linux-kernel - [PATCH 1/3] driver core: add probe

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-id: <20181016072244.1216-2-a.hajda@samsung.com>
Date:   Tue, 16 Oct 2018 09:22:42 +0200
From:   Andrzej Hajda <a.hajda@...sung.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Andrzej Hajda <a.hajda@...sung.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        linux-kernel@...r.kernel.org,
        Javier Martinez Canillas <javierm@...hat.com>,
        linux-arm-kernel@...ts.infradead.org, andy.shevchenko@...il.com,
        Mark Brown <broonie@...nel.org>
Subject: [PATCH 1/3] driver core: add probe_err log helper

During probe every time driver gets resource it should usually check for error
printk some message if it is not -EPROBE_DEFER and return the error. This
pattern is simple but requires adding few lines after any resource acquisition
code, as a result it is often omited or implemented only partially.
probe_err helps to replace such code seqences with simple call, so code:
	if (err != -EPROBE_DEFER)
		dev_err(dev, ...);
	return err;
becomes:
	return probe_err(dev, err, ...);

Signed-off-by: Andrzej Hajda <a.hajda@...sung.com>
---
 drivers/base/core.c    | 37 +++++++++++++++++++++++++++++++++++++
 include/linux/device.h |  2 ++
 2 files changed, 39 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 04bbcd779e11..23fabefb217a 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -3067,6 +3067,43 @@ define_dev_printk_level(_dev_info, KERN_INFO);
 
 #endif
 
+/**
+ * probe_err - probe error check and log helper
+ * @dev: the pointer to the struct device
+ * @err: error value to test
+ * @fmt: printf-style format string
+ * @...: arguments as specified in the format string
+ *
+ * This helper implements common pattern present in probe functions for error
+ * checking: print message if the error is not -EPROBE_DEFER and propagate it.
+ * It replaces code sequence:
+ * 	if (err != -EPROBE_DEFER)
+ * 		dev_err(dev, ...);
+ * 	return err;
+ * with
+ * 	return probe_err(dev, err, ...);
+ *
+ * Returns @err.
+ *
+ */
+int probe_err(const struct device *dev, int err, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+
+	if (err != -EPROBE_DEFER) {
+		va_start(args, fmt);
+
+		vaf.fmt = fmt;
+		vaf.va = &args;
+
+		__dev_printk(KERN_ERR, dev, &vaf);
+		va_end(args);
+	}
+
+	return err;
+}
+
 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
 {
 	return fwnode && !IS_ERR(fwnode->secondary);
diff --git a/include/linux/device.h b/include/linux/device.h
index 90224e75ade4..06c2c797d132 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -1577,6 +1577,8 @@ do {									\
 	WARN_ONCE(condition, "%s %s: " format, \
 			dev_driver_string(dev), dev_name(dev), ## arg)
 
+int probe_err(const struct device *dev, int err, const char *fmt, ...);
+
 /* Create alias, so I can be autoloaded. */
 #define MODULE_ALIAS_CHARDEV(major,minor) \
 	MODULE_ALIAS("char-major-" __stringify(major) "-" __stringify(minor))
-- 
2.18.0