Re: [PATCH v1 1/2] net: rfkill: Fix a wrongly handling error case

[quic_zijuhu <quic_zijuhu@quicinc.com>]

On 6/12/2024 4:15 PM, Johannes Berg wrote:
>>
>> use pr_err() instead of WARN()
>> for this error case handling.
> 
> I don't see anything wrong with the WARN here, it's the user/driver
> calling it completely incorrectly.
> 
the function is a kernel API and it is handing invalid user input.
below comments for WARN() seems say that pr_err() is better than WARN()
for this case.

include/asm-generic/bug.h:
/*
 * WARN(), WARN_ON(), WARN_ON_ONCE(), and so on can be used to report
 * significant kernel issues that need prompt attention if they should ever
 * appear at runtime.
 *
 * Do not use these macros when checking for invalid external inputs
 * (e.g. invalid system call arguments, or invalid data coming from
 * network/devices), and on transient conditions like ENOMEM or EAGAIN.
 * These macros should be used for recoverable kernel issues only.
 * For invalid external inputs, transient conditions, etc use
 * pr_err[_once/_ratelimited]() followed by dump_stack(), if necessary.
 * Do not include "BUG"/"WARNING" in format strings manually to make these
 * conditions distinguishable from kernel issues.
 *
 * Use the versions with printk format strings to provide better
diagnostics.
 */

> I also don't really think this is a *fix*, if you used the API
> incorrectly you can't necessarily expect a correct return value, I
> guess, but anyway it shouldn't happen in the first place.
> 
okay, will remove term fix and fix tag. the API returns type bool for
block state, the type bool can't cover case for invalid user input.

> I'm happy to take the return value change (only) as a cleanup, if you
> wish to resend that.
> 
i am pleasure to resend it after code review done.
>> Fixed by
> 
> Please also read
> https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
> 
okay, thank you
> johannes