ima: Get rid of ima_used_chip and use ima_tpm_chip != NULL instead

Get rid of ima_used_chip and use ima_tpm_chip variable instead for
determining whether to use the TPM chip.
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

security/integrity/ima/ima.h

@@ -53,7 +53,6 @@ enum tpm_pcrs { TPM_PCR0 = 0, TPM_PCR8 = 8 };
 extern int ima_policy_flag;
 
 /* set during initialization */
-extern int ima_used_chip;
 extern int ima_hash_algo;
 extern int ima_appraise;
 extern struct tpm_chip *ima_tpm_chip;

security/integrity/ima/ima_crypto.c

@@ -631,7 +631,7 @@ int ima_calc_buffer_hash(const void *buf, loff_t len,
 
 static void __init ima_pcrread(int idx, u8 *pcr)
 {
-	if (!ima_used_chip)
+	if (!ima_tpm_chip)
 		return;
 
 	if (tpm_pcr_read(ima_tpm_chip, idx, pcr) != 0)

security/integrity/ima/ima_init.c

@@ -26,7 +26,6 @@
 
 /* name for boot aggregate entry */
 static const char *boot_aggregate_name = "boot_aggregate";
-int ima_used_chip;
 struct tpm_chip *ima_tpm_chip;
 
 /* Add the boot aggregate to the IMA measurement list and extend
@@ -65,7 +64,7 @@ static int __init ima_add_boot_aggregate(void)
 	iint->ima_hash->algo = HASH_ALGO_SHA1;
 	iint->ima_hash->length = SHA1_DIGEST_SIZE;
 
-	if (ima_used_chip) {
+	if (ima_tpm_chip) {
 		result = ima_calc_boot_aggregate(&hash.hdr);
 		if (result < 0) {
 			audit_cause = "hashing_error";
@@ -110,9 +109,7 @@ int __init ima_init(void)
 	int rc;
 
 	ima_tpm_chip = tpm_default_chip();
-
-	ima_used_chip = ima_tpm_chip != NULL;
-	if (!ima_used_chip)
+	if (!ima_tpm_chip)
 		pr_info("No TPM chip found, activating TPM-bypass!\n");
 
 	rc = integrity_init_keyring(INTEGRITY_KEYRING_IMA);

security/integrity/ima/ima_queue.c

@@ -142,7 +142,7 @@ static int ima_pcr_extend(const u8 *hash, int pcr)
 {
 	int result = 0;
 
-	if (!ima_used_chip)
+	if (!ima_tpm_chip)
 		return result;
 
 	result = tpm_pcr_extend(ima_tpm_chip, pcr, hash);