It has been reported that some TIS based TPMs are giving unexpected
errors when using the O_NONBLOCK path of the TPM device. The problem
is that some TPMs don't like it when you get and then relinquish a
locality (as the tpm_try_get_ops()/tpm_put_ops() pair does) without
sending a command.  This currently happens all the time in the
O_NONBLOCK write path. Fix this by moving the tpm_try_get_ops()
further down the code to after the O_NONBLOCK determination is made.
This is safe because the priv->buffer_mutex still protects the priv
state being modified.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206275
Fixes: d23d1248 ("tpm: fix invalid locking in NONBLOCKING mode")
Reported-by: Mario Limonciello <Mario.Limonciello@dell.com>
Tested-by: Alex Guzman <alex@guzman.io>
Cc: stable@vger.kernel.org
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>