linux-kernel - Applied "regulator: core: have regulator_dev_lookup() return ERR_PTR-encoded errors" to the regulator tree

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Message-Id: <E1cajUN-0001yd-Hc@finisterre>
Date:   Mon, 06 Feb 2017 13:37:51 +0000
From:   Mark Brown <broonie@...nel.org>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:     Mark Brown <broonie@...nel.org>, Mark Brown <broonie@...nel.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        linux-kernel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Applied "regulator: core: have regulator_dev_lookup() return ERR_PTR-encoded errors" to the regulator tree

The patch

   regulator: core: have regulator_dev_lookup() return ERR_PTR-encoded errors

has been applied to the regulator tree at

   git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 163478dae0b6ce2437488e54012705b53ef43f3d Mon Sep 17 00:00:00 2001
From: Dmitry Torokhov <dmitry.torokhov@...il.com>
Date: Sat, 4 Feb 2017 10:19:21 -0800
Subject: [PATCH] regulator: core: have regulator_dev_lookup() return
 ERR_PTR-encoded errors

Instead of returning both regulator_dev structure as return value and
auxiliary error code in 'ret' argument, let's switch to using ERR_PTR
encoded values. This makes it more obvious what is going on at call sites.

Also, let's not unlock the mutex in the middle of a loop, but rather break
out and have single unlock path.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
Signed-off-by: Mark Brown <broonie@...nel.org>
---
 drivers/regulator/core.c | 42 +++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 867756651544..3e246c82939d 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1455,12 +1455,14 @@ static struct regulator_dev *regulator_lookup_by_name(const char *name)
  * lookup could succeed in the future.
  *
  * If successful, returns a struct regulator_dev that corresponds to the name
- * @supply and with the embedded struct device refcount incremented by one,
- * or NULL on failure. The refcount must be dropped by calling put_device().
+ * @supply and with the embedded struct device refcount incremented by one.
+ * The refcount must be dropped by calling put_device().
+ * On failure one of the following ERR-PTR-encoded values is returned:
+ * -ENODEV if lookup fails permanently, -EPROBE_DEFER if lookup could succeed
+ * in the future.
  */
 static struct regulator_dev *regulator_dev_lookup(struct device *dev,
-						  const char *supply,
-						  int *ret)
+						  const char *supply)
 {
 	struct regulator_dev *r;
 	struct device_node *node;
@@ -1476,16 +1478,12 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
 			r = of_find_regulator_by_node(node);
 			if (r)
 				return r;
-			*ret = -EPROBE_DEFER;
-			return NULL;
-		} else {
+
 			/*
-			 * If we couldn't even get the node then it's
-			 * not just that the device didn't register
-			 * yet, there's no node and we'll never
-			 * succeed.
+			 * We have a node, but there is no device.
+			 * assume it has not registered yet.
 			 */
-			*ret = -ENODEV;
+			return ERR_PTR(-EPROBE_DEFER);
 		}
 	}
 
@@ -1506,13 +1504,16 @@ static struct regulator_dev *regulator_dev_lookup(struct device *dev,
 
 		if (strcmp(map->supply, supply) == 0 &&
 		    get_device(&map->regulator->dev)) {
-			mutex_unlock(&regulator_list_mutex);
-			return map->regulator;
+			r = map->regulator;
+			break;
 		}
 	}
 	mutex_unlock(&regulator_list_mutex);
 
-	return NULL;
+	if (r)
+		return r;
+
+	return ERR_PTR(-ENODEV);
 }
 
 static int regulator_resolve_supply(struct regulator_dev *rdev)
@@ -1529,8 +1530,10 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
 	if (rdev->supply)
 		return 0;
 
-	r = regulator_dev_lookup(dev, rdev->supply_name, &ret);
-	if (!r) {
+	r = regulator_dev_lookup(dev, rdev->supply_name);
+	if (IS_ERR(r)) {
+		ret = PTR_ERR(r);
+
 		if (ret == -ENODEV) {
 			/*
 			 * No supply was specified for this regulator and
@@ -1601,10 +1604,11 @@ struct regulator *_regulator_get(struct device *dev, const char *id,
 	if (dev)
 		devname = dev_name(dev);
 
-	rdev = regulator_dev_lookup(dev, id, &ret);
-	if (rdev)
+	rdev = regulator_dev_lookup(dev, id);
+	if (!IS_ERR(rdev))
 		goto found;
 
+	ret = PTR_ERR(rdev);
 	regulator = ERR_PTR(ret);
 
 	/*
-- 
2.11.0