[PATCH v10 13/24] RDMA/core: Convert UMEM ODP DMA mapping to caching IOVA and page linkage

Leon Romanovsky
2025-04-28T09:23:36Z

From: Leon Romanovsky <leonro@nvidia.com>

Reuse newly added DMA API to cache IOVA and only link/unlink pages
in fast path for UMEM ODP flow.

Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
drivers/infiniband/core/umem_odp.c | 106 ++++++---------------------
drivers/infiniband/hw/mlx5/mlx5_ib.h | 11 ++-
drivers/infiniband/hw/mlx5/odp.c | 40 ++++++----
drivers/infiniband/hw/mlx5/umr.c | 12 ++-
drivers/infiniband/sw/rxe/rxe_odp.c | 4 +-
include/rdma/ib_umem_odp.h | 13 +---
6 files changed, 71 insertions(+), 115 deletions(-)

diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index 2a061f377eb1..30cd8f353476 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -41,6 +41,7 @@
#include <linux/hugetlb.h>
#include <linux/interval_tree.h>
#include <linux/hmm.h>
+#include <linux/hmm-dma.h>
#include <linux/pagemap.h>

#include <rdma/ib_umem_odp.h>
@@ -50,6 +51,7 @@
static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
const struct mmu_interval_notifier_ops *ops)
{
+ struct ib_device *dev = umem_odp->umem.ibdev;
int ret;

umem_odp->umem.is_odp = 1;
@@ -59,7 +61,6 @@ static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
size_t page_size = 1UL << umem_odp->page_shift;
unsigned long start;
unsigned long end;
- size_t ndmas, npfns;

start = ALIGN_DOWN(umem_odp->umem.address, page_size);
if (check_add_overflow(umem_odp->umem.address,
@@ -70,38 +71,23 @@ static inline int ib_init_umem_odp(struct ib_umem_odp *umem_odp,
if (unlikely(end < page_size))
return -EOVERFLOW;

- ndmas = (end - start) >> umem_odp->page_shift;
- if (!ndmas)
- return -EINVAL;
-
- npfns = (end - start) >> PAGE_SHIFT;
- umem_odp->pfn_list = kvcalloc(
- npfns, sizeof(*umem_odp->pfn_list),
- GFP_KERNEL | __GFP_NOWARN);
- if (!umem_odp->pfn_list)
- return -ENOMEM;
-
- umem_odp->dma_list = kvcalloc(
- ndmas, sizeof(*umem_odp->dma_list),
- GFP_KERNEL | __GFP_NOWARN);
- if (!umem_odp->dma_list) {
- ret = -ENOMEM;
- goto out_pfn_list;
- }
+ ret = hmm_dma_map_alloc(dev->dma_device, &umem_odp->map,
+ (end - start) >> PAGE_SHIFT,
+ 1 << umem_odp->page_shift);
+ if (ret)
+ return ret;

ret = mmu_interval_notifier_insert(&umem_odp->notifier,
umem_odp->umem.owning_mm,
start, end - start, ops);
if (ret)
- goto out_dma_list;
+ goto out_free_map;
}

return 0;

-out_dma_list:
- kvfree(umem_odp->dma_list);
-out_pfn_list:
- kvfree(umem_odp->pfn_list);
+out_free_map:
+ hmm_dma_map_free(dev->dma_device, &umem_odp->map);
return ret;
}

@@ -264,6 +250,8 @@ EXPORT_SYMBOL(ib_umem_odp_get);

void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
{
+ struct ib_device *dev = umem_odp->umem.ibdev;
+
/*
* Ensure that no more pages are mapped in the umem.
*
@@ -276,48 +264,17 @@ void ib_umem_odp_release(struct ib_umem_odp *umem_odp)
ib_umem_end(umem_odp));
mutex_unlock(&umem_odp->umem_mutex);
mmu_interval_notifier_remove(&umem_odp->notifier);
- kvfree(umem_odp->dma_list);
- kvfree(umem_odp->pfn_list);
+ hmm_dma_map_free(dev->dma_device, &umem_odp->map);
}
put_pid(umem_odp->tgid);
kfree(umem_odp);
}
EXPORT_SYMBOL(ib_umem_odp_release);

