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Fri, 04 Apr 2025 02:19:12 +0000 (GMT) Received: from pps.filterd (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.2/8.18.1.2) with ESMTP id 5340e3TA017325; Fri, 4 Apr 2025 02:19:11 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 45t2pspj97-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 04 Apr 2025 02:19:10 +0000 Received: from iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 5342H8ge030074; Fri, 4 Apr 2025 02:19:10 GMT Received: from localhost.localdomain (ca-dev60.us.oracle.com [10.129.136.27]) by iadpaimrmta02.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 45t2pspj73-3; Fri, 04 Apr 2025 02:19:10 +0000 From: Anthony Yznaga To: akpm@linux-foundation.org, willy@infradead.org, markhemm@googlemail.com, viro@zeniv.linux.org.uk, david@redhat.com, khalid@kernel.org Cc: anthony.yznaga@oracle.com, andreyknvl@gmail.com, dave.hansen@intel.com, luto@kernel.org, brauner@kernel.org, arnd@arndb.de, ebiederm@xmission.com, catalin.marinas@arm.com, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhiramat@kernel.org, rostedt@goodmis.org, vasily.averin@linux.dev, xhao@linux.alibaba.com, pcc@google.com, neilb@suse.de, maz@kernel.org Subject: [PATCH v2 02/20] mm/mshare: pre-populate msharefs with information file Date: Thu, 3 Apr 2025 19:18:44 -0700 Message-ID: <20250404021902.48863-3-anthony.yznaga@oracle.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250404021902.48863-1-anthony.yznaga@oracle.com> References: <20250404021902.48863-1-anthony.yznaga@oracle.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1095,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-04-04_01,2025-04-03_03,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 phishscore=0 bulkscore=0 mlxscore=0 spamscore=0 adultscore=0 suspectscore=0 mlxlogscore=999 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2502280000 definitions=main-2504040014 X-Proofpoint-ORIG-GUID: 5EX2FvNmxhkCoLSUIS8A4xTErMV4vc5S X-Proofpoint-GUID: 5EX2FvNmxhkCoLSUIS8A4xTErMV4vc5S X-Stat-Signature: qo69awpaqcbrsuiwp41d59ripyoh4qtx X-Rspam-User: X-Rspamd-Queue-Id: 0DCA014000C X-Rspamd-Server: rspam08 X-HE-Tag: 1743733167-422427 X-HE-Meta: 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 16L8kv6f 5mRZGMH4bDb0LixhfyvrRnw8QBuSgEouGUwfJ3e/tHHe2fPbPE9NCCkTbh6/gyDVySH+FNy7G0ZcGoWIkqjJPZBTv5qTJa46m9F2UAgdFSiZGc9BmAI46utRPl+ymq9DyXTlE8jddcwBZlLcLEez1CUDXIlZAvLHnl+TtzXIpauesVO1OqJPTgmjwxmXv8rSkfxH38vifruwYXg+UDvFAInsLMu7AqSwXTldABxuyGTOITiK9Rs7rSo26WiBbiIHKTIhJzK2VQHrt7T0= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Khalid Aziz Users of mshare need to know the size and alignment requirement for shared regions. Pre-populate msharefs with a file, mshare_info, that provides this information. For now, pagetable sharing is hardcoded to be at the PUD level. Signed-off-by: Khalid Aziz Signed-off-by: Anthony Yznaga --- mm/mshare.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 75 insertions(+), 2 deletions(-) diff --git a/mm/mshare.c b/mm/mshare.c index f703af49ec81..d666471bc94b 100644 --- a/mm/mshare.c +++ b/mm/mshare.c @@ -17,18 +17,74 @@ #include #include +const unsigned long mshare_align = P4D_SIZE; + static const struct file_operations msharefs_file_operations = { .open = simple_open, }; +struct msharefs_info { + struct dentry *info_dentry; +}; + +static ssize_t +mshare_info_read(struct file *file, char __user *buf, size_t nbytes, + loff_t *ppos) +{ + char s[80]; + + sprintf(s, "%ld\n", mshare_align); + return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s)); +} + +static const struct file_operations mshare_info_ops = { + .read = mshare_info_read, + .llseek = noop_llseek, +}; + static const struct super_operations mshare_s_ops = { .statfs = simple_statfs, }; +static int +msharefs_create_mshare_info(struct super_block *sb) +{ + struct msharefs_info *info = sb->s_fs_info; + struct dentry *root = sb->s_root; + struct dentry *dentry; + struct inode *inode; + int ret; + + ret = -ENOMEM; + inode = new_inode(sb); + if (!inode) + goto out; + + inode->i_ino = 2; + simple_inode_init_ts(inode); + inode_init_owner(&nop_mnt_idmap, inode, NULL, S_IFREG | 0444); + inode->i_fop = &mshare_info_ops; + + dentry = d_alloc_name(root, "mshare_info"); + if (!dentry) + goto out; + + info->info_dentry = dentry; + d_add(dentry, inode); + + return 0; +out: + iput(inode); + + return ret; +} + static int msharefs_fill_super(struct super_block *sb, struct fs_context *fc) { + struct msharefs_info *info; struct inode *inode; + int ret; sb->s_blocksize = PAGE_SIZE; sb->s_blocksize_bits = PAGE_SHIFT; @@ -37,6 +93,12 @@ msharefs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_op = &mshare_s_ops; sb->s_time_gran = 1; + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) + return -ENOMEM; + + sb->s_fs_info = info; + inode = new_inode(sb); if (!inode) return -ENOMEM; @@ -52,7 +114,9 @@ msharefs_fill_super(struct super_block *sb, struct fs_context *fc) if (!sb->s_root) return -ENOMEM; - return 0; + ret = msharefs_create_mshare_info(sb); + + return ret; } static int @@ -72,10 +136,19 @@ mshare_init_fs_context(struct fs_context *fc) return 0; } +static void +msharefs_kill_super(struct super_block *sb) +{ + struct msharefs_info *info = sb->s_fs_info; + + kfree(info); + kill_litter_super(sb); +} + static struct file_system_type mshare_fs = { .name = "msharefs", .init_fs_context = mshare_init_fs_context, - .kill_sb = kill_litter_super, + .kill_sb = msharefs_kill_super, }; static int __init -- 2.43.5