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 R. Howlett" <Liam.Howlett@oracle.com>
To:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        maple-tree@lists.infradead.org
Cc:     "Liam R. Howlett" <Liam.Howlett@Oracle.com>,
        Li Zetao <lizetao1@huawei.com>,
        "Liam R . Howlett" <Liam.Howlett@oracle.com>
Subject: [PATCH v4 37/49] mmap: Clean up mmap_region() unrolling
Date:   Fri, 20 Jan 2023 11:26:38 -0500
Message-Id: <20230120162650.984577-38-Liam.Howlett@oracle.com>
In-Reply-To: <20230120162650.984577-1-Liam.Howlett@oracle.com>
References: <20230120162650.984577-1-Liam.Howlett@oracle.com>
Content-Transfer-Encoding: 8bit
Content-Type: text/plain
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?ChpgXLPsbX4TG/TvBll/zpXNMrkYin3BYt4Z8ypAoCUUmRPeDcI+vJT7Qvx8?=
 =?us-ascii?Q?WEP5fKbubrOjc02UNX4s6toPz+4ILafZJqzOaJAzTuLfiueRDfokH9qktqyP?=
 =?us-ascii?Q?Diw6bcMcaU0k9VUdS7FBf+VyNn0nz4pZPWNBRDYqvBKBM+Zp3dJ9u7KGAbeR?=
 =?us-ascii?Q?3GVOwRHSUE/Fplli+ibT+d//QsztqP6scZmqc2isZi25YLYv47VAXkEOmzQW?=
 =?us-ascii?Q?2AnDDjYzsgw0n1xvPPtosdpmhCURzpdNcn8sGZLHJIqdbimhefPs9Hb4M5TZ?=
 =?us-ascii?Q?GuaEPlNHB//EJtgUZLbqT5TMX0I6nR1xw2Ag3EfUrgJE+0IfYkQC6cn/qYZd?=
 =?us-ascii?Q?ajTO7+YW8X0SHCyLrfB1iWyA0mEdBgfonwicfZJ5wO6gkhwY9+mJmylAI0gK?=
 =?us-ascii?Q?b6OdytMOfoe3QyQaKS4x0mtkBMK4LdmSL//YobdkioMNsEpF4+MlhruA0M0k?=
 =?us-ascii?Q?FkatMFFbWGNX99/yRrk+1KfotKiIL2PzfzQaLOdYEf1rJJk2yRcht38TU15d?=
 =?us-ascii?Q?myniaHjWSZwsx/2Pe7o71OvWqTWujnd9vgH67Iz6Sw2eYtk7o094kFGXCYn2?=
 =?us-ascii?Q?5RhRe5G3AhINIXx2yZ4LZD6k5ikmkM3BQIATwOsIPZJitXscc/Tp1LttMw+q?=
 =?us-ascii?Q?6QKeEZ7TkZX/6srvEJ7KIhisBumv0ho2C/nicdhmsKOTBTpzXp5lCfpNAtyX?=
 =?us-ascii?Q?InJQlE6bkOl61YfWOsiwcViOpxuqRW2BW4xWmJ75fmyytDZWlf1WudbDuwWm?=
 =?us-ascii?Q?3rnW8ffdS/KJcj5w2BWqZ0CQYO6ySC/EqXMR+PHnzoc9DC2b1KG2luYNacSN?=
 =?us-ascii?Q?HuDk0INApFKhz57bvXvQWzDdecogHWqCCzeLhLfQm016rgIUjfd4lQsk5wKe?=
 =?us-ascii?Q?vN8I1s4KY1sTYwTDFJAfwk0NHR/fLwDmKFRFuExBoM+FZDonL08RVIGhupb1?=
 =?us-ascii?Q?4veRoZCDBO9PL3/lL/IDnQMQQhAupfzAD9IlckUJlkWxUZx7yHtWj7qoaeDF?=
 =?us-ascii?Q?wOYIjl0cCvObzKaztsintQg5Xb6qykrfqvSH/L0J5FECXWiUXEpvYZD3Qpqk?=
 =?us-ascii?Q?KZjX3adoTeYQRkHzrJc5ZZYODyUAJ6GJ0yTEVMTRSCt2An7BO8pxj+hTS9V2?=
 =?us-ascii?Q?TKPNqpK4PpjoQ1/yvd1CjYHVGQnDRSRw7pQ7dTEgBzaQtxhWyfYJnVCpbpbz?=
 =?us-ascii?Q?/CzinQHnzhslNKu1ErQNKu6qPzgIu6/h3Qk8Y5cCx3KDyea9rbTt/t7UU91E?=
 =?us-ascii?Q?+BIvDoIfoGqTIZwEdNVo8Dxu7XnbhW+tWxz1HvfuQy0DB8wPWshM2wK+YkwN?=
 =?us-ascii?Q?zIYcDjBXYqvVAktzdFaXtXY2oESTy4MlNy1j7o3GVIUgR6L2nxWpSxfI2U8Y?=
 =?us-ascii?Q?e03FwmRACXCr9rHOKf5BYQuW/9iR/DP59ykTKmdTk2yw6pY9zatAtFQemzJy?=
 =?us-ascii?Q?uLlEZV/i4AohMLvgT5vz0C+5i9UGd6ZivFCqsZ0zGIsF33aFLPkFRspplDDB?=
 =?us-ascii?Q?tfaFd+6K8HeBT2eIU6oS759OeQWl61w99YZfJmFoHJla7aitLRvuiTWLNzQb?=
 =?us-ascii?Q?hNvhdI7prJ5+2NLo2c8rwF1aVaLYQiotNoF0u2/WZrsJT4+7lgbd6zgIkwwA?=
 =?us-ascii?Q?JQ=3D=3D?=
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 92a60486-397d-4a9e-789d-08dafb0367cd
X-MS-Exchange-CrossTenant-AuthSource: SN6PR10MB3022.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Jan 2023 16:28:47.3526
 (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: oTwZmoFrm6DTjBNEF52BXq/HXUk5aGzpy0Z9FeNXvp8O22Tw/GDPWrZU9uUPRcm2ijoK3gLkFwnvJF4UX81Hsg==
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SN7PR10MB6381
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.122.1
 definitions=2023-01-20_09,2023-01-20_01,2022-06-22_01
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 mlxlogscore=781
 malwarescore=0 mlxscore=0 phishscore=0 suspectscore=0 spamscore=0
 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1
 engine=8.12.0-2212070000 definitions=main-2301200157
X-Proofpoint-ORIG-GUID: aHyLiMUkDKpo14uM2Oyd3qR-NloLUsNb
X-Proofpoint-GUID: aHyLiMUkDKpo14uM2Oyd3qR-NloLUsNb
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: "Liam R. Howlett" <Liam.Howlett@Oracle.com>

