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Subject[PATCH] tpm-dev: Require response to be read only if there actually is a response
Date
If the tpm_transmit call in tpm_common_write fails for any reason, there is
no response that could be read. Therefore, do not require the application
to issue a read call before sending further commands. This restores the
behavior from before support for partial reads was introduced.

Signed-off-by: Alexander Steffen <Alexander.Steffen@infineon.com>
---
Feel free to merge this into Tadeusz' original commit.

drivers/char/tpm/tpm-dev-common.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 344739223451..5eecad233ea1 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -140,7 +140,8 @@ ssize_t tpm_common_write(struct file *file, const char __user *buf,
* tpm_read or a user_read_timer timeout. This also prevents split
* buffered writes from blocking here.
*/
- if (!priv->response_read || priv->command_enqueued) {
+ if ((!priv->response_read && priv->response_length) ||
+ priv->command_enqueued) {
ret = -EBUSY;
goto out;
}
--
2.17.1
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