diff mbox series

[v2,4/5] driver core: Add device probe log helper dev_warn_probe()

Message ID 2fd9a60e0efe906dc7a203cd652c8d0b7f932470.1727496560.git.dsimic@manjaro.org (mailing list archive)
State New, archived
Headers show
Series Add dev_warn_probe() and improve error handling in Rockchip SPI drivers | expand

Commit Message

Dragan Simic Sept. 28, 2024, 4:12 a.m. UTC 
Some drivers can still provide their functionality to a certain extent even
some of their resource acquisitions eventually fail.  In such cases, emitting
errors isn't the desired action, but warnings should be emitted instead.

To solve this, introduce dev_warn_probe() as a new device probe log helper,
which behaves identically as the already existing dev_err_probe(), while it
produces warnings instead of errors.  The intended use is with the resources
that are actually optional for a particular driver.

While there, copyedit the kerneldoc for dev_err_probe() a bit, to simplify
its wording a bit, and reuse it as the kerneldoc for dev_warn_probe(), with
the necessary wording adjustments, of course.

Signed-off-by: Dragan Simic <dsimic@manjaro.org>
---
 drivers/base/core.c        | 110 ++++++++++++++++++++++++++++---------
 include/linux/dev_printk.h |   1 +
 2 files changed, 84 insertions(+), 27 deletions(-)

Comments

kernel test robot Sept. 29, 2024, 1:39 a.m. UTC | #1 
Hi Dragan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on rockchip/for-next]
[also build test WARNING on broonie-spi/for-next driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus linus/master v6.11 next-20240927]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Dragan-Simic/spi-rockchip-Perform-trivial-code-cleanups/20240928-121548
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git for-next
patch link:    https://lore.kernel.org/r/2fd9a60e0efe906dc7a203cd652c8d0b7f932470.1727496560.git.dsimic%40manjaro.org
patch subject: [PATCH v2 4/5] driver core: Add device probe log helper dev_warn_probe()
config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20240929/202409290956.jwLrcN1S-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240929/202409290956.jwLrcN1S-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409290956.jwLrcN1S-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/base/core.c: In function 'dev_err_probe':
>> drivers/base/core.c:5055:1: warning: control reaches end of non-void function [-Wreturn-type]
    5055 | }
         | ^
   drivers/base/core.c: In function 'dev_warn_probe':
   drivers/base/core.c:5101:1: warning: control reaches end of non-void function [-Wreturn-type]
    5101 | }
         | ^


vim +5055 drivers/base/core.c

  5011	
  5012	/**
  5013	 * dev_err_probe - probe error check and log helper
  5014	 * @dev: the pointer to the struct device
  5015	 * @err: error value to test
  5016	 * @fmt: printf-style format string
  5017	 * @...: arguments as specified in the format string
  5018	 *
  5019	 * This helper implements common pattern present in probe functions for error
  5020	 * checking: print debug or error message depending if the error value is
  5021	 * -EPROBE_DEFER and propagate error upwards.
  5022	 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
  5023	 * checked later by reading devices_deferred debugfs attribute.
  5024	 * It replaces the following code sequence::
  5025	 *
  5026	 * 	if (err != -EPROBE_DEFER)
  5027	 * 		dev_err(dev, ...);
  5028	 * 	else
  5029	 * 		dev_dbg(dev, ...);
  5030	 * 	return err;
  5031	 *
  5032	 * with::
  5033	 *
  5034	 * 	return dev_err_probe(dev, err, ...);
  5035	 *
  5036	 * Using this helper in your probe function is totally fine even if @err
  5037	 * is known to never be -EPROBE_DEFER.
  5038	 * The benefit compared to a normal dev_err() is the standardized format
  5039	 * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
  5040	 * instead of "-35"), and having the error code returned allows more
  5041	 * compact error paths.
  5042	 *
  5043	 * Returns @err.
  5044	 */
  5045	int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
  5046	{
  5047		va_list args;
  5048	
  5049		va_start(args, fmt);
  5050	
  5051		/* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */
  5052		dev_probe_failed(dev, err, true, fmt, args);
  5053	
  5054		va_end(args);
> 5055	}
  5056	EXPORT_SYMBOL_GPL(dev_err_probe);
  5057
kernel test robot Sept. 29, 2024, 2:10 a.m. UTC | #2 
Hi Dragan,

kernel test robot noticed the following build errors:

