On 6/30/22 15:37, Darrick J. Wong wrote:
On Wed, Jun 29, 2022 at 04:53:53PM -0600, Khalid Aziz wrote:Users of mshare feature to share page tables need to know the size and alignment requirement for shared regions. Pre-populate msharefs with a file, mshare_info, that provides this information. Signed-off-by: Khalid Aziz <khalid.aziz@xxxxxxxxxx> --- mm/mshare.c | 62 +++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 48 insertions(+), 14 deletions(-) diff --git a/mm/mshare.c b/mm/mshare.c index c8fab3869bab..3e448e11c742 100644 --- a/mm/mshare.c +++ b/mm/mshare.c @@ -25,8 +25,8 @@ static struct super_block *msharefs_sb;static const struct file_operations msharefs_file_operations = {- .open = simple_open, - .llseek = no_llseek, + .open = simple_open, + .llseek = no_llseek,I feel like there's a lot of churn between the previous patch and this one that could have been in the previous patch.
I will look at what changes can be consolidated between two patches, including this change. Thanks for catching this.
};static int@@ -42,23 +42,52 @@ msharefs_d_hash(const struct dentry *dentry, struct qstr *qstr) return 0; }+static void+mshare_evict_inode(struct inode *inode) +{ + clear_inode(inode); +} + static const struct dentry_operations msharefs_d_ops = { .d_hash = msharefs_d_hash, };+static ssize_t+mshare_info_read(struct file *file, char __user *buf, size_t nbytes, + loff_t *ppos) +{ + char s[80]; + + sprintf(s, "%ld", PGDIR_SIZE);SO what is this "mshare_info" file supposed to reveal? Hugepage size? I wonder why this isn't exported in struct mshare_info?
This file gives the alignment and size requirement for mshare regions which is the same for every mshare region. struct mshare_info is a per-mshare region structure that provides starting address and size for just that region.
-- Khalid
+ 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, + .evict_inode = mshare_evict_inode, +}; + static int msharefs_fill_super(struct super_block *sb, struct fs_context *fc) { - static const struct tree_descr empty_descr = {""}; + static const struct tree_descr mshare_files[] = { + [2] = { "mshare_info", &mshare_info_ops, 0444}, + {""}, + }; int err;- sb->s_d_op = &msharefs_d_ops;- err = simple_fill_super(sb, MSHARE_MAGIC, &empty_descr); - if (err) - return err; - - msharefs_sb = sb; - return 0; + err = simple_fill_super(sb, MSHARE_MAGIC, mshare_files); + if (!err) { + msharefs_sb = sb; + sb->s_d_op = &msharefs_d_ops; + sb->s_op = &mshare_s_ops; + } + return err; }static int@@ -84,20 +113,25 @@ static struct file_system_type mshare_fs = { .kill_sb = kill_litter_super, };-static int+static int __init mshare_init(void) { int ret = 0;ret = sysfs_create_mount_point(fs_kobj, "mshare");if (ret) - return ret; + goto out;ret = register_filesystem(&mshare_fs);- if (ret) + if (ret) { sysfs_remove_mount_point(fs_kobj, "mshare"); + goto out; + } + + return 0;+out:return ret; }-fs_initcall(mshare_init);+core_initcall(mshare_init); -- 2.32.0
