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 --- drivers/scsi/mvsas/mv_sas.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/scsi/mvsas') diff --git a/drivers/scsi/mvsas/mv_sas.h b/drivers/scsi/mvsas/mv_sas.h index 519edc796691..327fdd5ee962 100644 --- a/drivers/scsi/mvsas/mv_sas.h +++ b/drivers/scsi/mvsas/mv_sas.h @@ -394,7 +394,7 @@ struct mvs_info { dma_addr_t bulk_buffer_dma1; #define TRASH_BUCKET_SIZE 0x20000 void *dma_pool; - struct mvs_slot_info slot_info[0]; + struct mvs_slot_info slot_info[]; }; struct mvs_prv_info{ -- cgit v1.2.3