linux-kernel - [PATCH] Do not disable driver and bus shutdown hook when class shutdown hook is set.

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Message-Id: <20170809213420.2391-1-msuchanek@suse.de>
Date:   Wed,  9 Aug 2017 23:34:20 +0200
From:   Michal Suchanek <msuchanek@...e.de>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        linux-kernel@...r.kernel.org, tpmdd-devel@...ts.sourceforge.net
Cc:     Michal Suchanek <msuchanek@...e.de>
Subject: [PATCH] Do not disable driver and bus shutdown hook when class shutdown hook is set.

Disabling the driver hook by setting class hook is totally sound design
not prone to error as evidenced by the single implementation of the
class hook.

Fixes: d1bd4a792d39 ("tpm: Issue a TPM2_Shutdown for TPM2 devices.")
Fixes: f77af1516584 ("Add "shutdown" to "struct class".")

Signed-off-by: Michal Suchanek <msuchanek@...e.de>
---
 drivers/base/core.c         | 3 ++-
 drivers/char/tpm/tpm-chip.c | 9 +--------
 2 files changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 755451f684bc..2cf752dc1421 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -2668,7 +2668,8 @@ void device_shutdown(void)
 			if (initcall_debug)
 				dev_info(dev, "shutdown\n");
 			dev->class->shutdown(dev);
-		} else if (dev->bus && dev->bus->shutdown) {
+		}
+		if (dev->bus && dev->bus->shutdown) {
 			if (initcall_debug)
 				dev_info(dev, "shutdown\n");
 			dev->bus->shutdown(dev);
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 67ec9d3d04f5..edf8fa553f5f 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -164,14 +164,7 @@ static int tpm_class_shutdown(struct device *dev)
 		chip->ops = NULL;
 		up_write(&chip->ops_sem);
 	}
-	/* Allow bus- and device-specific code to run. Note: since chip->ops
-	 * is NULL, more-specific shutdown code will not be able to issue TPM
-	 * commands.
-	 */
-	if (dev->bus && dev->bus->shutdown)
-		dev->bus->shutdown(dev);
-	else if (dev->driver && dev->driver->shutdown)
-		dev->driver->shutdown(dev);
+
 	return 0;
 }
 
-- 
2.10.2