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:   Sidhartha Kumar <sidhartha.kumar@oracle.com>
To:     linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc:     akpm@linux-foundation.org, songmuchun@bytedance.com,
        mike.kravetz@oracle.com, willy@infradead.org, vbabka@suse.cz,
        william.kucharski@oracle.com, dhowells@redhat.com,
        peterx@redhat.com, arnd@arndb.de, ccross@google.com,
        hughd@google.com, ebiederm@xmission.com,
        Sidhartha Kumar <sidhartha.kumar@oracle.com>
Subject: [PATCH 2/7] mm: add private field of first tail to struct page and struct folio
Date:   Mon, 29 Aug 2022 16:00:09 -0700
Message-Id: <20220829230014.384722-3-sidhartha.kumar@oracle.com>
In-Reply-To: <20220829230014.384722-1-sidhartha.kumar@oracle.com>
References: <20220829230014.384722-1-sidhartha.kumar@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?7naYemPqoh8GqbNLMgR9vTFESOQQahzbOtFeP4wA+a9T8HLTeQAfUgqJdij7?=
 =?us-ascii?Q?mumUZld7NQQe5WXD4UThqECdPUtsqYXliCCeTQb43nb+18SzWvh8zlVbceCF?=
 =?us-ascii?Q?zofoVyYQxhAzqiyxQ/FyHv3zkI64eSW1SK/1G5f+FPT09lKXZYT7+rP4j0Qf?=
 =?us-ascii?Q?SLdLgzsi5aHfSsg2m6XALeljOY9WNrHQXyx4Zmm6fn372mHVgnh4DD/ZptkC?=
 =?us-ascii?Q?5dgMOjNQLezDFiVL5xecTlHQKtc4DVv9PvT5/oJguXq79FstgOCeXX4dvBli?=
 =?us-ascii?Q?ldMT7zo/RgyRvf+CYQRtBC0jeJKAbhsYZBbHidsN6+dJSXsy3bvpi31LLoha?=
 =?us-ascii?Q?x0BZK/6t6HKlJ6iuKgfKLum+Sd+LbbYMergUD/dFIWFI3S9DsoLn6Qfr40CS?=
 =?us-ascii?Q?J1J0EkvBgL1IS4d+0z74uYkHS716sovUg3M9xi1FNDfjNTw/V7JCL1nG+oQn?=
 =?us-ascii?Q?SPnea2o/2bw/Gmg/9yuuSiCJlHx6b0k5WQo6dnEFtoJrMxsNHZ7/DfrLzDPW?=
 =?us-ascii?Q?NUxRTKQNsvKSybDGxIZDDNpsZICDGaBvJyK3gQDHcB+u66raWQYv6JgGLZv0?=
 =?us-ascii?Q?xHXrxb51qpfM8Hkpg/KYlw4MxsHAFPt8jLcsjE5cXdvTZKy1kzXlUmjhMGWe?=
 =?us-ascii?Q?IIgUZdcxYOsudP4pQgpaXIiG/IxGPIYkoKvL5PxuNlo1arWhDOVdHxBWfU87?=
 =?us-ascii?Q?oBfugu+iYDAEvC1fTivwnA+hcxcv0/NkNSJc/3KjgsKpdrxlIjpV8WT+pLwd?=
 =?us-ascii?Q?VWgQOdw0+NkCWcj440VTSyqPsdyq070xOXU2q2JZqgb5VZhdwSY5ALhb087o?=
 =?us-ascii?Q?XVIny7ouVsdcb5sSRcs5aKwXg522ODGndI57PyJPi5YoeX4pybA2R6yQRFL8?=
 =?us-ascii?Q?NFOKdvxPkkp5V4H/mYWk0p0GD+qocBKGa6FDftltrjMeFNHmopJ0iieOUnLd?=
 =?us-ascii?Q?KJbsDklxDx67auPeFwz1F6WIx4d0I6KeKkckkrD4PkfXOkZvDV+Pn+lE7K2T?=
 =?us-ascii?Q?yj03+40X7OPwkOktF55lipuiwv4s0df0APQCKAoPTHTuzYorkmJT3NeXL49K?=
 =?us-ascii?Q?IliuT7vVmOIxfmCttQMUzrOo3emYInWq8mWIc2Ju3UXloAlFSutl7hhIIH83?=
 =?us-ascii?Q?gg3vk4TCOSFfAaBUaPEDzDJ0lwaOwqxHxshdfOXoo7L7dvO64ohPf8pt8H2o?=
 =?us-ascii?Q?+pKlspx7E11COrfkF8HOL5iSI36pwxakKft+UuaZiBDSsBt8IN6m0KsNnxsw?=
 =?us-ascii?Q?I2xFurl8EdbHJUM9WTwJ26TN7KaZsrHJNrhd7r23lNT5ozsTfXIHOIua/jej?=
 =?us-ascii?Q?YjAmnGDEijmH2PO0ILmoDeDx0Jgl3qf12nEXHKsTbxE49Rdz5iAkHLyrl9qR?=
 =?us-ascii?Q?dsF9zK2S3a4jAjmKssIWtAp0X7DPTpYMpfRUJ42eQk+TlTtDbfZsCu1IucVY?=
 =?us-ascii?Q?zdLnSjehTX9ixNT3FUBHFnr3kORsf7FXZuBrV6djz7K0nEZTECCu8eYuEGrN?=
 =?us-ascii?Q?jiD3eclzAR6E/G09CZ7WbB14Rw9T5G0qLRi+QxrlEvqsBxJKuGH+3lfzs9Rr?=
 =?us-ascii?Q?uq5SQP3hl/JgE03Y94RuIkCnaH2+0laXqMuALvRQ1CB6qUxOPA+PWMPSAy8y?=
 =?us-ascii?Q?qg=3D=3D?=
X-OriginatorOrg: oracle.com
X-MS-Exchange-CrossTenant-Network-Message-Id: a154b1e6-e4f0-4604-a2f5-08da8a124fea
X-MS-Exchange-CrossTenant-AuthSource: CH0PR10MB5113.namprd10.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Aug 2022 23:00:48.2417
 (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: WWGNNWuJZgxUakLkc6QdS725Y1dAiPbwuZqm0YuPYPsFeQ/knLjVBBsQ/RnU67vPHWnBx5E0fK2JZgubTw9QoYlQpqG/uE0NMvTubqBk9W8=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR10MB3736
X-Proofpoint-Virus-Version: vendor=baseguard
 engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.517,FMLib:17.11.122.1
 definitions=2022-08-29_11,2022-08-25_01,2022-06-22_01
X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 mlxscore=0 malwarescore=0
 suspectscore=0 spamscore=0 adultscore=0 mlxlogscore=999 bulkscore=0
 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2207270000
 definitions=main-2208290101
X-Proofpoint-ORIG-GUID: KQJrvUl2luR0B9OAojGzTamAzui-Qp5w
X-Proofpoint-GUID: KQJrvUl2luR0B9OAojGzTamAzui-Qp5w
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,T_SCC_BODY_TEXT_LINE
        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

