From 5b361328ca649534d721e4eae20c96ccbe702ce7 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 12 Feb 2020 19:04:25 -0600 Subject: RDMA: Replace zero-length array with flexible-array member The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Link: https://lore.kernel.org/r/20200213010425.GA13068@embeddedor.com Signed-off-by: Gustavo A. R. Silva Signed-off-by: Jason Gunthorpe # added a few more --- include/rdma/ib_fmr_pool.h | 2 +- include/rdma/ib_verbs.h | 18 +++++++++--------- include/rdma/opa_vnic.h | 2 +- include/rdma/rdmavt_mr.h | 2 +- include/rdma/rdmavt_qp.h | 2 +- 5 files changed, 13 insertions(+), 13 deletions(-) (limited to 'include/rdma') diff --git a/include/rdma/ib_fmr_pool.h b/include/rdma/ib_fmr_pool.h index f8982e4e9702..2fd9bfb6d648 100644 --- a/include/rdma/ib_fmr_pool.h +++ b/include/rdma/ib_fmr_pool.h @@ -73,7 +73,7 @@ struct ib_pool_fmr { int remap_count; u64 io_virtual_address; int page_list_len; - u64 page_list[0]; + u64 page_list[]; }; struct ib_fmr_pool *ib_create_fmr_pool(struct ib_pd *pd, diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index 5f3a04ead9f5..bbc5cfb57cd2 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -1876,7 +1876,7 @@ struct ib_flow_eth_filter { __be16 ether_type; __be16 vlan_tag; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_eth { @@ -1890,7 +1890,7 @@ struct ib_flow_ib_filter { __be16 dlid; __u8 sl; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_ib { @@ -1915,7 +1915,7 @@ struct ib_flow_ipv4_filter { u8 ttl; u8 flags; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_ipv4 { @@ -1933,7 +1933,7 @@ struct ib_flow_ipv6_filter { u8 traffic_class; u8 hop_limit; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_ipv6 { @@ -1947,7 +1947,7 @@ struct ib_flow_tcp_udp_filter { __be16 dst_port; __be16 src_port; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_tcp_udp { @@ -1959,7 +1959,7 @@ struct ib_flow_spec_tcp_udp { struct ib_flow_tunnel_filter { __be32 tunnel_id; - u8 real_sz[0]; + u8 real_sz[]; }; /* ib_flow_spec_tunnel describes the Vxlan tunnel @@ -1976,7 +1976,7 @@ struct ib_flow_esp_filter { __be32 spi; __be32 seq; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_esp { @@ -1991,7 +1991,7 @@ struct ib_flow_gre_filter { __be16 protocol; __be32 key; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_gre { @@ -2004,7 +2004,7 @@ struct ib_flow_spec_gre { struct ib_flow_mpls_filter { __be32 tag; /* Must be last */ - u8 real_sz[0]; + u8 real_sz[]; }; struct ib_flow_spec_mpls { diff --git a/include/rdma/opa_vnic.h b/include/rdma/opa_vnic.h index 0c07a70bd7f6..e90b149fe92a 100644 --- a/include/rdma/opa_vnic.h +++ b/include/rdma/opa_vnic.h @@ -75,7 +75,7 @@ struct opa_vnic_rdma_netdev { struct rdma_netdev rn; /* keep this first */ /* followed by device private data */ - char *dev_priv[0]; + char *dev_priv[]; }; static inline void *opa_vnic_priv(const struct net_device *dev) diff --git a/include/rdma/rdmavt_mr.h b/include/rdma/rdmavt_mr.h index 72a3856d4057..ce6c888f7fe7 100644 --- a/include/rdma/rdmavt_mr.h +++ b/include/rdma/rdmavt_mr.h @@ -85,7 +85,7 @@ struct rvt_mregion { u8 lkey_published; /* in global table */ struct percpu_ref refcount; struct completion comp; /* complete when refcount goes to zero */ - struct rvt_segarray *map[0]; /* the segments */ + struct rvt_segarray *map[]; /* the segments */ }; #define RVT_MAX_LKEY_TABLE_BITS 23 diff --git a/include/rdma/rdmavt_qp.h b/include/rdma/rdmavt_qp.h index 0d5c70e2d8ab..5fc10108703a 100644 --- a/include/rdma/rdmavt_qp.h +++ b/include/rdma/rdmavt_qp.h @@ -191,7 +191,7 @@ struct rvt_swqe { u32 ssn; /* send sequence number */ u32 length; /* total length of data in sg_list */ void *priv; /* driver dependent field */ - struct rvt_sge sg_list[0]; + struct rvt_sge sg_list[]; }; /** -- cgit v1.2.3