From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Thu, 19 Mar 2020 17:43:26 -0500
Subject: mtd: spi-nor: controllers: aspeed-smc: Replace zero-length array with
flexible-array member
Git-commit: 5bb783cc92f0da8c36c8cc288d586a4ceb6c742a
Patch-mainline: v5.7-rc1
References: jsc#SLE-14214 jsc#SLE-16606
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 <gustavo@embeddedor.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Matthias Brugger <mbrugger@suse.com>
---
drivers/mtd/spi-nor/controllers/aspeed-smc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mtd/spi-nor/controllers/aspeed-smc.c b/drivers/mtd/spi-nor/controllers/aspeed-smc.c
index 395127349aa8..e26a1897db0e 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 */
};
/*
--
2.28.0