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brauner@kernel.org, bsegall@google.com, corbet@lwn.net, dave.hansen@linux.intel.com, david@redhat.com, dietmar.eggemann@arm.com, ebiederm@xmission.com, hpa@zytor.com, jakub.wartak@mailbox.org, jannh@google.com, juri.lelli@redhat.com, khalid@kernel.org, liam.howlett@oracle.com, linyongting@bytedance.com, lorenzo.stoakes@oracle.com, luto@kernel.org, markhemm@googlemail.com, maz@kernel.org, mhiramat@kernel.org, mgorman@suse.de, mhocko@suse.com, mingo@redhat.com, muchun.song@linux.dev, neilb@suse.de, osalvador@suse.de, pcc@google.com, peterz@infradead.org, pfalcato@suse.de, rostedt@goodmis.org, rppt@kernel.org, shakeel.butt@linux.dev, surenb@google.com, tglx@linutronix.de, vasily.averin@linux.dev, vbabka@suse.cz, vincent.guittot@linaro.org, viro@zeniv.linux.org.uk, vschneid@redhat.com, willy@infradead.org, x86@kernel.org, xhao@linux.alibaba.com, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Subject: [PATCH v3 02/22] mm/mshare: pre-populate msharefs 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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 -- 2.47.1