linux-kernel - [PATCH AUTOSEL 6.5 51/52] Revert "pinctrl: avoid unsafe code pattern in find

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Date:   Sun, 29 Oct 2023 18:53:38 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Sasha Levin <sashal@...nel.org>, linux-gpio@...r.kernel.org
Subject: [PATCH AUTOSEL 6.5 51/52] Revert "pinctrl: avoid unsafe code pattern in find_pinctrl()"

From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

[ Upstream commit 62140a1e4dec4594d5d1e1d353747bf2ef434e8b ]

The commit breaks MMC enumeration on the Intel Merrifield
plaform.

Before:
[   36.439057] mmc0: SDHCI controller on PCI [0000:00:01.0] using ADMA
[   36.450924] mmc2: SDHCI controller on PCI [0000:00:01.3] using ADMA
[   36.459355] mmc1: SDHCI controller on PCI [0000:00:01.2] using ADMA
[   36.706399] mmc0: new DDR MMC card at address 0001
[   37.058972] mmc2: new ultra high speed DDR50 SDIO card at address 0001
[   37.278977] mmcblk0: mmc0:0001 H4G1d 3.64 GiB
[   37.297300]  mmcblk0: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10

After:
[   36.436704] mmc2: SDHCI controller on PCI [0000:00:01.3] using ADMA
[   36.436720] mmc1: SDHCI controller on PCI [0000:00:01.0] using ADMA
[   36.463685] mmc0: SDHCI controller on PCI [0000:00:01.2] using ADMA
[   36.720627] mmc1: new DDR MMC card at address 0001
[   37.068181] mmc2: new ultra high speed DDR50 SDIO card at address 0001
[   37.279998] mmcblk1: mmc1:0001 H4G1d 3.64 GiB
[   37.302670]  mmcblk1: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10

This reverts commit c153a4edff6ab01370fcac8e46f9c89cca1060c2.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Link: https://lore.kernel.org/r/20231017141806.535191-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/pinctrl/core.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index b84781cfc2596..401886c813449 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -1012,20 +1012,17 @@ static int add_setting(struct pinctrl *p, struct pinctrl_dev *pctldev,
 
 static struct pinctrl *find_pinctrl(struct device *dev)
 {
-	struct pinctrl *entry, *p = NULL;
+	struct pinctrl *p;
 
 	mutex_lock(&pinctrl_list_mutex);
-
-	list_for_each_entry(entry, &pinctrl_list, node) {
-		if (entry->dev == dev) {
-			p = entry;
-			kref_get(&p->users);
-			break;
+	list_for_each_entry(p, &pinctrl_list, node)
+		if (p->dev == dev) {
+			mutex_unlock(&pinctrl_list_mutex);
+			return p;
 		}
-	}
 
 	mutex_unlock(&pinctrl_list_mutex);
-	return p;
+	return NULL;
 }
 
 static void pinctrl_free(struct pinctrl *p, bool inlist);
@@ -1133,6 +1130,7 @@ struct pinctrl *pinctrl_get(struct device *dev)
 	p = find_pinctrl(dev);
 	if (p) {
 		dev_dbg(dev, "obtain a copy of previously claimed pinctrl\n");
+		kref_get(&p->users);
 		return p;
 	}
 
-- 
2.42.0