tpm: add module_put wrapper

For readability, define a tpm_chip_put() wrapper to call module_put().
Replace existing module_put() calls with the wrapper.

(Change based on trusted/encrypted patchset review by David Howells.)

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Signed-off-by: David Safford <safford@watson.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>

drivers/char/tpm/tpm.c

@@ -736,7 +736,7 @@ int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
 	if (chip == NULL)
 		return -ENODEV;
 	rc = __tpm_pcr_read(chip, pcr_idx, res_buf);
-	module_put(chip->dev->driver->owner);
+	tpm_chip_put(chip);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(tpm_pcr_read);
@@ -775,7 +775,7 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
 	rc = transmit_cmd(chip, &cmd, EXTEND_PCR_RESULT_SIZE,
 			  "attempting extend a PCR value");
 
-	module_put(chip->dev->driver->owner);
+	tpm_chip_put(chip);
 	return rc;
 }
 EXPORT_SYMBOL_GPL(tpm_pcr_extend);

drivers/char/tpm/tpm.h

@@ -113,6 +113,11 @@ struct tpm_chip {
 
 #define to_tpm_chip(n) container_of(n, struct tpm_chip, vendor)
 
+static inline void tpm_chip_put(struct tpm_chip *chip)
+{
+	module_put(chip->dev->driver->owner);
+}
+
 static inline int tpm_read_index(int base, int index)
 {
 	outb(index, base);