Re: [PATCH for-next] RDMA/cxgb4: use dma_mmap_coherent() for mapping non-contiguous memory

[Zhu Yanjun <yanjun.zhu@xxxxxxxxx>]

在 2024/7/5 21:17, Anumula Murali Mohan Reddy 写道:
> dma_alloc_coherent() allocates contiguous memory irrespective of
> iommu mode, but after commit f5ff79fddf0e ("dma-mapping: remove
> CONFIG_DMA_REMAP") if iommu is enabled in translate mode,

CC linux-mm@xxxxxxxxx

Zhu Yanjun

> dma_alloc_coherent() may allocate non-contiguous memory.
> Attempt to map this memory results in panic.
> This patch fixes the issue by using dma_mmap_coherent() to map each page
> to user space.
>
> Fixes: f5ff79fddf0e ("dma-mapping: remove CONFIG_DMA_REMAP")
> Signed-off-by: Anumula Murali Mohan Reddy <anumula@xxxxxxxxxxx>
> Signed-off-by: Potnuri Bharat Teja <bharat@xxxxxxxxxxx>
> ---
>   drivers/infiniband/hw/cxgb4/cq.c       |  4 +++
>   drivers/infiniband/hw/cxgb4/iw_cxgb4.h |  2 ++
>   drivers/infiniband/hw/cxgb4/provider.c | 48 +++++++++++++++++++++-----
>   drivers/infiniband/hw/cxgb4/qp.c       | 14 ++++++++
>   4 files changed, 59 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/infiniband/hw/cxgb4/cq.c b/drivers/infiniband/hw/cxgb4/cq.c
> index 5111421f9473..81cfc876fa89 100644
> --- a/drivers/infiniband/hw/cxgb4/cq.c
> +++ b/drivers/infiniband/hw/cxgb4/cq.c
> @@ -1127,12 +1127,16 @@ int c4iw_create_cq(struct ib_cq *ibcq, const struct ib_cq_init_attr *attr,
>   
>   		mm->key = uresp.key;
>   		mm->addr = virt_to_phys(chp->cq.queue);
> +		mm->vaddr = chp->cq.queue;
> +		mm->dma_addr = chp->cq.dma_addr;
>   		mm->len = chp->cq.memsize;
>   		insert_mmap(ucontext, mm);
>   
>   		mm2->key = uresp.gts_key;
>   		mm2->addr = chp->cq.bar2_pa;
>   		mm2->len = PAGE_SIZE;
> +		mm2->vaddr = NULL;
> +		mm2->dma_addr = 0;
>   		insert_mmap(ucontext, mm2);
>   	}
>   
> diff --git a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
> index f838bb6718af..5eedc6cf0f8c 100644
> --- a/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
> +++ b/drivers/infiniband/hw/cxgb4/iw_cxgb4.h
> @@ -536,6 +536,8 @@ struct c4iw_mm_entry {
>   	struct list_head entry;
>   	u64 addr;
>   	u32 key;
> +	void *vaddr;
> +	dma_addr_t dma_addr;
>   	unsigned len;
>   };
>   
> diff --git a/drivers/infiniband/hw/cxgb4/provider.c b/drivers/infiniband/hw/cxgb4/provider.c
> index 246b739ddb2b..6227775970c9 100644
> --- a/drivers/infiniband/hw/cxgb4/provider.c
> +++ b/drivers/infiniband/hw/cxgb4/provider.c
> @@ -131,6 +131,10 @@ static int c4iw_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
>   	struct c4iw_mm_entry *mm;
>   	struct c4iw_ucontext *ucontext;
>   	u64 addr;
> +	size_t size;
> +	void *vaddr;
> +	unsigned long vm_pgoff;
> +	dma_addr_t dma_addr;
>   
>   	pr_debug("pgoff 0x%lx key 0x%x len %d\n", vma->vm_pgoff,
>   		 key, len);
> @@ -145,6 +149,9 @@ static int c4iw_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
>   	if (!mm)
>   		return -EINVAL;
>   	addr = mm->addr;
> +	vaddr = mm->vaddr;
> +	dma_addr = mm->dma_addr;
> +	size = mm->len;
>   	kfree(mm);
>   
>   	if ((addr >= pci_resource_start(rdev->lldi.pdev, 0)) &&
> @@ -155,9 +162,17 @@ static int c4iw_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
>   		 * MA_SYNC register...
>   		 */
>   		vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> -		ret = io_remap_pfn_range(vma, vma->vm_start,
> -					 addr >> PAGE_SHIFT,
> -					 len, vma->vm_page_prot);
> +		if (vaddr && is_vmalloc_addr(vaddr)) {
> +			vm_pgoff = vma->vm_pgoff;
> +			vma->vm_pgoff = 0;
> +			ret = dma_mmap_coherent(&rdev->lldi.pdev->dev, vma,
> +						vaddr, dma_addr, size);
> +			vma->vm_pgoff = vm_pgoff;
> +		} else {
> +			ret = io_remap_pfn_range(vma, vma->vm_start,
> +						 addr >> PAGE_SHIFT,
> +						 len, vma->vm_page_prot);
> +		}
>   	} else if ((addr >= pci_resource_start(rdev->lldi.pdev, 2)) &&
>   		   (addr < (pci_resource_start(rdev->lldi.pdev, 2) +
