1 files changed, 46 insertions, 22 deletions

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 0a62c19937b6..46caadca916a 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -81,42 +81,66 @@ void tpm_put_ops(struct tpm_chip *chip)
 EXPORT_SYMBOL_GPL(tpm_put_ops);
 
 /**
- * tpm_chip_find_get() - find and reserve a TPM chip
+ * tpm_default_chip() - find a TPM chip and get a reference to it
+ */
+struct tpm_chip *tpm_default_chip(void)
+{
+	struct tpm_chip *chip, *res = NULL;
+	int chip_num = 0;
+	int chip_prev;
+
+	mutex_lock(&idr_lock);
+
+	do {
+		chip_prev = chip_num;
+		chip = idr_get_next(&dev_nums_idr, &chip_num);
+		if (chip) {
+			get_device(&chip->dev);
+			res = chip;
+			break;
+		}
+	} while (chip_prev != chip_num);
+
+	mutex_unlock(&idr_lock);
+
+	return res;
+}
+EXPORT_SYMBOL_GPL(tpm_default_chip);
+
+/**
+ * tpm_find_get_ops() - find and reserve a TPM chip
  * @chip:	a &struct tpm_chip instance, %NULL for the default chip
  *
  * Finds a TPM chip and reserves its class device and operations. The chip must
- * be released with tpm_chip_put_ops() after use.
+ * be released with tpm_put_ops() after use.
+ * This function is for internal use only. It supports existing TPM callers
+ * by accepting NULL, but those callers should be converted to pass in a chip
+ * directly.
  *
  * Return:
  * A reserved &struct tpm_chip instance.
  * %NULL if a chip is not found.
  * %NULL if the chip is not available.
  */
-struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip)
+struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip)
 {
-	struct tpm_chip *res = NULL;
-	int chip_num = 0;
-	int chip_prev;
-
-	mutex_lock(&idr_lock);
+	int rc;
 
-	if (!chip) {
-		do {
-			chip_prev = chip_num;
-			chip = idr_get_next(&dev_nums_idr, &chip_num);
-			if (chip && !tpm_try_get_ops(chip)) {
-				res = chip;
-				break;
-			}
-		} while (chip_prev != chip_num);
-	} else {
+	if (chip) {
 		if (!tpm_try_get_ops(chip))
-			res = chip;
+			return chip;
+		return NULL;
 	}
 
-	mutex_unlock(&idr_lock);
-
-	return res;
+	chip = tpm_default_chip();
+	if (!chip)
+		return NULL;
+	rc = tpm_try_get_ops(chip);
+	/* release additional reference we got from tpm_default_chip() */
+	put_device(&chip->dev);
+	if (rc)
+		return NULL;
+	return chip;
 }
 
 /**