[PATCH] introduce strerrorp

[Sascha Hauer]

putting an error pointer into strerror can be a bit confusing since
strerror takes a positive error code but PTR_ERR returns a negative
number, so we have to do strerror(-PTR_ERR(errp)). Some places got
this wrong already, so introduce a strerrorp function which directly
takes an error pointer.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 common/blspec.c                    | 2 +-
 drivers/usb/imx/imx-usb-phy.c      | 2 +-
 drivers/video/imx-ipu-v3/imx-ldb.c | 8 ++++----
 fs/ubifs/ubifs.c                   | 2 +-
 include/errno.h                    | 6 ++++++
 5 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/common/blspec.c b/common/blspec.c
index ab18602..d5ddb4f 100644
--- a/common/blspec.c
+++ b/common/blspec.c
@@ -646,7 +646,7 @@ static int blspec_append_root(struct blspec_entry *entry)
 	rootarg = path_get_linux_rootarg(entry->rootpath);
 	if (IS_ERR(rootarg)) {
 		pr_err("Getting root argument for %s failed with: %s\n",
-				entry->rootpath, strerror(-PTR_ERR(rootarg)));
+				entry->rootpath, strerrorp(rootarg));
 		return PTR_ERR(rootarg);
 	}
 
diff --git a/drivers/usb/imx/imx-usb-phy.c b/drivers/usb/imx/imx-usb-phy.c
index a573c7f..837c1b5 100644
--- a/drivers/usb/imx/imx-usb-phy.c
+++ b/drivers/usb/imx/imx-usb-phy.c
@@ -78,7 +78,7 @@ static int imx_usbphy_probe(struct device_d *dev)
 
 	imxphy->clk = clk_get(dev, NULL);
 	if (IS_ERR(imxphy->clk)) {
-		dev_err(dev, "could not get clk: %s\n", strerror(-PTR_ERR(imxphy->clk)));
+		dev_err(dev, "could not get clk: %s\n", strerrorp(imxphy->clk));
 		goto err_clk;
 	}
 
diff --git a/drivers/video/imx-ipu-v3/imx-ldb.c b/drivers/video/imx-ipu-v3/imx-ldb.c
index db5f8b6..9eac524 100644
--- a/drivers/video/imx-ipu-v3/imx-ldb.c
+++ b/drivers/video/imx-ipu-v3/imx-ldb.c
@@ -176,7 +176,7 @@ static int imx6q_ldb_prepare(struct imx_ldb_channel *imx_ldb_ch, int di)
 	diclk = clk_lookup(clkname);
 	free(clkname);
 	if (IS_ERR(diclk)) {
-		dev_err(ldb->dev, "failed to get di clk: %s\n", strerror(PTR_ERR(diclk)));
+		dev_err(ldb->dev, "failed to get di clk: %s\n", strerrorp(diclk));
 		return PTR_ERR(diclk);
 	}
 
@@ -184,7 +184,7 @@ static int imx6q_ldb_prepare(struct imx_ldb_channel *imx_ldb_ch, int di)
 	ldbclk = clk_lookup(clkname);
 	free(clkname);
 	if (IS_ERR(ldbclk)) {
-		dev_err(ldb->dev, "failed to get ldb clk: %s\n", strerror(PTR_ERR(ldbclk)));
+		dev_err(ldb->dev, "failed to get ldb clk: %s\n", strerrorp(ldbclk));
 		return PTR_ERR(ldbclk);
 	}
 
@@ -216,7 +216,7 @@ static int imx53_ldb_prepare(struct imx_ldb_channel *imx_ldb_ch, int di)
 	diclk = clk_lookup(clkname);
 	free(clkname);
 	if (IS_ERR(diclk)) {
-		dev_err(ldb->dev, "failed to get di clk: %s\n", strerror(PTR_ERR(diclk)));
+		dev_err(ldb->dev, "failed to get di clk: %s\n", strerrorp(diclk));
 		return PTR_ERR(diclk);
 	}
 
@@ -224,7 +224,7 @@ static int imx53_ldb_prepare(struct imx_ldb_channel *imx_ldb_ch, int di)
 	ldbclk = clk_lookup(clkname);
 	free(clkname);
 	if (IS_ERR(ldbclk)) {
-		dev_err(ldb->dev, "failed to get ldb clk: %s\n", strerror(PTR_ERR(ldbclk)));
+		dev_err(ldb->dev, "failed to get ldb clk: %s\n", strerrorp(ldbclk));
 		return PTR_ERR(ldbclk);
 	}
 
diff --git a/fs/ubifs/ubifs.c b/fs/ubifs/ubifs.c
index a9189f7..4368203 100644
--- a/fs/ubifs/ubifs.c
+++ b/fs/ubifs/ubifs.c
@@ -622,7 +622,7 @@ static int ubifs_probe(struct device_d *dev)
 	priv->ubi = ubi_open_volume_cdev(priv->cdev, UBI_READONLY);
 	if (IS_ERR(priv->ubi)) {
 		dev_err(dev, "failed to open ubi volume: %s\n",
-				strerror(-PTR_ERR(priv->ubi)));
+				strerrorp(priv->ubi));
 		ret = PTR_ERR(priv->ubi);
 		goto err_free;
 	}
diff --git a/include/errno.h b/include/errno.h
index 025816e..496ccab 100644
--- a/include/errno.h
+++ b/include/errno.h
@@ -2,6 +2,7 @@
 #define __ERRNO_H
 
 #include <asm-generic/errno.h>
+#include <linux/err.h>
 
 extern int errno;
 
@@ -9,4 +10,9 @@ void perror(const char *s);
 const char *errno_str(void);
 const char *strerror(int errnum);
 
+static inline const char *strerrorp(const void *errp)
+{
+	return strerror(-PTR_ERR(errp));
+}
+
 #endif /* __ERRNO_H */
-- 
2.5.1