[PATCH] Correct misc_register return code handling in several drivers

Clean up several code points in which the return code from misc_register is
not handled properly.

Several modules failed to deregister various hooks when misc_register fails,
and this patch cleans them up.  Also there are a few modules that legitimately
don't care about the failure status of misc register.  These drivers however
unilaterally call misc_deregister on module unload.

Since misc_register doesn't initialize the list_head in the init_routine if it
fails, the deregister operation is at risk for oopsing when list_del is
called.  The initial solution was to manually init the list in the miscdev
structure in each of those modules, but the consensus in this thread was to
consolodate and do that universally inside misc_register.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Kylene Jo Hall <kjhall@us.ibm.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: Olaf Hering <olh@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 774fa861169a..33e1f66e39cb 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -1155,6 +1155,7 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
 
         if (sysfs_create_group(&dev->kobj, chip->vendor.attr_group)) {
                 list_del(&chip->list);
+                misc_deregister(&chip->vendor.miscdev);
                 put_device(dev);
                 clear_bit(chip->dev_num, dev_mask);
                 kfree(chip);