[auto build test ERROR on rockchip/for-next]
[also build test ERROR on broonie-spi/for-next driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus linus/master v6.11 next-20240927]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Dragan-Simic/spi-rockchip-Perform-trivial-code-cleanups/20240928-121548
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git for-next
patch link:    https://lore.kernel.org/r/2fd9a60e0efe906dc7a203cd652c8d0b7f932470.1727496560.git.dsimic%40manjaro.org
patch subject: [PATCH v2 4/5] driver core: Add device probe log helper dev_warn_probe()
config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20240929/202409290914.ODQyF8lR-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 7773243d9916f98ba0ffce0c3a960e4aa9f03e81)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240929/202409290914.ODQyF8lR-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409290914.ODQyF8lR-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   In file included from drivers/base/core.c:11:
   In file included from include/linux/acpi.h:14:
   In file included from include/linux/device.h:32:
   In file included from include/linux/device/driver.h:21:
   In file included from include/linux/module.h:19:
   In file included from include/linux/elf.h:6:
   In file included from arch/s390/include/asm/elf.h:181:
   In file included from arch/s390/include/asm/mmu_context.h:11:
   In file included from arch/s390/include/asm/pgalloc.h:18:
   In file included from include/linux/mm.h:2228:
   include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   In file included from drivers/base/core.c:27:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
   In file included from include/linux/dma-mapping.h:11:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:93:
   include/asm-generic/io.h:548:31: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     548 |         val = __raw_readb(PCI_IOBASE + addr);
         |                           ~~~~~~~~~~ ^
   include/asm-generic/io.h:561:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     561 |         val = __le16_to_cpu((__le16 __force)__raw_readw(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:37:59: note: expanded from macro '__le16_to_cpu'
      37 | #define __le16_to_cpu(x) __swab16((__force __u16)(__le16)(x))
         |                                                           ^
   include/uapi/linux/swab.h:102:54: note: expanded from macro '__swab16'
     102 | #define __swab16(x) (__u16)__builtin_bswap16((__u16)(x))
         |                                                      ^
   In file included from drivers/base/core.c:27:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
   In file included from include/linux/dma-mapping.h:11:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:93:
   include/asm-generic/io.h:574:61: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     574 |         val = __le32_to_cpu((__le32 __force)__raw_readl(PCI_IOBASE + addr));
         |                                                         ~~~~~~~~~~ ^
   include/uapi/linux/byteorder/big_endian.h:35:59: note: expanded from macro '__le32_to_cpu'
      35 | #define __le32_to_cpu(x) __swab32((__force __u32)(__le32)(x))
         |                                                           ^
   include/uapi/linux/swab.h:115:54: note: expanded from macro '__swab32'
     115 | #define __swab32(x) (__u32)__builtin_bswap32((__u32)(x))
         |                                                      ^
   In file included from drivers/base/core.c:27:
   In file included from include/linux/netdevice.h:38:
   In file included from include/net/net_namespace.h:43:
   In file included from include/linux/skbuff.h:28:
   In file included from include/linux/dma-mapping.h:11:
   In file included from include/linux/scatterlist.h:9:
   In file included from arch/s390/include/asm/io.h:93:
   include/asm-generic/io.h:585:33: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     585 |         __raw_writeb(value, PCI_IOBASE + addr);
         |                             ~~~~~~~~~~ ^
   include/asm-generic/io.h:595:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     595 |         __raw_writew((u16 __force)cpu_to_le16(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:605:59: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     605 |         __raw_writel((u32 __force)cpu_to_le32(value), PCI_IOBASE + addr);
         |                                                       ~~~~~~~~~~ ^
   include/asm-generic/io.h:693:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     693 |         readsb(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:701:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     701 |         readsw(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:709:20: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     709 |         readsl(PCI_IOBASE + addr, buffer, count);
         |                ~~~~~~~~~~ ^
   include/asm-generic/io.h:718:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     718 |         writesb(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:727:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     727 |         writesw(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
   include/asm-generic/io.h:736:21: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
     736 |         writesl(PCI_IOBASE + addr, buffer, count);
         |                 ~~~~~~~~~~ ^
>> drivers/base/core.c:4988:9: error: incompatible pointer types assigning to 'va_list *' (aka '__builtin_va_list *') from 'struct __va_list_tag **' [-Werror,-Wincompatible-pointer-types]
    4988 |         vaf.va = &args;
         |                ^ ~~~~~
>> drivers/base/core.c:5055:1: warning: non-void function does not return a value [-Wreturn-type]
    5055 | }
         | ^
   drivers/base/core.c:5101:1: warning: non-void function does not return a value [-Wreturn-type]
    5101 | }
         | ^
   15 warnings and 1 error generated.


