treewide: uapi: Replace zero-length arrays with flexible-array members

There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(linux-5.19-rc2$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

-fstrict-flex-arrays=3 is coming and we need to land these changes
to prevent issues like these in the short future:

../fs/minix/dir.c:337:3: warning: 'strcpy' will always overflow; destination buffer has size 0,
but the source string has length 2 (including NUL byte) [-Wfortify-source]
		strcpy(de3->name, ".");
		^

Since these are all [0] to [] changes, the risk to UAPI is nearly zero. If
this breaks anything, we can use a union with a new member name.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Build-tested-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/
Acked-by: Dan Williams <dan.j.williams@intel.com> # For ndctl.h
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

4 files changed, 39 insertions, 39 deletions

diff --git a/include/uapi/rdma/hfi/hfi1_user.h b/include/uapi/rdma/hfi/hfi1_user.h
index d95ef9a2b032..1106a7c90b29 100644
--- a/include/uapi/rdma/hfi/hfi1_user.h
+++ b/include/uapi/rdma/hfi/hfi1_user.h
@@ -180,7 +180,7 @@ struct hfi1_sdma_comp_entry {
 struct hfi1_status {
 	__aligned_u64 dev;      /* device/hw status bits */
 	__aligned_u64 port;     /* port state and status bits */
-	char freezemsg[0];
+	char freezemsg[];
 };
 
 enum sdma_req_opcode {
diff --git a/include/uapi/rdma/ib_user_verbs.h b/include/uapi/rdma/ib_user_verbs.h
index 7dd903d932e5..43672cb1fd57 100644
--- a/include/uapi/rdma/ib_user_verbs.h
+++ b/include/uapi/rdma/ib_user_verbs.h
@@ -158,18 +158,18 @@ struct ib_uverbs_ex_cmd_hdr {
 
 struct ib_uverbs_get_context {
 	__aligned_u64 response;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_get_context_resp {
 	__u32 async_fd;
 	__u32 num_comp_vectors;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_query_device {
 	__aligned_u64 response;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_query_device_resp {
@@ -278,7 +278,7 @@ struct ib_uverbs_query_port {
 	__aligned_u64 response;
 	__u8  port_num;
 	__u8  reserved[7];
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_query_port_resp {
@@ -308,12 +308,12 @@ struct ib_uverbs_query_port_resp {
 
 struct ib_uverbs_alloc_pd {
 	__aligned_u64 response;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_alloc_pd_resp {
 	__u32 pd_handle;
-	__u32 driver_data[0];
+	__u32 driver_data[];
 };
 
 struct ib_uverbs_dealloc_pd {
@@ -324,12 +324,12 @@ struct ib_uverbs_open_xrcd {
 	__aligned_u64 response;
 	__u32 fd;
 	__u32 oflags;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_open_xrcd_resp {
 	__u32 xrcd_handle;
-	__u32 driver_data[0];
+	__u32 driver_data[];
 };
 
 struct ib_uverbs_close_xrcd {
@@ -343,14 +343,14 @@ struct ib_uverbs_reg_mr {
 	__aligned_u64 hca_va;
 	__u32 pd_handle;
 	__u32 access_flags;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_reg_mr_resp {
 	__u32 mr_handle;
 	__u32 lkey;
 	__u32 rkey;
-	__u32 driver_data[0];
+	__u32 driver_data[];
 };
 
 struct ib_uverbs_rereg_mr {
@@ -362,13 +362,13 @@ struct ib_uverbs_rereg_mr {
 	__aligned_u64 hca_va;
 	__u32 pd_handle;
 	__u32 access_flags;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_rereg_mr_resp {
 	__u32 lkey;
 	__u32 rkey;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_dereg_mr {
@@ -380,13 +380,13 @@ struct ib_uverbs_alloc_mw {
 	__u32 pd_handle;
 	__u8  mw_type;
 	__u8  reserved[3];
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_alloc_mw_resp {
 	__u32 mw_handle;
 	__u32 rkey;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_dealloc_mw {
@@ -408,7 +408,7 @@ struct ib_uverbs_create_cq {
 	__u32 comp_vector;
 	__s32 comp_channel;
 	__u32 reserved;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 enum ib_uverbs_ex_create_cq_flags {
@@ -442,13 +442,13 @@ struct ib_uverbs_resize_cq {
 	__aligned_u64 response;
 	__u32 cq_handle;
 	__u32 cqe;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_resize_cq_resp {
 	__u32 cqe;
 	__u32 reserved;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_poll_cq {
@@ -492,7 +492,7 @@ struct ib_uverbs_wc {
 struct ib_uverbs_poll_cq_resp {
 	__u32 count;
 	__u32 reserved;
-	struct ib_uverbs_wc wc[0];
+	struct ib_uverbs_wc wc[];
 };
 
 struct ib_uverbs_req_notify_cq {
@@ -585,7 +585,7 @@ struct ib_uverbs_create_qp {
 	__u8  qp_type;
 	__u8  is_srq;
 	__u8  reserved;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 enum ib_uverbs_create_qp_mask {
@@ -624,7 +624,7 @@ struct ib_uverbs_open_qp {
 	__u32 qpn;
 	__u8  qp_type;
 	__u8  reserved[7];
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 /* also used for open response */
@@ -669,7 +669,7 @@ struct ib_uverbs_query_qp {
 	__aligned_u64 response;
 	__u32 qp_handle;
 	__u32 attr_mask;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_query_qp_resp {
@@ -703,7 +703,7 @@ struct ib_uverbs_query_qp_resp {
 	__u8  alt_timeout;
 	__u8  sq_sig_all;
 	__u8  reserved[5];
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_modify_qp {
@@ -824,7 +824,7 @@ struct ib_uverbs_post_send {
 	__u32 wr_count;
 	__u32 sge_count;
 	__u32 wqe_size;
-	struct ib_uverbs_send_wr send_wr[0];
+	struct ib_uverbs_send_wr send_wr[];
 };
 
 struct ib_uverbs_post_send_resp {
@@ -843,7 +843,7 @@ struct ib_uverbs_post_recv {
 	__u32 wr_count;
 	__u32 sge_count;
 	__u32 wqe_size;
-	struct ib_uverbs_recv_wr recv_wr[0];
+	struct ib_uverbs_recv_wr recv_wr[];
 };
 
 struct ib_uverbs_post_recv_resp {
@@ -856,7 +856,7 @@ struct ib_uverbs_post_srq_recv {
 	__u32 wr_count;
 	__u32 sge_count;
 	__u32 wqe_size;
-	struct ib_uverbs_recv_wr recv[0];
+	struct ib_uverbs_recv_wr recv[];
 };
 
 struct ib_uverbs_post_srq_recv_resp {
@@ -869,12 +869,12 @@ struct ib_uverbs_create_ah {
 	__u32 pd_handle;
 	__u32 reserved;
 	struct ib_uverbs_ah_attr attr;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_create_ah_resp {
 	__u32 ah_handle;
-	__u32 driver_data[0];
+	__u32 driver_data[];
 };
 
 struct ib_uverbs_destroy_ah {
@@ -886,7 +886,7 @@ struct ib_uverbs_attach_mcast {
 	__u32 qp_handle;
 	__u16 mlid;
 	__u16 reserved;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_detach_mcast {
@@ -894,7 +894,7 @@ struct ib_uverbs_detach_mcast {
 	__u32 qp_handle;
 	__u16 mlid;
 	__u16 reserved;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_flow_spec_hdr {
@@ -1135,7 +1135,7 @@ struct ib_uverbs_flow_attr {
 	 * struct ib_flow_spec_xxx
 	 * struct ib_flow_spec_yyy
 	 */
-	struct ib_uverbs_flow_spec_hdr flow_specs[0];
+	struct ib_uverbs_flow_spec_hdr flow_specs[];
 };
 
 struct ib_uverbs_create_flow  {
@@ -1161,7 +1161,7 @@ struct ib_uverbs_create_srq {
 	__u32 max_wr;
 	__u32 max_sge;
 	__u32 srq_limit;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_create_xsrq {
@@ -1175,7 +1175,7 @@ struct ib_uverbs_create_xsrq {
 	__u32 max_num_tags;
 	__u32 xrcd_handle;
 	__u32 cq_handle;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_create_srq_resp {
@@ -1183,7 +1183,7 @@ struct ib_uverbs_create_srq_resp {
 	__u32 max_wr;
 	__u32 max_sge;
 	__u32 srqn;
-	__u32 driver_data[0];
+	__u32 driver_data[];
 };
 
 struct ib_uverbs_modify_srq {
@@ -1191,14 +1191,14 @@ struct ib_uverbs_modify_srq {
 	__u32 attr_mask;
 	__u32 max_wr;
 	__u32 srq_limit;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_query_srq {
 	__aligned_u64 response;
 	__u32 srq_handle;
 	__u32 reserved;
-	__aligned_u64 driver_data[0];
+	__aligned_u64 driver_data[];
 };
 
 struct ib_uverbs_query_srq_resp {
@@ -1269,7 +1269,7 @@ struct ib_uverbs_ex_create_rwq_ind_table  {
 	 * wq_handle1
 	 * wq_handle2
 	 */
-	__u32 wq_handles[0];
+	__u32 wq_handles[];
 };
 
 struct ib_uverbs_ex_create_rwq_ind_table_resp {
diff --git a/include/uapi/rdma/rdma_user_cm.h b/include/uapi/rdma/rdma_user_cm.h
index ed5a514305c1..7cea03581f79 100644
--- a/include/uapi/rdma/rdma_user_cm.h
+++ b/include/uapi/rdma/rdma_user_cm.h
@@ -184,7 +184,7 @@ struct rdma_ucm_query_addr_resp {
 struct rdma_ucm_query_path_resp {
 	__u32 num_paths;
 	__u32 reserved;
-	struct ib_path_rec_data path_data[0];
+	struct ib_path_rec_data path_data[];
 };
 
 struct rdma_ucm_conn_param {
diff --git a/include/uapi/rdma/rdma_user_ioctl_cmds.h b/include/uapi/rdma/rdma_user_ioctl_cmds.h
index 38ab7accb7be..ab1aef17feb1 100644
--- a/include/uapi/rdma/rdma_user_ioctl_cmds.h
+++ b/include/uapi/rdma/rdma_user_ioctl_cmds.h
@@ -81,7 +81,7 @@ struct ib_uverbs_ioctl_hdr {
 	__aligned_u64 reserved1;
 	__u32 driver_id;
 	__u32 reserved2;
-	struct ib_uverbs_attr  attrs[0];
+	struct ib_uverbs_attr  attrs[];
 };
 
 #endif