From 5febf6d6ae4d488a5dc388c46d96c17f9556238f Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Mon, 24 Feb 2020 10:14:06 -0600 Subject: scsi: 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/20200224161406.GA21454@embeddedor Reviewed-by: Lee Duncan Reviewed-by: Satish Kharat Signed-off-by: Gustavo A. R. Silva Signed-off-by: Martin K. Petersen --- include/scsi/srp.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'include/scsi/srp.h') diff --git a/include/scsi/srp.h b/include/scsi/srp.h index 9220758d5087..177d8026e96f 100644 --- a/include/scsi/srp.h +++ b/include/scsi/srp.h @@ -109,7 +109,7 @@ struct srp_direct_buf { struct srp_indirect_buf { struct srp_direct_buf table_desc; __be32 len; - struct srp_direct_buf desc_list[0]; + struct srp_direct_buf desc_list[]; } __attribute__((packed)); /* Immediate data buffer descriptor as defined in SRP2. */ @@ -244,7 +244,7 @@ struct srp_cmd { u8 reserved4; u8 add_cdb_len; u8 cdb[16]; - u8 add_data[0]; + u8 add_data[]; }; enum { @@ -274,7 +274,7 @@ struct srp_rsp { __be32 data_in_res_cnt; __be32 sense_data_len; __be32 resp_data_len; - u8 data[0]; + u8 data[]; } __attribute__((packed)); struct srp_cred_req { @@ -306,7 +306,7 @@ struct srp_aer_req { struct scsi_lun lun; __be32 sense_data_len; u32 reserved3; - u8 sense_data[0]; + u8 sense_data[]; } __attribute__((packed)); struct srp_aer_rsp { -- cgit v1.2.3-59-g8ed1b