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R. Silva" To: Tudor Ambarus , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Joel Stanley , Andrew Jeffery Subject: [PATCH][next] mtd: spi-nor: controllers: aspeed-smc: Replace zero-length array with flexible-array member Message-ID: <20200319224326.GA25390@embeddedor.com> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - gator4166.hostgator.com X-AntiAbuse: Original Domain - lists.ozlabs.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - embeddedor.com X-BWhitelist: no X-Source-IP: 189.218.116.241 X-Source-L: No X-Exim-ID: 1jF3sw-002DJd-HZ X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cablelink-189-218-116-241.hosts.intercable.net (embeddedor) [189.218.116.241]:53958 X-Source-Auth: gustavo@embeddedor.com X-Email-Count: 38 X-Source-Cap: Z3V6aWRpbmU7Z3V6aWRpbmU7Z2F0b3I0MTY2Lmhvc3RnYXRvci5jb20= X-Local-Domain: yes X-Mailman-Approved-At: Thu, 02 Apr 2020 08:57:25 +1100 X-BeenThere: linux-aspeed@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux ASPEED SoC development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Gustavo A. R. Silva" , linux-mtd@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Errors-To: linux-aspeed-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linux-aspeed" 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 --- 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 */ }; /*