[PATCH v2 3/4] tpm: Hold the kref during tpm_chip_find_get

[Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>]

From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

This was missed during the struct device conversion, we
need to hold a kref on the chip to make sure it isn't freed.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.cm>
Fixes: afb5abc262e9 ("tpm: two-phase chip management functions")
cc: stable@vger.kernel.org
---
 drivers/char/tpm/tpm-chip.c | 2 ++
 drivers/char/tpm/tpm.h      | 1 +
 2 files changed, 3 insertions(+)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 274dd01..84a54a2 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -53,6 +53,8 @@ struct tpm_chip *tpm_chip_find_get(int chip_num)
 			chip = pos;
 			break;
 		}
+
+		get_device(&chip->dev);
 	}
 	rcu_read_unlock();
 	return chip;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 28b477e..f6bc0b3 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -200,6 +200,7 @@ struct tpm_chip {
 static inline void tpm_chip_put(struct tpm_chip *chip)
 {
 	module_put(chip->pdev->driver->owner);
+	put_device(&chip->dev);
 }
 
 static inline int tpm_read_index(int base, int index)
-- 
2.7.0