>   		    pci_resource_len(rdev->lldi.pdev, 2)))) {
> @@ -175,17 +190,32 @@ static int c4iw_mmap(struct ib_ucontext *context, struct vm_area_struct *vma)
>   				vma->vm_page_prot =
>   					pgprot_noncached(vma->vm_page_prot);
>   		}
> -		ret = io_remap_pfn_range(vma, vma->vm_start,
> -					 addr >> PAGE_SHIFT,
> -					 len, vma->vm_page_prot);
> +		if (vaddr && is_vmalloc_addr(vaddr)) {
> +			vm_pgoff = vma->vm_pgoff;
> +			vma->vm_pgoff = 0;
> +			ret = dma_mmap_coherent(&rdev->lldi.pdev->dev, vma,
> +						vaddr, dma_addr, size);
> +			vma->vm_pgoff = vm_pgoff;
> +		} else {
> +			ret = io_remap_pfn_range(vma, vma->vm_start,
> +						 addr >> PAGE_SHIFT,
> +						 len, vma->vm_page_prot);
> +		}
>   	} else {
>   
>   		/*
>   		 * Map WQ or CQ contig dma memory...
>   		 */
> -		ret = remap_pfn_range(vma, vma->vm_start,
> -				      addr >> PAGE_SHIFT,
> -				      len, vma->vm_page_prot);
> +		if (vaddr && is_vmalloc_addr(vaddr)) {
> +			vm_pgoff = vma->vm_pgoff;
> +			vma->vm_pgoff = 0;
> +			ret = dma_mmap_coherent(&rdev->lldi.pdev->dev, vma,
> +						vaddr, dma_addr, size);
> +		} else {
> +			ret = remap_pfn_range(vma, vma->vm_start,
> +					      addr >> PAGE_SHIFT,
> +					      len, vma->vm_page_prot);
> +		}
>   	}
>   
>   	return ret;
> diff --git a/drivers/infiniband/hw/cxgb4/qp.c b/drivers/infiniband/hw/cxgb4/qp.c
> index d16d8eaa1415..3f6fb4b34d5a 100644
> --- a/drivers/infiniband/hw/cxgb4/qp.c
> +++ b/drivers/infiniband/hw/cxgb4/qp.c
> @@ -2282,16 +2282,22 @@ int c4iw_create_qp(struct ib_qp *qp, struct ib_qp_init_attr *attrs,
>   			goto err_free_ma_sync_key;
>   		sq_key_mm->key = uresp.sq_key;
>   		sq_key_mm->addr = qhp->wq.sq.phys_addr;
> +		sq_key_mm->vaddr = qhp->wq.sq.queue;
> +		sq_key_mm->dma_addr = qhp->wq.sq.dma_addr;
>   		sq_key_mm->len = PAGE_ALIGN(qhp->wq.sq.memsize);
>   		insert_mmap(ucontext, sq_key_mm);
>   		if (!attrs->srq) {
>   			rq_key_mm->key = uresp.rq_key;
>   			rq_key_mm->addr = virt_to_phys(qhp->wq.rq.queue);
> +			rq_key_mm->vaddr = qhp->wq.rq.queue;
> +			rq_key_mm->dma_addr = qhp->wq.rq.dma_addr;
>   			rq_key_mm->len = PAGE_ALIGN(qhp->wq.rq.memsize);
>   			insert_mmap(ucontext, rq_key_mm);
>   		}
>   		sq_db_key_mm->key = uresp.sq_db_gts_key;
>   		sq_db_key_mm->addr = (u64)(unsigned long)qhp->wq.sq.bar2_pa;
> +		sq_db_key_mm->vaddr = NULL;
> +		sq_db_key_mm->dma_addr = 0;
>   		sq_db_key_mm->len = PAGE_SIZE;
>   		insert_mmap(ucontext, sq_db_key_mm);
>   		if (!attrs->srq) {
> @@ -2299,6 +2305,8 @@ int c4iw_create_qp(struct ib_qp *qp, struct ib_qp_init_attr *attrs,
>   			rq_db_key_mm->addr =
>   				(u64)(unsigned long)qhp->wq.rq.bar2_pa;
>   			rq_db_key_mm->len = PAGE_SIZE;
> +			rq_db_key_mm->vaddr = NULL;
> +			rq_db_key_mm->dma_addr = 0;
>   			insert_mmap(ucontext, rq_db_key_mm);
>   		}
>   		if (ma_sync_key_mm) {
> @@ -2307,6 +2315,8 @@ int c4iw_create_qp(struct ib_qp *qp, struct ib_qp_init_attr *attrs,
>   				(pci_resource_start(rhp->rdev.lldi.pdev, 0) +
>   				PCIE_MA_SYNC_A) & PAGE_MASK;
>   			ma_sync_key_mm->len = PAGE_SIZE;
> +			ma_sync_key_mm->vaddr = NULL;
> +			ma_sync_key_mm->dma_addr = 0;
>   			insert_mmap(ucontext, ma_sync_key_mm);
>   		}
>   
> @@ -2763,10 +2773,14 @@ int c4iw_create_srq(struct ib_srq *ib_srq, struct ib_srq_init_attr *attrs,
>   		srq_key_mm->key = uresp.srq_key;
>   		srq_key_mm->addr = virt_to_phys(srq->wq.queue);
>   		srq_key_mm->len = PAGE_ALIGN(srq->wq.memsize);
> +		srq_key_mm->vaddr = srq->wq.queue;
> +		srq_key_mm->dma_addr = srq->wq.dma_addr;
>   		insert_mmap(ucontext, srq_key_mm);
>   		srq_db_key_mm->key = uresp.srq_db_gts_key;
>   		srq_db_key_mm->addr = (u64)(unsigned long)srq->wq.bar2_pa;
>   		srq_db_key_mm->len = PAGE_SIZE;
> +		srq_db_key_mm->vaddr = NULL;
> +		srq_db_key_mm->dma_addr = 0;
>   		insert_mmap(ucontext, srq_db_key_mm);
>   	}
>