| Message ID | 20190104173215.GA29029@embeddedor (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | dmaengine: qcom: bam_dma: use struct_size() in kzalloc() | expand |
On 04-01-19, 11:32, Gustavo A. R. Silva wrote: > 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. Applied, thanks
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;
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 <gustavo@embeddedor.com> --- drivers/dma/qcom/bam_dma.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)