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

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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: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Jason Gunthorpe 2020-09-04 19:41:47 -03:00
parent 89603f7e7e
commit a665aca89a
6 changed files with 23 additions and 9 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

7
drivers/infiniband/core/umem.c
View file

@ -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);

2
drivers/infiniband/hw/cxgb4/mem.c
View file

@ -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;

4
drivers/infiniband/hw/mlx5/mem.c
View file

@ -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)
{

2
drivers/infiniband/hw/mthca/mthca_provider.c
View file

@ -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)) {

2
drivers/infiniband/hw/vmw_pvrdma/pvrdma_mr.c
View file

@ -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);

15
include/rdma/ib_umem.h
View file

@ -17,6 +17,7 @@ struct ib_umem_odp;
struct ib_umem {
struct ib_device *ibdev;
struct mm_struct *owning_mm;
u64 iova;
size_t length;
unsigned long address;
u32 writable : 1;
@ -33,11 +34,17 @@ static inline int ib_umem_offset(struct ib_umem *umem)
return umem->address & ~PAGE_MASK;
}
static inline size_t ib_umem_num_dma_blocks(struct ib_umem *umem,
unsigned long pgsz)
{
return (size_t)((ALIGN(umem->iova + umem->length, pgsz) -
ALIGN_DOWN(umem->iova, pgsz))) /
pgsz;
}
static inline size_t ib_umem_num_pages(struct ib_umem *umem)
{
return (ALIGN(umem->address + umem->length, PAGE_SIZE) -
ALIGN_DOWN(umem->address, PAGE_SIZE)) >>
PAGE_SHIFT;
return ib_umem_num_dma_blocks(umem, PAGE_SIZE);
}
static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,
@ -55,6 +62,8 @@ static inline void __rdma_umem_block_iter_start(struct ib_block_iter *biter,
* pgsz must be <= PAGE_SIZE or computed by ib_umem_find_best_pgsz(). The
* returned DMA blocks will be aligned to pgsz and span the range:
* ALIGN_DOWN(umem->address, pgsz) to ALIGN(umem->address + umem->length, pgsz)
*
* Performs exactly ib_umem_num_dma_blocks() iterations.
*/
#define rdma_umem_for_each_dma_block(umem, biter, pgsz) \
for (__rdma_umem_block_iter_start(biter, umem, pgsz); \