tpm_tis: fix tis_lock with respect to RCU

cleanup_tis() -> tpm_remove_hardware() -> syncrhonize_rcu() is being
called in an atomic context (tis_lock spinlock held), which is not
allowed. Convert tis_lock to mutex.
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Tested-by: NStefan Berger <stefanb@linux.vnet.ibm.com>
Acked-by: NRajiv Andrade <srajiv@linux.vnet.ibm.com>

drivers/char/tpm/tpm_tis.c

@@ -76,7 +76,7 @@ enum tis_defaults {
 #define	TPM_RID(l)			(0x0F04 | ((l) << 12))
 
 static LIST_HEAD(tis_chips);
-static DEFINE_SPINLOCK(tis_lock);
+static DEFINE_MUTEX(tis_lock);
 
 #if defined(CONFIG_PNP) && defined(CONFIG_ACPI)
 static int is_itpm(struct pnp_dev *dev)
@@ -689,9 +689,9 @@ static int tpm_tis_init(struct device *dev, resource_size_t start,
 	}
 
 	INIT_LIST_HEAD(&chip->vendor.list);
-	spin_lock(&tis_lock);
+	mutex_lock(&tis_lock);
 	list_add(&chip->vendor.list, &tis_chips);
-	spin_unlock(&tis_lock);
+	mutex_unlock(&tis_lock);
 
 
 	return 0;
@@ -855,7 +855,7 @@ static void __exit cleanup_tis(void)
 {
 	struct tpm_vendor_specific *i, *j;
 	struct tpm_chip *chip;
-	spin_lock(&tis_lock);
+	mutex_lock(&tis_lock);
 	list_for_each_entry_safe(i, j, &tis_chips, list) {
 		chip = to_tpm_chip(i);
 		tpm_remove_hardware(chip->dev);
@@ -871,7 +871,7 @@ static void __exit cleanup_tis(void)
 		iounmap(i->iobase);
 		list_del(&i->list);
 	}
-	spin_unlock(&tis_lock);
+	mutex_unlock(&tis_lock);
 #ifdef CONFIG_PNP
 	if (!force) {
 		pnp_unregister_driver(&tis_pnp_driver);