power: smb-lib: Fix mutex acquisition deadlock on PD hard reset

Mutex acquisition deadlock can happen while cancelling cc_dettach
work during pd_hard_reset from the function usbin_plugin_hard_reset
_locked on vbus rise which is called in the same lock context that
we try to acquire in the cc_dettach work routine.
Check if cc_dettach work is running during pd_hard_reset and use
trylock instead of mutex_lock to prevent any deadlock if mutext is
already held.

Change-Id: I5530deb9e654d3d12ba1b4bc6876f36127a0d5a5
Signed-off-by: Umang Agrawal <uagrawal@codeaurora.org>

1 files changed, 22 insertions, 2 deletions

diff --git a/drivers/power/supply/qcom/smb-lib.c b/drivers/power/supply/qcom/smb-lib.c
index 81623c65ea8e..1782f23fafa7 100644
--- a/drivers/power/supply/qcom/smb-lib.c
+++ b/drivers/power/supply/qcom/smb-lib.c
@@ -4457,6 +4457,7 @@ static void rdstd_cc2_detach_work(struct work_struct *work)
 {
 	int rc;
 	u8 stat4, stat5;
+	bool lock = false;
 	struct smb_charger *chg = container_of(work, struct smb_charger,
 						rdstd_cc2_detach_work);
 
@@ -4519,9 +4520,28 @@ static void rdstd_cc2_detach_work(struct work_struct *work)
 	rc = smblib_masked_write(chg, TYPE_C_INTRPT_ENB_SOFTWARE_CTRL_REG,
 						EXIT_SNK_BASED_ON_CC_BIT, 0);
 	smblib_reg_block_restore(chg, cc2_detach_settings);
-	mutex_lock(&chg->lock);
+
+	/*
+	 * Mutex acquisition deadlock can happen while cancelling this work
+	 * during pd_hard_reset from the function smblib_cc2_sink_removal_exit
+	 * which is called in the same lock context that we try to acquire in
+	 * this work routine.
+	 * Check if this work is running during pd_hard_reset and use trylock
+	 * instead of mutex_lock to prevent any deadlock if mutext is already
+	 * held.
+	 */
+	if (chg->pd_hard_reset) {
+		if (mutex_trylock(&chg->lock))
+			lock = true;
+	} else {
+		mutex_lock(&chg->lock);
+		lock = true;
+	}
+
 	smblib_usb_typec_change(chg);
-	mutex_unlock(&chg->lock);
+
+	if (lock)
+		mutex_unlock(&chg->lock);
 	return;
 
 rerun: