| Message ID | aAwos0mLxneG9R_t@kspp |
|---|---|
| State | New |
| Headers | show |
| Series | [next] scsi: sd: Avoid -Wflex-array-member-not-at-end warning | expand |
On Fri, Apr 25, 2025 at 06:28:35PM -0600, Gustavo A. R. Silva wrote: > -Wflex-array-member-not-at-end was introduced in GCC-14, and we are > getting ready to enable it, globally. > > Use the `DEFINE_RAW_FLEX()` helper for on-stack definitions of > a flexible structure where the size of the flexible-array member > is known at compile-time, and refactor the rest of the code, > accordingly. > > Also, there is no need to use the DECLARE_FLEX_ARRAY() helper. > Replace it with a regular flexible-array member declaration > instead. > > 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] > > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> Looks good; thanks! Reviewed-by: Kees Cook <kees@kernel.org>
Yikes. This is way to ugly to live. Just remove the silly flex
array entirely and everyone is better off:
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);
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 950d8c9fb884..aa15b1085235 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3191,10 +3191,7 @@ sd_read_cache_type(struct scsi_disk *sdkp, unsigned char *buffer) static bool sd_is_perm_stream(struct scsi_disk *sdkp, unsigned int stream_id) { u8 cdb[16] = { SERVICE_ACTION_IN_16, SAI_GET_STREAM_STATUS }; - struct { - struct scsi_stream_status_header h; - struct scsi_stream_status s; - } buf; + DEFINE_RAW_FLEX(struct scsi_stream_status_header, buf, stream_status, 1); struct scsi_device *sdev = sdkp->device; struct scsi_sense_hdr sshdr; const struct scsi_exec_args exec_args = { @@ -3203,9 +3200,9 @@ static bool sd_is_perm_stream(struct scsi_disk *sdkp, unsigned int stream_id) int res; put_unaligned_be16(stream_id, &cdb[4]); - put_unaligned_be32(sizeof(buf), &cdb[10]); + put_unaligned_be32(__struct_size(buf), &cdb[10]); - res = scsi_execute_cmd(sdev, cdb, REQ_OP_DRV_IN, &buf, sizeof(buf), + res = scsi_execute_cmd(sdev, cdb, REQ_OP_DRV_IN, buf, __struct_size(buf), SD_TIMEOUT, sdkp->max_retries, &exec_args); if (res < 0) return false; @@ -3213,9 +3210,9 @@ static bool sd_is_perm_stream(struct scsi_disk *sdkp, unsigned int stream_id) sd_print_sense_hdr(sdkp, &sshdr); if (res) return false; - if (get_unaligned_be32(&buf.h.len) < sizeof(struct scsi_stream_status)) + if (get_unaligned_be32(&buf->len) < sizeof(struct scsi_stream_status)) return false; - return buf.h.stream_status[0].perm; + return buf->stream_status[0].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..0ae7adc8a5db 100644 --- a/include/scsi/scsi_proto.h +++ b/include/scsi/scsi_proto.h @@ -349,7 +349,7 @@ 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); + struct scsi_stream_status stream_status[]; }; static_assert(sizeof(struct scsi_stream_status_header) == 8);
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are getting ready to enable it, globally. Use the `DEFINE_RAW_FLEX()` helper for on-stack definitions of a flexible structure where the size of the flexible-array member is known at compile-time, and refactor the rest of the code, accordingly. Also, there is no need to use the DECLARE_FLEX_ARRAY() helper. Replace it with a regular flexible-array member declaration instead. 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] Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- drivers/scsi/sd.c | 13 +++++-------- include/scsi/scsi_proto.h | 2 +- 2 files changed, 6 insertions(+), 9 deletions(-)