From 94dfc73e7cf4a31da66b8843f0b9283ddd6b8381 Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 6 Apr 2022 19:36:51 -0500 Subject: treewide: uapi: Replace zero-length arrays with flexible-array members MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Link: https://lore.kernel.org/lkml/62b675ec.wKX6AOZ6cbE71vtF%25lkp@intel.com/ Acked-by: Dan Williams # For ndctl.h Signed-off-by: Gustavo A. R. Silva --- include/uapi/linux/ndctl.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'include/uapi/linux/ndctl.h') diff --git a/include/uapi/linux/ndctl.h b/include/uapi/linux/ndctl.h index 17e02b64ea2e..73516e263627 100644 --- a/include/uapi/linux/ndctl.h +++ b/include/uapi/linux/ndctl.h @@ -30,25 +30,25 @@ struct nd_cmd_get_config_data_hdr { __u32 in_offset; __u32 in_length; __u32 status; - __u8 out_buf[0]; + __u8 out_buf[]; } __packed; struct nd_cmd_set_config_hdr { __u32 in_offset; __u32 in_length; - __u8 in_buf[0]; + __u8 in_buf[]; } __packed; struct nd_cmd_vendor_hdr { __u32 opcode; __u32 in_length; - __u8 in_buf[0]; + __u8 in_buf[]; } __packed; struct nd_cmd_vendor_tail { __u32 status; __u32 out_length; - __u8 out_buf[0]; + __u8 out_buf[]; } __packed; struct nd_cmd_ars_cap { @@ -86,7 +86,7 @@ struct nd_cmd_ars_status { __u32 reserved; __u64 err_address; __u64 length; - } __packed records[0]; + } __packed records[]; } __packed; struct nd_cmd_clear_error { -- cgit v1.2.3