linux-kernel - [PATCH v2] tpm: Remove a deprecated comments about implicit sysfs locking

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Message-Id: <20190708145639.23279-1-jarkko.sakkinen@linux.intel.com>
Date:   Mon,  8 Jul 2019 17:56:39 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     linux-integrity@...r.kernel.org
Cc:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Peter Huewe <peterhuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v2] tpm: Remove a deprecated comments about implicit sysfs locking

Remove all comments about implicit locking tpm-sysfs.c as the file was
updated in Linux v5.1 to use explicit locking.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
---
v2: Forgot tpm-sysfs.c changes to my staging area :-/
 drivers/char/tpm/tpm-chip.c  | 7 ++-----
 drivers/char/tpm/tpm-sysfs.c | 7 -------
 2 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index bf868260f435..9311f88afbb4 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -287,12 +287,9 @@ static void tpm_devs_release(struct device *dev)
  * @dev: device to which the chip is associated.
  *
  * Issues a TPM2_Shutdown command prior to loss of power, as required by the
- * TPM 2.0 spec.
- * Then, calls bus- and device- specific shutdown code.
+ * TPM 2.0 spec. Then, calls bus- and device- specific shutdown code.
  *
- * XXX: This codepath relies on the fact that sysfs is not enabled for
- * TPM2: sysfs uses an implicit lock on chip->ops, so this could race if TPM2
- * has sysfs support enabled before TPM sysfs's implicit locking is fixed.
+ * Return: always 0 (i.e. success)
  */
 static int tpm_class_shutdown(struct device *dev)
 {
diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index d9caedda075b..edfa89160010 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -329,16 +329,9 @@ static const struct attribute_group tpm_dev_group = {
 
 void tpm_sysfs_add_device(struct tpm_chip *chip)
 {
-	/* XXX: If you wish to remove this restriction, you must first update
-	 * tpm_sysfs to explicitly lock chip->ops.
-	 */
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		return;
 
-	/* The sysfs routines rely on an implicit tpm_try_get_ops, device_del
-	 * is called before ops is null'd and the sysfs core synchronizes this
-	 * removal so that no callbacks are running or can run again
-	 */
 	WARN_ON(chip->groups_cnt != 0);
 	chip->groups[chip->groups_cnt++] = &tpm_dev_group;
 }
-- 
2.20.1