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

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

[Bart Van Assche]

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().

Cc: Keith Busch <kbusch@kernel.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 src/dio-offsets.c | 99 +++++++++++++++++++++++++++--------------------
 1 file changed, 56 insertions(+), 43 deletions(-)

diff --git a/src/dio-offsets.c b/src/dio-offsets.c
index 4d9c71c83798..9fc7b9247b99 100644
--- a/src/dio-offsets.c
+++ b/src/dio-offsets.c
@@ -26,6 +26,11 @@
 #include <sys/mount.h>
 
 #define power_of_2(x) ((x) && !((x) & ((x) - 1)))
+#define err_errno(exit_code, ...)		\
+	do {					\
+		errno = (exit_code);		\
+		err(EXIT_FAILURE, __VA_ARGS__); \
+	} while (0)
 
 static unsigned long logical_block_size;
 static unsigned long dma_alignment;
@@ -42,7 +47,7 @@ static void init_args(char **argv)
 {
 	test_fd = open(argv[1], O_RDWR | O_TRUNC | O_DIRECT);
 	if (test_fd < 0)
-		err(errno, "%s: failed to open %s", __func__, argv[1]);
+		err(EXIT_FAILURE, "%s: failed to open %s", __func__, argv[1]);
 
 	max_segments = strtoul(argv[2], NULL, 0);
 	max_bytes = strtoul(argv[3], NULL, 0) * 1024;
@@ -54,18 +59,18 @@ static void init_args(char **argv)
 	    !power_of_2(dma_alignment) ||
 	    !power_of_2(logical_block_size)) {
 		errno = EINVAL;
-		err(1, "%s: bad parameters", __func__);
+		err(EXIT_FAILURE, "%s: bad parameters", __func__);
 	}
 
 	if (virt_boundary > 1 && virt_boundary < logical_block_size) {
 		errno = EINVAL;
-		err(1, "%s: virt_boundary:%lu logical_block_size:%lu", __func__,
+		err(EXIT_FAILURE, "%s: virt_boundary:%lu logical_block_size:%lu", __func__,
 			virt_boundary, logical_block_size);
 	}
 
 	if (dma_alignment > logical_block_size) {
 		errno = EINVAL;
-		err(1, "%s: dma_alignment:%lu logical_block_size:%lu", __func__,
+		err(EXIT_FAILURE, "%s: dma_alignment:%lu logical_block_size:%lu", __func__,
 			dma_alignment, logical_block_size);
 	}
 
@@ -87,7 +92,7 @@ static void init_buffers()
 
 	buf_size = max_bytes * max_segments / 2;
 	if (buf_size < logical_block_size * max_segments)
-		err(EINVAL, "%s: logical block size is too big", __func__);
+		err_errno(EINVAL, "%s: logical block size is too big", __func__);
 
 	if (buf_size < logical_block_size * 1024 * 4)
 		buf_size = logical_block_size * 1024 * 4;
@@ -97,26 +102,27 @@ static void init_buffers()
 
 	ret = ioctl(test_fd, BLKGETSIZE64, &dev_bytes);
 	if (ret < 0)
-		err(ret, "%s: ioctl BLKGETSIZE64 failed", __func__);
+		err(EXIT_FAILURE, "%s: ioctl BLKGETSIZE64 failed", __func__);
 
 	if (dev_bytes < buf_size)
 		buf_size = dev_bytes;
 
 	ret = posix_memalign((void **)&in_buf, pagesize, buf_size);
 	if (ret)
-		err(EINVAL, "%s: failed to allocate in-buf", __func__);
+		err_errno(EINVAL, "%s: failed to allocate in-buf", __func__);
 
 	ret = posix_memalign((void **)&out_buf, pagesize, buf_size);
 	if (ret)
-		err(EINVAL, "%s: failed to allocate out-buf", __func__);
+		err_errno(EINVAL, "%s: failed to allocate out-buf", __func__);
 
