From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gustavo A. R. Silva" Subject: [PATCH] dmaengine: qcom: bam_dma: use struct_size() in kzalloc() Date: Fri, 4 Jan 2019 11:32:15 -0600 Message-ID: <20190104173215.GA29029@embeddedor> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: Andy Gross , David Brown , Dan Williams , Vinod Koul Cc: linux-arm-msm@vger.kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, "Gustavo A. R. Silva" List-Id: linux-arm-msm@vger.kernel.org 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 = kzalloc(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 = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva --- drivers/dma/qcom/bam_dma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c index 1617715aa6e0..cb860cb53c27 100644 --- a/drivers/dma/qcom/bam_dma.c +++ b/drivers/dma/qcom/bam_dma.c @@ -636,8 +636,8 @@ static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan, num_alloc += DIV_ROUND_UP(sg_dma_len(sg), BAM_FIFO_SIZE); /* allocate enough room to accomodate the number of entries */ - async_desc = kzalloc(sizeof(*async_desc) + - (num_alloc * sizeof(struct bam_desc_hw)), GFP_NOWAIT); + async_desc = kzalloc(struct_size(async_desc, desc, num_alloc), + GFP_NOWAIT); if (!async_desc) goto err_out; -- 2.20.1