Move logic of unrolling to the error path as apposed to duplicating it
within the function body.  This reduces the potential of missing an
update to one path when making changes.

Cc: Li Zetao <lizetao1@huawei.com>
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---
 mm/mmap.c | 45 ++++++++++++++++++---------------------------
 1 file changed, 18 insertions(+), 27 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index b6bedc07ef11..d9e2666d8059 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2604,12 +2604,11 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 		 * Expansion is handled above, merging is handled below.
 		 * Drivers should not alter the address of the VMA.
 		 */
-		if (WARN_ON((addr != vma->vm_start))) {
-			error = -EINVAL;
+		error = -EINVAL;
+		if (WARN_ON((addr != vma->vm_start)))
 			goto close_and_free_vma;
-		}
-		vma_iter_set(&vmi, addr);
 
+		vma_iter_set(&vmi, addr);
 		/*
 		 * If vm_flags changed after call_mmap(), we should try merge
 		 * vma again as we may succeed this time.
@@ -2646,25 +2645,13 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	}
 
 	/* Allow architectures to sanity-check the vm_flags */
-	if (!arch_validate_flags(vma->vm_flags)) {
-		error = -EINVAL;
-		if (file)
-			goto close_and_free_vma;
-		else if (vma->vm_file)
-			goto unmap_and_free_vma;
-		else
-			goto free_vma;
-	}
+	error = -EINVAL;
+	if (!arch_validate_flags(vma->vm_flags))
+		goto close_and_free_vma;
 
-	if (vma_iter_prealloc(&vmi)) {
-		error = -ENOMEM;
-		if (file)
-			goto close_and_free_vma;
-		else if (vma->vm_file)
-			goto unmap_and_free_vma;
-		else
-			goto free_vma;
-	}
+	error = -ENOMEM;
+	if (vma_iter_prealloc(&vmi))
+		goto close_and_free_vma;
 
 	if (vma->vm_file)
 		i_mmap_lock_write(vma->vm_file->f_mapping);
@@ -2723,14 +2710,18 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	return addr;
 
 close_and_free_vma:
-	if (vma->vm_ops && vma->vm_ops->close)
+	if (file && vma->vm_ops && vma->vm_ops->close)
 		vma->vm_ops->close(vma);
+
+	if (file || vma->vm_file) {
 unmap_and_free_vma:
-	fput(vma->vm_file);
-	vma->vm_file = NULL;
+		fput(vma->vm_file);
+		vma->vm_file = NULL;
 
-	/* Undo any partial mapping done by a device driver. */
-	unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end);
+		/* Undo any partial mapping done by a device driver. */
+		unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start,
+			     vma->vm_end);
+	}
 	if (file && (vm_flags & VM_SHARED))
 		mapping_unmap_writable(file->f_mapping);
 free_vma:
-- 
2.35.1