 	fd = open("/dev/urandom", O_RDONLY);
 	if (fd < 0)
-		err(EINVAL, "%s: failed to open urandom", __func__);
+		err_errno(EINVAL, "%s: failed to open urandom", __func__);
 
 	ret = read(fd, out_buf, buf_size);
 	if (ret < 0)
-		err(EINVAL, "%s: failed to randomize output buffer", __func__);
+		err_errno(EINVAL, "%s: failed to randomize output buffer",
+			  __func__);
 
 	close(fd);
 }
@@ -143,11 +149,11 @@ static void test_full_size_aligned()
 	memset(in_buf, 0, buf_size);
 	ret = pwrite(test_fd, out_buf, buf_size, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 
 	ret = pread(test_fd, in_buf, buf_size, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	compare(out_buf, in_buf, buf_size);
 }
@@ -164,11 +170,11 @@ static void test_dma_aligned()
 	memset(in_buf, 0, buf_size);
 	ret = pwrite(test_fd, out_buf + dma_alignment, max_bytes, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 
 	ret = pread(test_fd, in_buf + dma_alignment, max_bytes, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	compare(out_buf + dma_alignment, in_buf + dma_alignment, max_bytes);
 }
@@ -194,7 +200,7 @@ static void test_page_aligned_vectors()
 
 	ret = pwritev(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 
 	for (i = 0; i < vecs; i++) {
 		offset = logical_block_size * i * 4;
@@ -204,7 +210,7 @@ static void test_page_aligned_vectors()
 
 	ret = preadv(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	for (i = 0; i < vecs; i++) {
 		offset = logical_block_size * i * 4;
@@ -234,7 +240,7 @@ static void test_dma_aligned_vectors()
 
 	ret = pwritev(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 
 	for (i = 0; i < vecs; i++) {
 		offset = logical_block_size * i * 8 + dma_alignment * (i + 1);
@@ -244,7 +250,7 @@ static void test_dma_aligned_vectors()
 
 	ret = preadv(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	for (i = 0; i < vecs; i++) {
 		offset = logical_block_size * i * 8 + dma_alignment * (i + 1);
@@ -295,7 +301,7 @@ static void test_unaligned_page_vectors()
 	if (ret < 0) {
 		if (should_fail)
 			return;
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 	}
 
 	i = 0;
@@ -318,7 +324,7 @@ static void test_unaligned_page_vectors()
 
 	ret = preadv(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	i = 0;
 	offset = pagesize - (logical_block_size / 4);
@@ -367,7 +373,7 @@ static void test_unaligned_vectors()
 
 	ret = preadv(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	for (i = 0; i < vecs; i++) {
 		offset = logical_block_size * i * 8;
@@ -400,8 +406,9 @@ static void test_invalid_starting_addr()
 	if (ret < 0)
 		return;
 
-	err(ENOTSUP, "%s: write buf unexpectedly succeeded with NULL address ret:%d",
-		__func__, ret);
+	err_errno(ENOTSUP,
+		  "%s: write buf unexpectedly succeeded with NULL address ret:%d",
+		  __func__, ret);
 }
 
 /*
@@ -436,8 +443,9 @@ static void test_invalid_middle_addr()
 	if (ret < 0)
 		return;
 
-	err(ENOTSUP, "%s: write buf unexpectedly succeeded with NULL address ret:%d",
-		__func__, ret);
+	err_errno(ENOTSUP,
+		  "%s: write buf unexpectedly succeeded with NULL address ret:%d",
+		  __func__, ret);
 }
 
 /*
@@ -458,16 +466,17 @@ static void test_invalid_dma_alignment()
 	if (ret < 0) {
 		if (should_fail)
 			return;
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 	}
 
 	if (should_fail)
-		err(ENOTSUP, "%s: write buf unexpectedly succeeded with invalid DMA offset address, ret:%d",
-			__func__, ret);
+		err_errno(ENOTSUP,
+			  "%s: write buf unexpectedly succeeded with invalid DMA offset address, ret:%d",
+			  __func__, ret);
 