Allows struct folio to store hugetlb metadata that is contained in the
private field of the first tail page.

Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
---
 include/linux/mm_types.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8a9ee9d24973..726c5304172c 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -144,6 +144,7 @@ struct page {
 #ifdef CONFIG_64BIT
 			unsigned int compound_nr; /* 1 << compound_order */
 #endif
+			unsigned long _private_1;
 		};
 		struct {	/* Second tail page of compound page */
 			unsigned long _compound_pad_1;	/* compound_head */
@@ -251,6 +252,7 @@ struct page {
  * @_total_mapcount: Do not use directly, call folio_entire_mapcount().
  * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
  * @_folio_nr_pages: Do not use directly, call folio_nr_pages().
+ * @_private_1: Do not use directly, call folio_get_private_1().
  *
  * A folio is a physically, virtually and logically contiguous set
  * of bytes.  It is a power-of-two in size, and it is aligned to that
@@ -298,6 +300,8 @@ struct folio {
 #ifdef CONFIG_64BIT
 	unsigned int _folio_nr_pages;
 #endif
+	unsigned long _private_1;
+
 };
 
 #define FOLIO_MATCH(pg, fl)						\
@@ -325,6 +329,7 @@ FOLIO_MATCH(compound_mapcount, _total_mapcount);
 FOLIO_MATCH(compound_pincount, _pincount);
 #ifdef CONFIG_64BIT
 FOLIO_MATCH(compound_nr, _folio_nr_pages);
+FOLIO_MATCH(_private_1, _private_1);
 #endif
 #undef FOLIO_MATCH
 
@@ -370,6 +375,16 @@ static inline void *folio_get_private(struct folio *folio)
 	return folio->private;
 }
 
+static inline void folio_set_private_1(struct folio *folio, unsigned long private)
+{
+	folio->_private_1 = private;
+}
+
+static inline unsigned long folio_get_private_1(struct folio *folio)
+{
+	return folio->_private_1;
+}
+
 struct page_frag_cache {
 	void * va;
 #if (PAGE_SIZE < PAGE_FRAG_CACHE_MAX_SIZE)
-- 
2.31.1