From: Gustavo A. R. Silva Date: Thu, 19 Mar 2020 22:43:26 +0000 (-0500) Subject: mtd: spi-nor: controllers: aspeed-smc: Replace zero-length array with flexible-array... X-Git-Tag: v5.7-rc1~113^2~2^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5bb783cc92f0da8c36c8cc288d586a4ceb6c742a;p=thirdparty%2Fkernel%2Flinux.git mtd: spi-nor: controllers: aspeed-smc: 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") Signed-off-by: Gustavo A. R. Silva Signed-off-by: Tudor Ambarus --- diff --git a/drivers/mtd/spi-nor/controllers/aspeed-smc.c b/drivers/mtd/spi-nor/controllers/aspeed-smc.c index 395127349aa8d..e26a1897db0e0 100644 --- a/drivers/mtd/spi-nor/controllers/aspeed-smc.c +++ b/drivers/mtd/spi-nor/controllers/aspeed-smc.c @@ -109,7 +109,7 @@ struct aspeed_smc_controller { void __iomem *ahb_base; /* per-chip windows resource */ u32 ahb_window_size; /* full mapping window size */ - struct aspeed_smc_chip *chips[0]; /* pointers to attached chips */ + struct aspeed_smc_chip *chips[]; /* pointers to attached chips */ }; /*