Re: [PATCH v6 1/4] driver core: add device probe log helper

On Fri, Jun 26, 2020 at 12:01 PM Andrzej Hajda a.hajda@samsung.com wrote:

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 omitted or implemented only partially. dev_err_probe helps to replace such code sequences 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@samsung.com

Reviewed-by: Rafael J. Wysocki rafael@kernel.org

---

drivers/base/core.c | 42 ++++++++++++++++++++++++++++++++++++++++++ include/linux/device.h | 3 +++ 2 files changed, 45 insertions(+)

diff --git a/drivers/base/core.c b/drivers/base/core.c index 67d39a90b45c..3a827c82933f 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3953,6 +3953,48 @@ define_dev_printk_level(_dev_info, KERN_INFO);

#endif

+/**

• • dev_err_probe - 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 debug or error message depending if the error value is
• • -EPROBE_DEFER and propagate error upwards.
• • It replaces code sequence:

• • if (err != -EPROBE_DEFER)
    

• •         dev_err(dev, ...);
    

• • else
    

• •         dev_dbg(dev, ...);
    

• • return err;
    

• • with

• • return dev_err_probe(dev, err, ...);
    

• • Returns @err.
• */

+int dev_err_probe(const struct device *dev, int err, const char *fmt, ...) +{

•   struct va_format vaf;
  

•   va_list args;
  

•   va_start(args, fmt);
  

•   vaf.fmt = fmt;
  

•   vaf.va = &args;
  

•   if (err != -EPROBE_DEFER)
  

•           dev_err(dev, "error %d: %pV", err, &vaf);
  

•   else
  

•           dev_dbg(dev, "error %d: %pV", err, &vaf);
  

•   va_end(args);
  

•   return err;
  

+} +EXPORT_SYMBOL_GPL(dev_err_probe);

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 15460a5ac024..6b2272ae9af8 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -964,6 +964,9 @@ void device_link_remove(void *consumer, struct device *supplier); void device_links_supplier_sync_state_pause(void); void device_links_supplier_sync_state_resume(void);

+extern __printf(3, 4) +int dev_err_probe(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)) -- 2.17.1