[PATCH 0/2] dmi-sysfs module unload fixes

[PATCH 0/2] dmi-sysfs module unload fixes

[Bjorn Helgaas]

These fix a warning on dmi-sysfs module unload and an error when
reloading immediately after unload with DEBUG_KOBJECT_RELEASE.

---

Bjorn Helgaas (2):
      firmware: dmi-sysfs: Don't remove dmi-sysfs "raw" file explicitly
      firmware: dmi-sysfs: Remove "dmi" directory on module exit


 drivers/firmware/dmi-sysfs.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

[PATCH 1/2] firmware: dmi-sysfs: Don't remove dmi-sysfs "raw" file explicitly

[Bjorn Helgaas]

Removing the dmi-sysfs module causes the following warning:

  # modprobe -r dmi_sysfs
  WARNING: CPU: 11 PID: 6785 at fs/sysfs/inode.c:325 sysfs_hash_and_remove+0xa9/0xb0()
  sysfs: can not remove 'raw', no directory

This is because putting the entry kobject, e.g., for
"/sys/firmware/dmi/entries/19-0", removes the directory and all its
contents.  By the time dmi_sysfs_entry_release() runs, the "raw" file
inside ".../19-0/" has already been removed.

Therefore, we don't need to remove the "raw" bin file at all in
dmi_sysfs_entry_release().

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/firmware/dmi-sysfs.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c
index eb26d62e5188..66200ed5e6a1 100644
--- a/drivers/firmware/dmi-sysfs.c
+++ b/drivers/firmware/dmi-sysfs.c
@@ -553,7 +553,7 @@ static const struct bin_attribute dmi_entry_raw_attr = {
 static void dmi_sysfs_entry_release(struct kobject *kobj)
 {
 	struct dmi_sysfs_entry *entry = to_entry(kobj);
-	sysfs_remove_bin_file(&entry->kobj, &dmi_entry_raw_attr);
+
 	spin_lock(&entry_list_lock);
 	list_del(&entry->list);
 	spin_unlock(&entry_list_lock);

[PATCH 2/2] firmware: dmi-sysfs: Remove "dmi" directory on module exit

[Bjorn Helgaas]

With CONFIG_DEBUG_KOBJECT_RELEASE=y, removing and immediately reloading the
dmi-sysfs module causes the following warning:

  sysfs: cannot create duplicate filename '/firmware/dmi'
  kobject_add_internal failed for dmi with -EEXIST, don't try to register things with the same name in the same directory.

The "dmi" directory stays in sysfs until the dmi_kobj is released, and
DEBUG_KOBJECT_RELEASE delays that.

I don't think we can hit this problem in normal usage because dmi_kobj is
static and nothing outside dmi-sysfs can get a reference to it, so the
only way to delay the "dmi" release is with DEBUG_KOBJECT_RELEASE.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
 drivers/firmware/dmi-sysfs.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/firmware/dmi-sysfs.c b/drivers/firmware/dmi-sysfs.c
index 66200ed5e6a1..e0f1cb3d3598 100644
--- a/drivers/firmware/dmi-sysfs.c
+++ b/drivers/firmware/dmi-sysfs.c
@@ -685,6 +685,7 @@ static void __exit dmi_sysfs_exit(void)
 	pr_debug("dmi-sysfs: unloading.\n");
 	cleanup_entry_list();
 	kset_unregister(dmi_kset);
+	kobject_del(dmi_kobj);
 	kobject_put(dmi_kobj);
 }