tpm, tpm_tis: do not check for the active locality in interrupt handler

JIRA: https://issues.redhat.com/browse/RHEL-72765

Upstream Status: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

commit 35f6212
Author: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Date:   Thu Nov 24 14:55:32 2022 +0100

    tpm, tpm_tis: do not check for the active locality in interrupt handler

    After driver initialization tpm_tis_data->locality may only be modified in
    case of a LOCALITY CHANGE interrupt. In this case the interrupt handler
    iterates over all localities only to assign the active one to
    tpm_tis_data->locality.

    However this information is never used any more, so the assignment is not
    needed.
    Furthermore without the assignment tpm_tis_data->locality cannot change any
    more at driver runtime, and thus no protection against concurrent
    modification is required when the variable is read at other places.

    So remove this iteration entirely.

    Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
    Tested-by: Jarkko Sakkinen <jarkko@kernel.org>
    Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
    Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

Signed-off-by: Štěpán Horáček <shoracek@redhat.com>

Author: shoracek

drivers/char/tpm/tpm_tis_core.c

@@ -714,7 +714,7 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
 	struct tpm_chip *chip = dev_id;
 	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
 	u32 interrupt;
-	int i, rc;
+	int rc;
 
 	rc = tpm_tis_read32(priv, TPM_INT_STATUS(priv->locality), &interrupt);
 	if (rc < 0)
@@ -726,10 +726,7 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
 	set_bit(TPM_TIS_IRQ_TESTED, &priv->flags);
 	if (interrupt & TPM_INTF_DATA_AVAIL_INT)
 		wake_up_interruptible(&priv->read_queue);
-	if (interrupt & TPM_INTF_LOCALITY_CHANGE_INT)
-		for (i = 0; i < 5; i++)
-			if (check_locality(chip, i))
-				break;
+
 	if (interrupt &
 	    (TPM_INTF_LOCALITY_CHANGE_INT | TPM_INTF_STS_VALID_INT |
 	     TPM_INTF_CMD_READY_INT))