 	ret = pread(test_fd, in_buf + offset, size, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	compare(out_buf + offset, in_buf + offset, size);
 }
@@ -506,11 +515,12 @@ static void test_invalid_dma_vector_alignment()
 	if (ret < 0) {
 		if (should_fail)
 			return;
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 	}
 	if (should_fail)
-		err(ENOTSUP, "%s: write buf unexpectedly succeeded with invalid DMA offset address ret:%d",
-			__func__, ret);
+		err_errno(ENOTSUP,
+			  "%s: write buf unexpectedly succeeded with invalid DMA offset address ret:%d",
+			  __func__, ret);
 
 	iov[0].iov_base = in_buf;
 	iov[0].iov_len = max_bytes;
@@ -529,7 +539,7 @@ static void test_invalid_dma_vector_alignment()
 
 	ret = preadv(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	compare(out_buf, in_buf, max_bytes);
 	compare(out_buf + max_bytes * 2, in_buf + max_bytes * 2, max_bytes);
@@ -568,12 +578,13 @@ static void test_max_vector_limits()
 	if (ret < 0) {
 		if (should_fail)
 			return;
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 	}
 
 	if (should_fail)
-		err(ENOTSUP, "%s: write buf unexpectedly succeeded with excess vectors ret:%d",
-			__func__, ret);
+		err_errno(ENOTSUP,
+			  "%s: write buf unexpectedly succeeded with excess vectors ret:%d",
+			  __func__, ret);
 
 	for (i = 0; i < vecs; i++) {
 		offset = i * iov_size * 2;
@@ -583,7 +594,7 @@ static void test_max_vector_limits()
 
 	ret = preadv(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	for (i = 0; i < vecs; i++) {
 		offset = i * iov_size * 2;
@@ -622,8 +633,9 @@ static void test_invalid_dma_vector_alignment_large()
 	if (ret < 0)
 		return;
 
-	err(ENOTSUP, "%s: write buf unexpectedly succeeded with NULL address ret:%d",
-		__func__, ret);
+	err_errno(ENOTSUP,
+		  "%s: write buf unexpectedly succeeded with NULL address ret:%d",
+		  __func__, ret);
 }
 
 /*
@@ -656,12 +668,13 @@ static void test_invalid_dma_vector_length()
 	if (ret < 0) {
 		if (should_fail)
 			return;
-		err(errno, "%s: failed to write buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to write buf", __func__);
 	}
 
 	if (should_fail)
-		err(ENOTSUP, "%s: write buf unexpectedly succeeded with invalid DMA offset address ret:%d",
-			__func__, ret);
+		err_errno(ENOTSUP,
+			  "%s: write buf unexpectedly succeeded with invalid DMA offset address ret:%d",
+			  __func__, ret);
 
 	iov[0].iov_base = in_buf;
 	iov[0].iov_len = max_bytes * 2 - max_bytes / 2;
@@ -677,7 +690,7 @@ static void test_invalid_dma_vector_length()
 
 	ret = pwritev(test_fd, iov, vecs, 0);
 	if (ret < 0)
-		err(errno, "%s: failed to read buf", __func__);
+		err(EXIT_FAILURE, "%s: failed to read buf", __func__);
 
 	compare(out_buf, in_buf, iov[0].iov_len);
 	compare(out_buf + max_bytes * 4, in_buf + max_bytes * 4, iov[1].iov_len);

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

[Keith Busch]

On Thu, Mar 26, 2026 at 10:36:32AM -0700, 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().

Looks good:

Reviewed-by: Keith Busch <kbusch@kernel.org>

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

[Shinichiro Kawasaki]

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__)
 

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

[Bart Van Assche]

On 4/4/26 1:35 AM, Shinichiro Kawasaki wrote:
> 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__)

Folding in this change sounds good to me.

Thanks,

Bart.

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

[Shinichiro Kawasaki]

On Apr 06, 2026 / 06:51, Bart Van Assche wrote:
> On 4/4/26 1:35 AM, Shinichiro Kawasaki wrote:
> > 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__)
> 
> Folding in this change sounds good to me.

Thanks for the response. I applied the patch folding in the change.