vim +4988 drivers/base/core.c

  4981	
  4982	static int dev_probe_failed(const struct device *dev, int err, bool fatal,
  4983				    const char *fmt, va_list args)
  4984	{
  4985		struct va_format vaf;
  4986	
  4987		vaf.fmt = fmt;
> 4988		vaf.va = &args;
  4989	
  4990		switch (err) {
  4991		case -EPROBE_DEFER:
  4992			device_set_deferred_probe_reason(dev, &vaf);
  4993			dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
  4994			break;
  4995	
  4996		case -ENOMEM:
  4997			/* Don't print anything on -ENOMEM, there's already enough output */
  4998			break;
  4999	
  5000		default:
  5001			/* Log fatal final failures as errors, otherwise produce warnings */
  5002			if (fatal)
  5003				dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
  5004			else
  5005				dev_warn(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
  5006			break;
  5007		}
  5008	
  5009		return err;
  5010	}
  5011	
  5012	/**
  5013	 * dev_err_probe - probe error check and log helper
  5014	 * @dev: the pointer to the struct device
  5015	 * @err: error value to test
  5016	 * @fmt: printf-style format string
  5017	 * @...: arguments as specified in the format string
  5018	 *
  5019	 * This helper implements common pattern present in probe functions for error
  5020	 * checking: print debug or error message depending if the error value is
  5021	 * -EPROBE_DEFER and propagate error upwards.
  5022	 * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
  5023	 * checked later by reading devices_deferred debugfs attribute.
  5024	 * It replaces the following code sequence::
  5025	 *
  5026	 * 	if (err != -EPROBE_DEFER)
  5027	 * 		dev_err(dev, ...);
  5028	 * 	else
  5029	 * 		dev_dbg(dev, ...);
  5030	 * 	return err;
  5031	 *
  5032	 * with::
  5033	 *
  5034	 * 	return dev_err_probe(dev, err, ...);
  5035	 *
  5036	 * Using this helper in your probe function is totally fine even if @err
  5037	 * is known to never be -EPROBE_DEFER.
  5038	 * The benefit compared to a normal dev_err() is the standardized format
  5039	 * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
  5040	 * instead of "-35"), and having the error code returned allows more
  5041	 * compact error paths.
  5042	 *
  5043	 * Returns @err.
  5044	 */
  5045	int dev_err_probe(const struct device *dev, int err, const char *fmt, ...)
  5046	{
  5047		va_list args;
  5048	
  5049		va_start(args, fmt);
  5050	
  5051		/* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */
  5052		dev_probe_failed(dev, err, true, fmt, args);
  5053	
  5054		va_end(args);
> 5055	}
  5056	EXPORT_SYMBOL_GPL(dev_err_probe);
  5057
kernel test robot Sept. 29, 2024, 2:20 a.m. UTC | #3 
Hi Dragan,

kernel test robot noticed the following build errors:

[auto build test ERROR on rockchip/for-next]
[also build test ERROR on broonie-spi/for-next driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus linus/master v6.11 next-20240927]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Dragan-Simic/spi-rockchip-Perform-trivial-code-cleanups/20240928-121548
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git for-next
patch link:    https://lore.kernel.org/r/2fd9a60e0efe906dc7a203cd652c8d0b7f932470.1727496560.git.dsimic%40manjaro.org
patch subject: [PATCH v2 4/5] driver core: Add device probe log helper dev_warn_probe()
config: powerpc-allnoconfig (https://download.01.org/0day-ci/archive/20240929/202409290910.55WdSCMH-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240929/202409290910.55WdSCMH-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202409290910.55WdSCMH-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/base/core.c: In function 'dev_probe_failed':
>> drivers/base/core.c:4988:16: error: assignment to '__va_list_tag (*)[1]' from incompatible pointer type '__va_list_tag **' [-Wincompatible-pointer-types]
    4988 |         vaf.va = &args;
         |                ^
   drivers/base/core.c: In function 'dev_err_probe':
   drivers/base/core.c:5055:1: warning: control reaches end of non-void function [-Wreturn-type]
    5055 | }
         | ^
   drivers/base/core.c: In function 'dev_warn_probe':
   drivers/base/core.c:5101:1: warning: control reaches end of non-void function [-Wreturn-type]
    5101 | }
         | ^


vim +4988 drivers/base/core.c

  4981	
  4982	static int dev_probe_failed(const struct device *dev, int err, bool fatal,
  4983				    const char *fmt, va_list args)
  4984	{
  4985		struct va_format vaf;
  4986	
  4987		vaf.fmt = fmt;
> 4988		vaf.va = &args;
  4989	
  4990		switch (err) {
  4991		case -EPROBE_DEFER:
  4992			device_set_deferred_probe_reason(dev, &vaf);
  4993			dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
  4994			break;
  4995	
  4996		case -ENOMEM:
  4997			/* Don't print anything on -ENOMEM, there's already enough output */
  4998			break;
  4999	
  5000		default:
  5001			/* Log fatal final failures as errors, otherwise produce warnings */
  5002			if (fatal)
  5003				dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
  5004			else
  5005				dev_warn(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
  5006			break;
  5007		}
  5008	
  5009		return err;
  5010	}
  5011
diff mbox series

