Re: [PATCH blktests] src/dio-offsets.c: Fix err() usage

[Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>]

On Mar 26, 2026 / 10:36, Bart Van Assche wrote:
> If the dio-offsets program detects data corruption, it reports the
> following message:
> 
> dio-offsets: test_unaligned_vectors: data corruption: Success
> 
> The "Success" part in this message is confusing and is reported because
> the err() macro is used incorrectly. errno must be set before err() is
> used instead of passing an error number as first argument. Fix usage of
> the err() macro as follows:
> - Change the first argument into EXIT_FAILURE (1). According to POSIX,
>   exit codes 1 - 125 mean failure and > 128 means that a program was
>   terminated by a signal. Hence, exit with code 1 instead of -1 if
>   ioctl() fails.
> - Use the err_errno() macro to set the error code instead of passing an
>   error code as first argument to err().

Bart, thanks for the patch. Overall, it looks good to me.

One thing I found is that one more err(EIO,...) is left in __compare() after
applying the patch. Should we convert it also into err_errno()? If so, I will
fold-in the hunk below.

diff --git a/src/dio-offsets.c b/src/dio-offsets.c
index 9fc7b92..c40ce68 100644
--- a/src/dio-offsets.c
+++ b/src/dio-offsets.c
@@ -131,7 +131,7 @@ static void __compare(void *a, void *b, size_t size, const char *test)
 {
 	if (!memcmp(a, b, size))
 		return;
-	err(EIO, "%s: data corruption", test);
+	err_errno(EIO, "%s: data corruption", test);
 }
 #define compare(a, b, size) __compare(a, b, size, __func__)