linux-kernel - [PATCH v3 2/4] soc: qcom: pmic_glink: simplify locking with guard()

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Message-ID: <20241209115613.83675-2-krzysztof.kozlowski@linaro.org>
Date: Mon,  9 Dec 2024 12:56:11 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konradybcio@...nel.org>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Andy Gross <agross@...eaurora.org>,
	linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Subject: [PATCH v3 2/4] soc: qcom: pmic_glink: simplify locking with guard()

Simplify error handling over locks with guard().  In few places this
elimiates error gotos and local variables.  Switch to guard() everywhere
(except when jumps would go over scoped guard) for consistency, even if
it does not bring benefit in such places.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>

---

The part in pmic_glink_rpmsg_probe() depends on previous fix.

Changes in v3:
1. Rebase - bigger changes in pmic_glink_send() comparing to v2.

Changes in v2:
1. Do not use guard() in pmic_glink_probe() because of jump.
---
 drivers/soc/qcom/pmic_glink.c | 51 ++++++++++++-----------------------
 1 file changed, 17 insertions(+), 34 deletions(-)

diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c
index 11e88053cc11..f842ffa3c356 100644
--- a/drivers/soc/qcom/pmic_glink.c
+++ b/drivers/soc/qcom/pmic_glink.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2022, Linaro Ltd
  */
 #include <linux/auxiliary_bus.h>
+#include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -100,15 +101,13 @@ void pmic_glink_client_register(struct pmic_glink_client *client)
 	struct pmic_glink *pg = client->pg;
 	unsigned long flags;
 
-	mutex_lock(&pg->state_lock);
+	guard(mutex)(&pg->state_lock);
 	spin_lock_irqsave(&pg->client_lock, flags);
 
 	list_add(&client->node, &pg->clients);
 	client->pdr_notify(client->priv, pg->client_state);
 
 	spin_unlock_irqrestore(&pg->client_lock, flags);
-	mutex_unlock(&pg->state_lock);
-
 }
 EXPORT_SYMBOL_GPL(pmic_glink_client_register);
 
@@ -119,28 +118,23 @@ int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len)
 	unsigned long start;
 	int ret;
 
-	mutex_lock(&pg->state_lock);
+	guard(mutex)(&pg->state_lock);
 	if (!pg->ept) {
-		ret = -ECONNRESET;
+		return -ECONNRESET;
 	} else {
 		start = jiffies;
 		for (;;) {
 			ret = rpmsg_send(pg->ept, data, len);
 			if (ret != -EAGAIN)
-				break;
+				return ret;
 
-			if (timeout_reached) {
-				ret = -ETIMEDOUT;
-				break;
-			}
+			if (timeout_reached)
+				return -ETIMEDOUT;
 
 			usleep_range(1000, 5000);
 			timeout_reached = time_after(jiffies, start + PMIC_GLINK_SEND_TIMEOUT);
 		}
 	}
-	mutex_unlock(&pg->state_lock);
-
-	return ret;
 }
 EXPORT_SYMBOL_GPL(pmic_glink_send);
 
@@ -227,52 +221,42 @@ static void pmic_glink_pdr_callback(int state, char *svc_path, void *priv)
 {
 	struct pmic_glink *pg = priv;
 
-	mutex_lock(&pg->state_lock);
+	guard(mutex)(&pg->state_lock);
 	pg->pdr_state = state;
 
 	pmic_glink_state_notify_clients(pg);
-	mutex_unlock(&pg->state_lock);
 }
 
 static int pmic_glink_rpmsg_probe(struct rpmsg_device *rpdev)
 {
 	struct pmic_glink *pg;
-	int ret = 0;
 
-	mutex_lock(&__pmic_glink_lock);
+	guard(mutex)(&__pmic_glink_lock);
 	pg = __pmic_glink;
-	if (!pg) {
-		ret = dev_err_probe(&rpdev->dev, -ENODEV, "no pmic_glink device to attach to\n");
-		goto out_unlock;
-	}
+	if (!pg)
+		return dev_err_probe(&rpdev->dev, -ENODEV, "no pmic_glink device to attach to\n");
 
 	dev_set_drvdata(&rpdev->dev, pg);
 
-	mutex_lock(&pg->state_lock);
+	guard(mutex)(&pg->state_lock);
 	pg->ept = rpdev->ept;
 	pmic_glink_state_notify_clients(pg);
-	mutex_unlock(&pg->state_lock);
 
-out_unlock:
-	mutex_unlock(&__pmic_glink_lock);
-	return ret;
+	return 0;
 }
 
 static void pmic_glink_rpmsg_remove(struct rpmsg_device *rpdev)
 {
 	struct pmic_glink *pg;
 
-	mutex_lock(&__pmic_glink_lock);
+	guard(mutex)(&__pmic_glink_lock);
 	pg = __pmic_glink;
 	if (!pg)
-		goto out_unlock;
+		return;
 
-	mutex_lock(&pg->state_lock);
+	guard(mutex)(&pg->state_lock);
 	pg->ept = NULL;
 	pmic_glink_state_notify_clients(pg);
-	mutex_unlock(&pg->state_lock);
-out_unlock:
-	mutex_unlock(&__pmic_glink_lock);
 }
 
 static const struct rpmsg_device_id pmic_glink_rpmsg_id_match[] = {
@@ -379,9 +363,8 @@ static void pmic_glink_remove(struct platform_device *pdev)
 	if (pg->client_mask & BIT(PMIC_GLINK_CLIENT_UCSI))
 		pmic_glink_del_aux_device(pg, &pg->ucsi_aux);
 
-	mutex_lock(&__pmic_glink_lock);
+	guard(mutex)(&__pmic_glink_lock);
 	__pmic_glink = NULL;
-	mutex_unlock(&__pmic_glink_lock);
 }
 
 static const unsigned long pmic_glink_sc8280xp_client_mask = BIT(PMIC_GLINK_CLIENT_BATT) |
-- 
2.43.0