4WeRLSlfWTfTUpqMc4QXxz60vLc17/irIla0g4QFExjHK?=
 =?iso-8859-1?Q?NtbZBJBn0qW4rb898qoG5USfRT9/sSmtyGUxHztZw0f2efO+2LTBSQQy/1?=
 =?iso-8859-1?Q?9J1X+/Juin/r0c1fblAy3ZILkA5FS5qkUrtyilKpVmOo88FVxsELU/Qg?=
 =?iso-8859-1?Q?=3D=3D?=
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: SN6PR10MB3022.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 0006fdf0-9983-41e1-26cc-08da69f62b30
X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Jul 2022 02:18:01.6331
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: Ifrby1QzpbY6x+CWAN33QedIqIpOMulgyGA1WZlz29EiHqsx0iG/3xWzYB8/Ku3K5EvA5Lwm/M9PKMlh7NDkvA==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BL3PR10MB6233
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1
 definitions=2022-07-19_10,2022-07-19_01,2022-06-22_01
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxscore=0 adultscore=0 phishscore=0
 mlxlogscore=999 spamscore=0 malwarescore=0 bulkscore=0 suspectscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2206140000
 definitions=main-2207200008
X-Proofpoint-GUID: AZ340EIytn0Pc1XWjVATJ5_-XT0nRgKU
X-Proofpoint-ORIG-GUID: AZ340EIytn0Pc1XWjVATJ5_-XT0nRgKU
X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED,
        DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,
        RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE autolearn=ham
        autolearn_force=no version=3.4.6
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on
        lindbergh.monkeyblade.net
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

Handle overflow checking in count_mm_mlocked_page_nr() differently.

Link: https://lkml.kernel.org/r/20220504011345.662299-42-Liam.Howlett@oracl=
e.com
Link: https://lkml.kernel.org/r/20220621204632.3370049-58-Liam.Howlett@orac=
le.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/mlock.c | 35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 716caf851043..c41604ba5197 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -471,6 +471,7 @@ static int apply_vma_lock_flags(unsigned long start, si=
ze_t len,
 	unsigned long nstart, end, tmp;
 	struct vm_area_struct *vma, *prev;
 	int error;
+	MA_STATE(mas, &current->mm->mm_mt, start, start);
=20
 	VM_BUG_ON(offset_in_page(start));
 	VM_BUG_ON(len !=3D PAGE_ALIGN(len));
@@ -479,13 +480,14 @@ static int apply_vma_lock_flags(unsigned long start, =
size_t len,
 		return -EINVAL;
 	if (end =3D=3D start)
 		return 0;
-	vma =3D find_vma(current->mm, start);
-	if (!vma || vma->vm_start > start)
+	vma =3D mas_walk(&mas);
+	if (!vma)
 		return -ENOMEM;
=20
-	prev =3D vma->vm_prev;
 	if (start > vma->vm_start)
 		prev =3D vma;
+	else
+		prev =3D mas_prev(&mas, 0);
=20
 	for (nstart =3D start ; ; ) {
 		vm_flags_t newflags =3D vma->vm_flags & VM_LOCKED_CLEAR_MASK;
@@ -505,7 +507,7 @@ static int apply_vma_lock_flags(unsigned long start, si=
ze_t len,
 		if (nstart >=3D end)
 			break;
=20
-		vma =3D prev->vm_next;
+		vma =3D find_vma(prev->vm_mm, prev->vm_end);
 		if (!vma || vma->vm_start !=3D nstart) {
 			error =3D -ENOMEM;
 			break;
@@ -526,24 +528,23 @@ static unsigned long count_mm_mlocked_page_nr(struct =
mm_struct *mm,
 {
 	struct vm_area_struct *vma;
 	unsigned long count =3D 0;
+	unsigned long end;
+	VMA_ITERATOR(vmi, mm, start);
=20
 	if (mm =3D=3D NULL)
 		mm =3D current->mm;
=20
-	vma =3D find_vma(mm, start);
-	if (vma =3D=3D NULL)
-		return 0;
-
-	for (; vma ; vma =3D vma->vm_next) {
-		if (start >=3D vma->vm_end)
-			continue;
-		if (start + len <=3D  vma->vm_start)
-			break;
+	/* Don't overflow past ULONG_MAX */
+	if (unlikely(ULONG_MAX - len < start))
+		end =3D ULONG_MAX;
+	else
+		end =3D start + len;
+	for_each_vma_range(vmi, vma, end) {
 		if (vma->vm_flags & VM_LOCKED) {
 			if (start > vma->vm_start)
 				count -=3D (start - vma->vm_start);
-			if (start + len < vma->vm_end) {
-				count +=3D start + len - vma->vm_start;
+			if (end < vma->vm_end) {
+				count +=3D end - vma->vm_start;
 				break;
 			}
 			count +=3D vma->vm_end - vma->vm_start;
@@ -659,6 +660,7 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, =
len)
  */
 static int apply_mlockall_flags(int flags)
 {
+	MA_STATE(mas, &current->mm->mm_mt, 0, 0);
 	struct vm_area_struct *vma, *prev =3D NULL;
 	vm_flags_t to_add =3D 0;
=20
@@ -679,7 +681,7 @@ static int apply_mlockall_flags(int flags)
 			to_add |=3D VM_LOCKONFAULT;
 	}
=20
-	for (vma =3D current->mm->mmap; vma ; vma =3D prev->vm_next) {
+	mas_for_each(&mas, vma, ULONG_MAX) {
 		vm_flags_t newflags;
=20
 		newflags =3D vma->vm_flags & VM_LOCKED_CLEAR_MASK;
@@ -687,6 +689,7 @@ static int apply_mlockall_flags(int flags)
=20
 		/* Ignore errors */
 		mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
+		mas_pause(&mas);
 		cond_resched();
 	}
 out:
--=20
2.35.1