linux-kernel - [PATCH] ioat/dca: Use struct

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Message-ID: <20190828184015.GA4273@embeddedor>
Date:   Wed, 28 Aug 2019 13:40:15 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     Vinod Koul <vkoul@...nel.org>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
        "Gustavo A. R. Silva" <gustavo@...eddedor.com>
Subject: [PATCH] ioat/dca: Use struct_size() helper

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 ioat_dca_priv {
	...
        struct ioat_dca_slot     req_slots[0];
};

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(*ioatdca) + (sizeof(struct ioat_dca_slot) * slots)

with:

struct_size(ioatdca, req_slots, slots)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@...eddedor.com>
---
 drivers/dma/ioat/dca.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/dma/ioat/dca.c b/drivers/dma/ioat/dca.c
index 70fd8454d002..be61c32a876f 100644
--- a/drivers/dma/ioat/dca.c
+++ b/drivers/dma/ioat/dca.c
@@ -286,8 +286,7 @@ struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
 		return NULL;
 
 	dca = alloc_dca_provider(&ioat_dca_ops,
-				 sizeof(*ioatdca)
-				      + (sizeof(struct ioat_dca_slot) * slots));
+				 struct_size(ioatdca, req_slots, slots));
 	if (!dca)
 		return NULL;
 
-- 
2.23.0