[PATCH v4 24/54] convert ibmasmfs

Al Viro
2025-11-18T05:16:10Z

static contents for each "service processor", whatever the fuck it is.
Congruent subdirectories of root, created at mount time, taken out
by kill_litter_super(). All dentries created with d_alloc_name() and are
left pinned. The odd part is that the list of service providers is
assumed to be unchanging - no locking, nothing to handle removals or
extra elements added later on.

... and it's a PCI device. If you ever tell it to remove an instance,
you are fucked - it doesn't bother with removing its directory from filesystem,
it has a strange check that presumably wanted to be a check for removed
devices, but it had never been fleshed out.

Anyway, d_add() -> d_make_persistent()+dput() in ibmasmfs_create_dir() and
ibmasmfs_create_file(), and make the latter return int - no need to even
borrow that dentry, callers completely ignore it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
drivers/misc/ibmasm/ibmasmfs.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/drivers/misc/ibmasm/ibmasmfs.c b/drivers/misc/ibmasm/ibmasmfs.c
index b26c930e3edb..a6cde74efb68 100644
--- a/drivers/misc/ibmasm/ibmasmfs.c
+++ b/drivers/misc/ibmasm/ibmasmfs.c
@@ -103,7 +103,7 @@ static struct file_system_type ibmasmfs_type = {
.owner = THIS_MODULE,
.name = "ibmasmfs",
.init_fs_context = ibmasmfs_init_fs_context,
- .kill_sb = kill_litter_super,
+ .kill_sb = kill_anon_super,
};
MODULE_ALIAS_FS("ibmasmfs");

@@ -144,7 +144,7 @@ static struct inode *ibmasmfs_make_inode(struct super_block *sb, int mode)
return ret;
}

-static struct dentry *ibmasmfs_create_file(struct dentry *parent,
+static int ibmasmfs_create_file(struct dentry *parent,
const char *name,
const struct file_operations *fops,
void *data,
@@ -155,19 +155,20 @@ static struct dentry *ibmasmfs_create_file(struct dentry *parent,

dentry = d_alloc_name(parent, name);
if (!dentry)
- return NULL;
+ return -ENOMEM;

inode = ibmasmfs_make_inode(parent->d_sb, S_IFREG | mode);
if (!inode) {
dput(dentry);
- return NULL;
+ return -ENOMEM;
}

inode->i_fop = fops;
inode->i_private = data;

- d_add(dentry, inode);
- return dentry;
+ d_make_persistent(dentry, inode);
+ dput(dentry);
+ return 0;
}

static struct dentry *ibmasmfs_create_dir(struct dentry *parent,
@@ -189,8 +190,9 @@ static struct dentry *ibmasmfs_create_dir(struct dentry *parent,
inode->i_op = &simple_dir_inode_operations;
inode->i_fop = ibmasmfs_dir_ops;

- d_add(dentry, inode);
- return dentry;
+ d_make_persistent(dentry, inode);
+ dput(dentry);
+ return dentry; // borrowed
}

int ibmasmfs_register(void)
--
2.47.3