Patch

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 8c0733d3aad8..a4592b7ffa5d 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -4982,71 +4982,127 @@  define_dev_printk_level(_dev_info, KERN_INFO);
 
 #endif
 
+static int dev_probe_failed(const struct device *dev, int err, bool fatal,
+			    const char *fmt, va_list args)
+{
+	struct va_format vaf;
+
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	switch (err) {
+	case -EPROBE_DEFER:
+		device_set_deferred_probe_reason(dev, &vaf);
+		dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
+		break;
+
+	case -ENOMEM:
+		/* Don't print anything on -ENOMEM, there's already enough output */
+		break;
+
+	default:
+		/* Log fatal final failures as errors, otherwise produce warnings */
+		if (fatal)
+			dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
+		else
+			dev_warn(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
+		break;
+	}
+
+	return err;
+}
+
 /**
  * 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.
  * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
  * checked later by reading devices_deferred debugfs attribute.
- * It replaces code sequence::
+ * It replaces the following code sequence::
  *
  * 	if (err != -EPROBE_DEFER)
  * 		dev_err(dev, ...);
  * 	else
  * 		dev_dbg(dev, ...);
  * 	return err;
  *
  * with::
  *
  * 	return dev_err_probe(dev, err, ...);
  *
- * Using this helper in your probe function is totally fine even if @err is
- * known to never be -EPROBE_DEFER.
+ * Using this helper in your probe function is totally fine even if @err
+ * is known to never be -EPROBE_DEFER.
  * The benefit compared to a normal dev_err() is the standardized format
- * of the error code, it being emitted symbolically (i.e. you get "EAGAIN"
- * instead of "-35") and the fact that the error code is returned which allows
- * more compact error paths.
+ * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
+ * instead of "-35"), and having the error code returned allows more
+ * compact error paths.
  *
  * 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;
 
-	switch (err) {
-	case -EPROBE_DEFER:
-		device_set_deferred_probe_reason(dev, &vaf);
-		dev_dbg(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
-		break;
+	/* Use dev_err() for logging when err doesn't equal -EPROBE_DEFER */
+	dev_probe_failed(dev, err, true, fmt, args);
 
-	case -ENOMEM:
-		/*
-		 * We don't print anything on -ENOMEM, there is already enough
-		 * output.
-		 */
-		break;
+	va_end(args);
+}
+EXPORT_SYMBOL_GPL(dev_err_probe);
 
-	default:
-		dev_err(dev, "error %pe: %pV", ERR_PTR(err), &vaf);
-		break;
-	}
+/**
+ * dev_warn_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 warning message depending if the error value is
+ * -EPROBE_DEFER and propagate error upwards.
+ * In case of -EPROBE_DEFER it sets also defer probe reason, which can be
+ * checked later by reading devices_deferred debugfs attribute.
+ * It replaces the following code sequence::
+ *
+ * 	if (err != -EPROBE_DEFER)
+ * 		dev_warn(dev, ...);
+ * 	else
+ * 		dev_dbg(dev, ...);
+ * 	return err;
+ *
+ * with::
+ *
+ * 	return dev_warn_probe(dev, err, ...);
+ *
+ * Using this helper in your probe function is totally fine even if @err
+ * is known to never be -EPROBE_DEFER.
+ * The benefit compared to a normal dev_warn() is the standardized format
+ * of the error code, which is emitted symbolically (i.e. you get "EAGAIN"
+ * instead of "-35"), and having the error code returned allows more
+ * compact error paths.
+ *
+ * Returns @err.
+ */
+int dev_warn_probe(const struct device *dev, int err, const char *fmt, ...)
+{
+	va_list args;
 
-	va_end(args);
+	va_start(args, fmt);
 
-	return err;
+	/* Use dev_warn() for logging when err doesn't equal -EPROBE_DEFER */
+	dev_probe_failed(dev, err, false, fmt, args);
+
+	va_end(args);
 }
-EXPORT_SYMBOL_GPL(dev_err_probe);
+EXPORT_SYMBOL_GPL(dev_warn_probe);
 
 static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
 {
diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h
index ca32b5bb28eb..eb2094e43050 100644
--- a/include/linux/dev_printk.h
+++ b/include/linux/dev_printk.h
@@ -276,6 +276,7 @@  do {									\
 			dev_driver_string(dev), dev_name(dev), ## arg)
 
 __printf(3, 4) int dev_err_probe(const struct device *dev, int err, const char *fmt, ...);
+__printf(3, 4) int dev_warn_probe(const struct device *dev, int err, const char *fmt, ...);
 
 /* Simple helper for dev_err_probe() when ERR_PTR() is to be returned. */
 #define dev_err_ptr_probe(dev, ___err, fmt, ...) \