linux-kernel - [PATCH 4/4] tpm: Provide a function tpm_chip

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Date:   Sat, 16 Jan 2021 02:22:41 +0100
From:   Lino Sanfilippo <LinoSanfilippo@....de>
To:     peterhuewe@....de, jarkko@...nel.org
Cc:     jgg@...pe.ca, stefanb@...ux.vnet.ibm.com,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        LinoSanfilippo@....de, p.rosenberger@...bus.com,
        Lino Sanfilippo <l.sanfilippo@...bus.com>
Subject: [PATCH 4/4] tpm: Provide a function tpm_chip_free() to free tpm chips

From: Lino Sanfilippo <l.sanfilippo@...bus.com>

Provide a function tpm_chip_free() as a counterpart to tpm_chip_alloc().
The function hides the internals of freeing a struct tpm_chip instance
by putting the device references which are part of this structure.

Use the new function at the appropriate places.

Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
---
 drivers/char/tpm/tpm-chip.c       | 16 ++++++++++++++++
 drivers/char/tpm/tpm.h            |  1 +
 drivers/char/tpm/tpm_ftpm_tee.c   |  6 ++----
 drivers/char/tpm/tpm_vtpm_proxy.c |  3 +--
 4 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 596824c..85e987b 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -402,6 +402,22 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 EXPORT_SYMBOL_GPL(tpm_chip_alloc);
 
 /**
+ * tpm_chip_free() - free an instance of struct tpm_chip that has been
+ * allocated with tpm_chip_alloc() before.
+ * @chip: chip to free
+ *
+ * Frees an instance of struct tpm_chip by releasing internal device references.
+ * This function is used to hide the internals needed to free a struct tpm_chip
+ * instance thas has been allocated with tpm_chip_alloc() before.
+ */
+void tpm_chip_free(struct tpm_chip *chip)
+{
+	put_device(&chip->devs);
+	put_device(&chip->dev);
+}
+EXPORT_SYMBOL_GPL(tpm_chip_free);
+
+/**
  * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
  * @pdev: parent device to which the chip is associated
  * @ops: struct tpm_class_ops instance
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 947d1db..e6bb6ae 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -199,6 +199,7 @@ void tpm_put_ops(struct tpm_chip *chip);
 
 struct tpm_chip *tpm_chip_alloc(struct device *dev,
 				const struct tpm_class_ops *ops);
+void tpm_chip_free(struct tpm_chip *chip);
 struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
 				 const struct tpm_class_ops *ops);
 int tpm_chip_register(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c
index 82858c2..47ffaae 100644
--- a/drivers/char/tpm/tpm_ftpm_tee.c
+++ b/drivers/char/tpm/tpm_ftpm_tee.c
@@ -285,8 +285,7 @@ static int ftpm_tee_probe(struct device *dev)
 	return 0;
 
 out_chip:
-	put_device(&pvt_data->chip->dev);
-	put_device(&pvt_data->chip->devs);
+	tpm_chip_free(chip);
 out_chip_alloc:
 	tee_shm_free(pvt_data->shm);
 out_shm_alloc:
@@ -319,8 +318,7 @@ static int ftpm_tee_remove(struct device *dev)
 	tpm_chip_unregister(pvt_data->chip);
 
 	/* frees chip */
-	put_device(&pvt_data->chip->devs);
-	put_device(&pvt_data->chip->dev);
+	tpm_chip_free(pvt_data->chip);
 
 	/* Free the shared memory pool */
 	tee_shm_free(pvt_data->shm);
diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
index 97b60f8..f887bb3 100644
--- a/drivers/char/tpm/tpm_vtpm_proxy.c
+++ b/drivers/char/tpm/tpm_vtpm_proxy.c
@@ -520,8 +520,7 @@ static struct proxy_dev *vtpm_proxy_create_proxy_dev(void)
  */
 static inline void vtpm_proxy_delete_proxy_dev(struct proxy_dev *proxy_dev)
 {
-	put_device(&proxy_dev->chip->devs);
-	put_device(&proxy_dev->chip->dev); /* frees chip */
+	tpm_chip_free(proxy_dev->chip);
 	kfree(proxy_dev);
 }
 
-- 
2.7.4