Commit a665aca8 authored by Jason Gunthorpe's avatar Jason Gunthorpe
Browse files

RDMA/umem: Split ib_umem_num_pages() into ib_umem_num_dma_blocks() 

ib_umem_num_pages() should only be used by things working with the SGL in
CPU pages directly.

Drivers building DMA lists should use the new ib_num_dma_blocks() which
returns the number of blocks rdma_umem_for_each_block() will return.

To make this general for DMA drivers requires a different implementation.
Computing DMA block count based on umem->address only works if the
requested page size is < PAGE_SIZE and/or the IOVA == umem->address.

Instead the number of DMA pages should be computed in the IOVA address
space, not umem->address. Thus the IOVA has to be stored inside the umem
so it can be used for these calculations.

For now set it to umem->address by default and fix it up if
ib_umem_find_best_pgsz() was called. This allows drivers to be converted
to ib_umem_num_dma_blocks() safely.

Link: https://lore.kernel.org/r/6-v2-270386b7e60b+28f4-umem_1_jgg@nvidia.com


Signed-off-by: default avatarJason Gunthorpe <jgg@nvidia.com>
parent 89603f7e

drivers/infiniband/core/umem.c

+6 −1
Original line number Diff line number Diff line
@@ -161,7 +161,7 @@ unsigned long ib_umem_find_best_pgsz(struct ib_umem *umem, 
	if (WARN_ON(!(pgsz_bitmap & GENMASK(PAGE_SHIFT, 0))))

		return 0;



	va = virt;

	umem->iova = va = virt;

	/* The best result is the smallest page size that results in the minimum

	 * number of required pages. Compute the largest page size that could

	 * work based on VA address bits that don't change.
@@ -240,6 +240,11 @@ struct ib_umem *ib_umem_get(struct ib_device *device, unsigned long addr, 
	umem->ibdev      = device;

	umem->length     = size;

	umem->address    = addr;

	/*

	 * Drivers should call ib_umem_find_best_pgsz() to set the iova

	 * correctly.

	 */

	umem->iova = addr;

	umem->writable   = ib_access_writable(access);

	umem->owning_mm = mm = current->mm;

	mmgrab(mm);

drivers/infiniband/hw/cxgb4/mem.c

+1 −1
Original line number Diff line number Diff line
@@ -548,7 +548,7 @@ struct ib_mr *c4iw_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, 


	shift = PAGE_SHIFT;



	n = ib_umem_num_pages(mhp->umem);

	n = ib_umem_num_dma_blocks(mhp->umem, 1 << shift);

	err = alloc_pbl(mhp, n);

	if (err)

		goto err_umem_release;

drivers/infiniband/hw/mlx5/mem.c

+2 −2
Original line number Diff line number Diff line
@@ -169,8 +169,8 @@ void mlx5_ib_populate_pas(struct mlx5_ib_dev *dev, struct ib_umem *umem, 
			  int page_shift, __be64 *pas, int access_flags)

{

	return __mlx5_ib_populate_pas(dev, umem, page_shift, 0,

				      ib_umem_num_pages(umem), pas,

				      access_flags);

				      ib_umem_num_dma_blocks(umem, PAGE_SIZE),

				      pas, access_flags);

}

int mlx5_ib_get_buf_offset(u64 addr, int page_shift, u32 *offset)

{

drivers/infiniband/hw/mthca/mthca_provider.c

+1 −1
Original line number Diff line number Diff line
@@ -881,7 +881,7 @@ static struct ib_mr *mthca_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, 
		goto err;

	}



	n = ib_umem_num_pages(mr->umem);

	n = ib_umem_num_dma_blocks(mr->umem, PAGE_SIZE);



	mr->mtt = mthca_alloc_mtt(dev, n);

	if (IS_ERR(mr->mtt)) {

drivers/infiniband/hw/vmw_pvrdma/pvrdma_mr.c

+1 −1
Original line number Diff line number Diff line
@@ -133,7 +133,7 @@ struct ib_mr *pvrdma_reg_user_mr(struct ib_pd *pd, u64 start, u64 length, 
		return ERR_CAST(umem);

	}



	npages = ib_umem_num_pages(umem);

	npages = ib_umem_num_dma_blocks(umem, PAGE_SIZE);

	if (npages < 0 || npages > PVRDMA_PAGE_DIR_MAX_PAGES) {

		dev_warn(&dev->pdev->dev, "overflow %d pages in mem region\n",

			 npages);