[PATCH 5.4 50/61] slimbus: messaging: check for valid transaction id

Sasha Levin
2021-08-24T17:18:07Z

From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

[ Upstream commit a263c1ff6abe0e66712f40d595bbddc7a35907f8 ]

In some usecases transaction ids are dynamically allocated inside
the controller driver after sending the messages which have generic
acknowledge responses. So check for this before refcounting pm_runtime.

Without this we would end up imbalancing runtime pm count by
doing pm_runtime_put() in both slim_do_transfer() and slim_msg_response()
for a single pm_runtime_get() in slim_do_transfer()

Fixes: d3062a210930 ("slimbus: messaging: add slim_alloc/free_txn_tid()")
Cc: <stable@vger.kernel.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20210809082428.11236-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/slimbus/messaging.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/slimbus/messaging.c b/drivers/slimbus/messaging.c
index 3b77713f1e3f..ddf0371ad52b 100644
--- a/drivers/slimbus/messaging.c
+++ b/drivers/slimbus/messaging.c
@@ -131,7 +131,8 @@ int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
goto slim_xfer_err;
}
}
-
+ /* Initialize tid to invalid value */
+ txn->tid = 0;
need_tid = slim_tid_txn(txn->mt, txn->mc);

if (need_tid) {
@@ -163,7 +164,7 @@ int slim_do_transfer(struct slim_controller *ctrl, struct slim_msg_txn *txn)
txn->mt, txn->mc, txn->la, ret);

slim_xfer_err:
- if (!clk_pause_msg && (!need_tid || ret == -ETIMEDOUT)) {
+ if (!clk_pause_msg && (txn->tid == 0 || ret == -ETIMEDOUT)) {
/*
* remove runtime-pm vote if this was TX only, or
* if there was error during this transaction
--
2.30.2