[PATCH] tpm: locking fix

Use schedule_work() to avoid down()-in-timer-handler problem.
Signed-off-by: NKylene Hall <kjhall@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

drivers/char/tpm/tpm.c

@@ -43,6 +43,13 @@ static void user_reader_timeout(unsigned long ptr)
 {
 	struct tpm_chip *chip = (struct tpm_chip *) ptr;
 
+	schedule_work(&chip->work);
+}
+
+static void timeout_work(void * ptr)
+{
+	struct tpm_chip *chip = ptr;
+
 	down(&chip->buffer_mutex);
 	atomic_set(&chip->data_pending, 0);
 	memset(chip->data_buffer, 0, TPM_BUFSIZE);
@@ -527,6 +534,8 @@ int tpm_register_hardware(struct device *dev, struct tpm_vendor_specific *entry)
 	init_MUTEX(&chip->tpm_mutex);
 	INIT_LIST_HEAD(&chip->list);
 
+	INIT_WORK(&chip->work, timeout_work, chip);
+
 	init_timer(&chip->user_read_timer);
 	chip->user_read_timer.function = user_reader_timeout;
 	chip->user_read_timer.data = (unsigned long) chip;

drivers/char/tpm/tpm.h

@@ -77,6 +77,7 @@ struct tpm_chip {
 	struct semaphore buffer_mutex;
 
 	struct timer_list user_read_timer;	/* user needs to claim result */
+	struct work_struct work;
 	struct semaphore tpm_mutex;	/* tpm is processing */
 
 	struct tpm_vendor_specific *vendor;