[PATCH v3 1/4] tpm: Remove tpm_find_get_ops

Jonathan McDowell
2025-10-20T11:43:03Z

From: Jonathan McDowell <noodles@meta.com>

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>
---
v2: No changes.
v3: Move to start of patch series

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();
}
--
2.51.0