From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gateway21.websitewelcome.com ([192.185.45.163]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1ggtQH-0001ws-V7 for linux-mtd@lists.infradead.org; Tue, 08 Jan 2019 15:36:11 +0000 Received: from cm12.websitewelcome.com (cm12.websitewelcome.com [100.42.49.8]) by gateway21.websitewelcome.com (Postfix) with ESMTP id 29471400C7430 for ; Tue, 8 Jan 2019 09:36:08 -0600 (CST) Date: Tue, 8 Jan 2019 09:36:01 -0600 From: "Gustavo A. R. Silva" To: David Woodhouse , Brian Norris , Boris Brezillon , Marek Vasut , Richard Weinberger Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" Subject: [PATCH] mtd: gen_probe: Use struct_size() in kmalloc() Message-ID: <20190108153601.GA11557@embeddedor> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct foo { int stuff; void *entry[]; }; instance = kmalloc(sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = kmalloc(struct_size(instance, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- drivers/mtd/chips/gen_probe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/mtd/chips/gen_probe.c b/drivers/mtd/chips/gen_probe.c index 837b04ab96a9..839ed40625d6 100644 --- a/drivers/mtd/chips/gen_probe.c +++ b/drivers/mtd/chips/gen_probe.c @@ -135,7 +135,7 @@ static struct cfi_private *genprobe_ident_chips(struct map_info *map, struct chi * our caller, and copy the appropriate data into them. */ - retcfi = kmalloc(sizeof(struct cfi_private) + cfi.numchips * sizeof(struct flchip), GFP_KERNEL); + retcfi = kmalloc(struct_size(retcfi, chips, cfi.numchips), GFP_KERNEL); if (!retcfi) { kfree(cfi.cfiq); -- 2.20.1