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* [PATCH] tpm: Remove tpm_find_get_ops
@ 2025-11-27 17:02 Jonathan McDowell
  2025-11-27 21:54 ` Jarkko Sakkinen
  0 siblings, 1 reply; 2+ messages in thread
From: Jonathan McDowell @ 2025-11-27 17:02 UTC (permalink / raw)
  To: Peter Huewe, Jarkko Sakkinen, Jason Gunthorpe
  Cc: linux-integrity, linux-kernel

tpm_find_get_ops() looks for the first valid TPM if the caller passes in
NULL. All internal users have been converted to either associate
themselves with a TPM directly, or call tpm_default_chip() as part of
their setup. Remove the no longer necessary tpm_find_get_ops().

Signed-off-by: Jonathan McDowell <noodles@meta.com>
---
(Separating this out from the exclusive access series, because I think 
this bit is uncontroversial and is a legit cleanup.)

 drivers/char/tpm/tpm-chip.c      | 36 --------------------------------
 drivers/char/tpm/tpm-interface.c | 20 ++++++++++++++----
 drivers/char/tpm/tpm.h           |  1 -
 drivers/char/tpm/tpm_tis_core.c  |  3 +--
 4 files changed, 17 insertions(+), 43 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index e25daf2396d3..30d00219f9f3 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -230,42 +230,6 @@ struct tpm_chip *tpm_default_chip(void)
 }
 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_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_find_get_ops(struct tpm_chip *chip)
-{
-	int rc;
-
-	if (chip) {
-		if (!tpm_try_get_ops(chip))
-			return chip;
-		return NULL;
-	}
-
-	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;
-}
-
 /**
  * tpm_dev_release() - free chip memory and the device number
  * @dev: the character device for the TPM chip
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index c9f173001d0e..f745a098908b 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -313,10 +313,13 @@ int tpm_is_tpm2(struct tpm_chip *chip)
 {
 	int rc;
 
-	chip = tpm_find_get_ops(chip);
 	if (!chip)
 		return -ENODEV;
 
+	rc = tpm_try_get_ops(chip);
+	if (rc)
+		return rc;
+
 	rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
 
 	tpm_put_ops(chip);
@@ -338,10 +341,13 @@ int tpm_pcr_read(struct tpm_chip *chip, u32 pcr_idx,
 {
 	int rc;
 
-	chip = tpm_find_get_ops(chip);
 	if (!chip)
 		return -ENODEV;
 
+	rc = tpm_try_get_ops(chip);
+	if (rc)
+		return rc;
+
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		rc = tpm2_pcr_read(chip, pcr_idx, digest, NULL);
 	else
@@ -369,10 +375,13 @@ int tpm_pcr_extend(struct tpm_chip *chip, u32 pcr_idx,
 	int rc;
 	int i;
 
-	chip = tpm_find_get_ops(chip);
 	if (!chip)
 		return -ENODEV;
 
+	rc = tpm_try_get_ops(chip);
+	if (rc)
+		return rc;
+
 	for (i = 0; i < chip->nr_allocated_banks; i++) {
 		if (digests[i].alg_id != chip->allocated_banks[i].alg_id) {
 			rc = -EINVAL;
@@ -492,10 +501,13 @@ int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 	if (!out || max > TPM_MAX_RNG_DATA)
 		return -EINVAL;
 
-	chip = tpm_find_get_ops(chip);
 	if (!chip)
 		return -ENODEV;
 
+	rc = tpm_try_get_ops(chip);
+	if (rc)
+		return rc;
+
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		rc = tpm2_get_random(chip, out, max);
 	else
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 2726bd38e5ac..02c07fef41ba 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -267,7 +267,6 @@ static inline void tpm_msleep(unsigned int delay_msec)
 int tpm_chip_bootstrap(struct tpm_chip *chip);
 int tpm_chip_start(struct tpm_chip *chip);
 void tpm_chip_stop(struct tpm_chip *chip);
-struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);
 
 struct tpm_chip *tpm_chip_alloc(struct device *dev,
 				const struct tpm_class_ops *ops);
diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index 8954a8660ffc..e2a1769081b1 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -265,8 +265,7 @@ static u8 tpm_tis_status(struct tpm_chip *chip)
 
 			/*
 			 * Dump stack for forensics, as invalid TPM_STS.x could be
-			 * potentially triggered by impaired tpm_try_get_ops() or
-			 * tpm_find_get_ops().
+			 * potentially triggered by impaired tpm_try_get_ops().
 			 */
 			dump_stack();
 		}
-- 
2.52.0


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2025-11-27 17:02 [PATCH] tpm: Remove tpm_find_get_ops Jonathan McDowell
2025-11-27 21:54 ` Jarkko Sakkinen

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