Re: [PATCH 2/7] RDMA/hfi1: don't pass bogus GFP_ flags to dma_alloc_coherent

On 11/13/2022 10:35 AM, Christoph Hellwig wrote:

dma_alloc_coherent is an opaque allocator that only uses the GFP_ flags for allocation context control. Don't pass GFP_USER which doesn't make sense for a kernel DMA allocation or __GFP_COMP which makes no sense for an allocation that can't in any way be converted to a page pointer.

Signed-off-by: Christoph Hellwig hch@lst.de

drivers/infiniband/hw/hfi1/init.c | 21 +++------------------ 1 file changed, 3 insertions(+), 18 deletions(-)

diff --git a/drivers/infiniband/hw/hfi1/init.c b/drivers/infiniband/hw/hfi1/init.c index 436372b314312..24c0f0d257fc9 100644 --- a/drivers/infiniband/hw/hfi1/init.c +++ b/drivers/infiniband/hw/hfi1/init.c @@ -1761,17 +1761,11 @@ int hfi1_create_rcvhdrq(struct hfi1_devdata *dd, struct hfi1_ctxtdata *rcd) unsigned amt;

  if (!rcd->rcvhdrq) {

•         gfp_t gfp_flags;
  

•         amt = rcvhdrq_size(rcd);
  
  

•         if (rcd->ctxt < dd->first_dyn_alloc_ctxt || rcd->is_vnic)
  

•                 gfp_flags = GFP_KERNEL;
  

•         else
  

•                 gfp_flags = GFP_USER;
          rcd->rcvhdrq = dma_alloc_coherent(&dd->pcidev->dev, amt,
                                            &rcd->rcvhdrq_dma,
  

•                                           gfp_flags | __GFP_COMP);
  

•                                           GFP_KERNEL);
  

A user context receive header queue may be mapped into user space. Is that not the use case for GFP_USER? The above conditional is what decides.

Why do you think GFP_USER should be removed here?

-Dean External recipient