On Tue, Mar 12, 2024 at 12:53:05PM +0200, Leon Romanovsky wrote: > On Mon, Mar 11, 2024 at 07:38:21PM +0800, Boshi Yu wrote: > > From: Boshi Yu <boshiyu@xxxxxxxxxxxxxxxxx> > > > > The dma_alloc_coherent() interface automatically zero the memory returned. > > Can you please point to the DMA code which does that? We have noticed a patchset which ensures that dma_alloc_coherent() always returns zeroed memory. The url of this patchset is listed as below: https://lore.kernel.org/all/20181214082515.14835-1-hch@xxxxxx/T/#m70c723c646004445713f31b7837f7e9d910c06f5 Besides, you may refer to commit 518a2f1925c3 ("dma-mapping: zero memory returned from dma_alloc_*") for details. This commit zeros memory by passing __GFP_ZERO flag or calling memset internally. For example, the dma_alloc_direct() interface calls memset() to zero the allocated memory. Thanks, Boshi Yu > > > Thus, we do not need to specify the __GFP_ZERO flag explicitly when we call > > dma_alloc_coherent(). > > > > Reviewed-by: Cheng Xu <chengyou@xxxxxxxxxxxxxxxxx> > > Signed-off-by: Boshi Yu <boshiyu@xxxxxxxxxxxxxxxxx> > > --- > > drivers/infiniband/hw/erdma/erdma_cmdq.c | 6 ++---- > > drivers/infiniband/hw/erdma/erdma_eq.c | 6 ++---- > > 2 files changed, 4 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/infiniband/hw/erdma/erdma_cmdq.c b/drivers/infiniband/hw/erdma/erdma_cmdq.c > > index 0ac2683cfccf..43ff40b5a09d 100644 > > --- a/drivers/infiniband/hw/erdma/erdma_cmdq.c > > +++ b/drivers/infiniband/hw/erdma/erdma_cmdq.c > > @@ -127,8 +127,7 @@ static int erdma_cmdq_cq_init(struct erdma_dev *dev) > > > > cq->depth = cmdq->sq.depth; > > cq->qbuf = dma_alloc_coherent(&dev->pdev->dev, cq->depth << CQE_SHIFT, > > - &cq->qbuf_dma_addr, > > - GFP_KERNEL | __GFP_ZERO); > > + &cq->qbuf_dma_addr, GFP_KERNEL); > > if (!cq->qbuf) > > return -ENOMEM; > > > > @@ -162,8 +161,7 @@ static int erdma_cmdq_eq_init(struct erdma_dev *dev) > > > > eq->depth = cmdq->max_outstandings; > > eq->qbuf = dma_alloc_coherent(&dev->pdev->dev, eq->depth << EQE_SHIFT, > > - &eq->qbuf_dma_addr, > > - GFP_KERNEL | __GFP_ZERO); > > + &eq->qbuf_dma_addr, GFP_KERNEL); > > if (!eq->qbuf) > > return -ENOMEM; > > > > diff --git a/drivers/infiniband/hw/erdma/erdma_eq.c b/drivers/infiniband/hw/erdma/erdma_eq.c > > index 0a4746e6d05c..84ccdd8144c9 100644 > > --- a/drivers/infiniband/hw/erdma/erdma_eq.c > > +++ b/drivers/infiniband/hw/erdma/erdma_eq.c > > @@ -87,8 +87,7 @@ int erdma_aeq_init(struct erdma_dev *dev) > > eq->depth = ERDMA_DEFAULT_EQ_DEPTH; > > > > eq->qbuf = dma_alloc_coherent(&dev->pdev->dev, eq->depth << EQE_SHIFT, > > - &eq->qbuf_dma_addr, > > - GFP_KERNEL | __GFP_ZERO); > > + &eq->qbuf_dma_addr, GFP_KERNEL); > > if (!eq->qbuf) > > return -ENOMEM; > > > > @@ -237,8 +236,7 @@ static int erdma_ceq_init_one(struct erdma_dev *dev, u16 ceqn) > > > > eq->depth = ERDMA_DEFAULT_EQ_DEPTH; > > eq->qbuf = dma_alloc_coherent(&dev->pdev->dev, eq->depth << EQE_SHIFT, > > - &eq->qbuf_dma_addr, > > - GFP_KERNEL | __GFP_ZERO); > > + &eq->qbuf_dma_addr, GFP_KERNEL); > > if (!eq->qbuf) > > return -ENOMEM; > > > > -- > > 2.39.3 > > > >
