[PATCH v2][next] scsi: sd: Avoid -Wflex-array-member-not-at-end warning

Gustavo A. R. Silva
2025-05-01T18:39:32Z

Apparently, the flexible-array member in `struct scsi_stream_status_header`
is not actually needed. Remove it along with the related KUnit test.

So, with these changes, fix the following warning:

drivers/scsi/sd.c:3195:50: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]

Co-developed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
Changes in v2:
- Revome flexible-array member. (Christoph)

v1:
- Link: https://lore.kernel.org/linux-hardening/aAwos0mLxneG9R_t@kspp/

drivers/scsi/scsi_proto_test.c | 8 --------
drivers/scsi/sd.c | 2 +-
include/scsi/scsi_proto.h | 1 -
3 files changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/scsi/scsi_proto_test.c b/drivers/scsi/scsi_proto_test.c
index c093389edabb..2fc5c6523184 100644
--- a/drivers/scsi/scsi_proto_test.c
+++ b/drivers/scsi/scsi_proto_test.c
@@ -30,14 +30,6 @@ static void test_scsi_proto(struct kunit *test)
KUNIT_EXPECT_EQ(test, get_unaligned_be16(&ss.s.stream_identifier),
0x1234);
KUNIT_EXPECT_EQ(test, ss.s.rel_lifetime + 0, 0x3f);
-
- static const union {
- struct scsi_stream_status_header h;
- u8 arr[sizeof(struct scsi_stream_status_header)];
- } sh = { .arr = { 1, 2, 3, 4, 0, 0, 5, 6 } };
- KUNIT_EXPECT_EQ(test, get_unaligned_be32(&sh.h.len), 0x1020304);
- KUNIT_EXPECT_EQ(test, get_unaligned_be16(&sh.h.number_of_open_streams),
- 0x506);
}

static struct kunit_case scsi_proto_test_cases[] = {
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 950d8c9fb884..3f6e87705b62 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3215,7 +3215,7 @@ static bool sd_is_perm_stream(struct scsi_disk *sdkp, unsigned int stream_id)
return false;
if (get_unaligned_be32(&buf.h.len) < sizeof(struct scsi_stream_status))
return false;
- return buf.h.stream_status[0].perm;
+ return buf.s.perm;
}

static void sd_read_io_hints(struct scsi_disk *sdkp, unsigned char *buffer)
diff --git a/include/scsi/scsi_proto.h b/include/scsi/scsi_proto.h
index aeca37816506..bc8f2b2226be 100644
--- a/include/scsi/scsi_proto.h
+++ b/include/scsi/scsi_proto.h
@@ -349,7 +349,6 @@ struct scsi_stream_status_header {
__be32 len; /* length in bytes of stream_status[] array. */
u16 reserved;
__be16 number_of_open_streams;
- DECLARE_FLEX_ARRAY(struct scsi_stream_status, stream_status);
};

static_assert(sizeof(struct scsi_stream_status_header) == 8);
--
2.43.0