[ndctl,01/16] ndctl/build: Fix zero-length array warnings

Commit Message

Dan Williams July 7, 2020, 2:40 a.m. UTC

GCC10 emits warnings like:

msft.c: In function ‘msft_cmd_smart_get_media_temperature’:
msft.c:146:28: warning: array subscript 0 is outside the bounds of an interior zero-length array ‘struct ndn_msft_smart_data[0]’ [-Wzero-length-bounds]

hpe1.c: In function ‘hpe1_cmd_smart_get_flags’:
hpe1.c:111:33: warning: array subscript 0 is outside the bounds of an interior zero-length array ‘struct ndn_hpe1_smart_data[0]’ [-Wzero-length-bounds]

ars.c: In function ‘ndctl_cmd_ars_get_record_addr’:
ars.c:274:38: warning: array subscript ‘(<unknown>) + 4294967295’ is outside the bounds of an interior zero-length array ‘struct nd_ars_record[0]’ [-Wzero-length-bounds]

In the case of the 'msft' and 'hpe1' implementation the zero-length array
is not needed because they are declared with a union of a buffer of the
same size as a single element. Fix those cases by just declaring a single
element array.

The ARS case is different, it's complaining about an internal zero-length
member. Switch to the recommended [1] flexible-array syntax for that case.

[1]: https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html

Signed-off-by: Dan Williams <[e-mail]>
---
 ndctl/lib/hpe1.h |    4 ++--
 ndctl/lib/msft.h |    2 +-
 ndctl/ndctl.h    |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

Patch

diff --git a/ndctl/lib/hpe1.h b/ndctl/lib/hpe1.h
index b050831ec2c4..1afa54f127a6 100644
--- a/ndctl/lib/hpe1.h
+++ b/ndctl/lib/hpe1.h
@@ -111,7 +111,7 @@  struct ndn_hpe1_smart {
 	__u32 status;
 	union {
 		__u8 buf[124];
-		struct ndn_hpe1_smart_data data[0];
+		struct ndn_hpe1_smart_data data[1];
 	};
 } __attribute__((packed));
 
@@ -136,7 +136,7 @@  struct ndn_hpe1_smart_threshold {
 	__u32 status;
 	union {
 		__u8 buf[32];
-		struct ndn_hpe1_smart_threshold_data data[0];
+		struct ndn_hpe1_smart_threshold_data data[1];
 	};
 } __attribute__((packed));
 
diff --git a/ndctl/lib/msft.h b/ndctl/lib/msft.h
index 0a1c7c6a0907..c45981edd8d7 100644
--- a/ndctl/lib/msft.h
+++ b/ndctl/lib/msft.h
@@ -46,7 +46,7 @@  struct ndn_msft_smart {
 	__u32	status;
 	union {
 		__u8 buf[9];
-		struct ndn_msft_smart_data data[0];
+		struct ndn_msft_smart_data data[1];
 	};
 } __attribute__((packed));
 
diff --git a/ndctl/ndctl.h b/ndctl/ndctl.h
index 008f81cdeb9f..e3605b3d64b4 100644
--- a/ndctl/ndctl.h
+++ b/ndctl/ndctl.h
@@ -91,7 +91,7 @@  struct nd_cmd_ars_status {
 		__u32 reserved;
 		__u64 err_address;
 		__u64 length;
-	} __attribute__((packed)) records[0];
+	} __attribute__((packed)) records[];
 } __attribute__((packed));
 
 struct nd_cmd_clear_error {