-/*
- * Map for DMA and insert a single page into the on-demand paging page tables.
- *
- * @umem: the umem to insert the page to.
- * @dma_index: index in the umem to add the dma to.
- * @page: the page struct to map and add.
- * @access_mask: access permissions needed for this page.
- *
- * The function returns -EFAULT if the DMA mapping operation fails.
- *
- */
-static int ib_umem_odp_map_dma_single_page(
- struct ib_umem_odp *umem_odp,
- unsigned int dma_index,
- struct page *page)
-{
- struct ib_device *dev = umem_odp->umem.ibdev;
- dma_addr_t *dma_addr = &umem_odp->dma_list[dma_index];
-
- *dma_addr = ib_dma_map_page(dev, page, 0, 1 << umem_odp->page_shift,
- DMA_BIDIRECTIONAL);
- if (ib_dma_mapping_error(dev, *dma_addr)) {
- *dma_addr = 0;
- return -EFAULT;
- }
- umem_odp->npages++;
- return 0;
-}
-
/**
* ib_umem_odp_map_dma_and_lock - DMA map userspace memory in an ODP MR and lock it.
*
* Maps the range passed in the argument to DMA addresses.
- * The DMA addresses of the mapped pages is updated in umem_odp->dma_list.
* Upon success the ODP MR will be locked to let caller complete its device
* page table update.
*
@@ -374,7 +331,7 @@ int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 user_virt,
range.default_flags |= HMM_PFN_REQ_WRITE;
}

- range.hmm_pfns = &(umem_odp->pfn_list[pfn_start_idx]);
+ range.hmm_pfns = &(umem_odp->map.pfn_list[pfn_start_idx]);
timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);

retry:
@@ -425,16 +382,6 @@ int ib_umem_odp_map_dma_and_lock(struct ib_umem_odp *umem_odp, u64 user_virt,
__func__, hmm_order, page_shift);
break;
}
-
- ret = ib_umem_odp_map_dma_single_page(
- umem_odp, dma_index,
- hmm_pfn_to_page(range.hmm_pfns[pfn_index]));
- if (ret < 0) {
- ibdev_dbg(umem_odp->umem.ibdev,
- "ib_umem_odp_map_dma_single_page failed with error %d\n", ret);
- break;
- }
- range.hmm_pfns[pfn_index] |= HMM_PFN_DMA_MAPPED;
}
/* upon success lock should stay on hold for the callee */
if (!ret)
@@ -454,32 +401,23 @@ EXPORT_SYMBOL(ib_umem_odp_map_dma_and_lock);
void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
u64 bound)
{
- dma_addr_t dma;
- int idx;
- u64 addr;
struct ib_device *dev = umem_odp->umem.ibdev;
+ u64 addr;

lockdep_assert_held(&umem_odp->umem_mutex);

virt = max_t(u64, virt, ib_umem_start(umem_odp));
bound = min_t(u64, bound, ib_umem_end(umem_odp));
for (addr = virt; addr < bound; addr += BIT(umem_odp->page_shift)) {
- unsigned long pfn_idx = (addr - ib_umem_start(umem_odp)) >>
- PAGE_SHIFT;
- struct page *page =
- hmm_pfn_to_page(umem_odp->pfn_list[pfn_idx]);
-
- idx = (addr - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
- dma = umem_odp->dma_list[idx];
+ u64 offset = addr - ib_umem_start(umem_odp);
+ size_t idx = offset >> umem_odp->page_shift;
+ unsigned long pfn = umem_odp->map.pfn_list[idx];

- if (!(umem_odp->pfn_list[pfn_idx] & HMM_PFN_VALID))
- goto clear;
- if (!(umem_odp->pfn_list[pfn_idx] & HMM_PFN_DMA_MAPPED))
+ if (!hmm_dma_unmap_pfn(dev->dma_device, &umem_odp->map, idx))
goto clear;

- ib_dma_unmap_page(dev, dma, BIT(umem_odp->page_shift),
- DMA_BIDIRECTIONAL);
- if (umem_odp->pfn_list[pfn_idx] & HMM_PFN_WRITE) {
+ if (pfn & HMM_PFN_WRITE) {
+ struct page *page = hmm_pfn_to_page(pfn);
struct page *head_page = compound_head(page);
/*
* set_page_dirty prefers being called with
@@ -494,7 +432,7 @@ void ib_umem_odp_unmap_dma_pages(struct ib_umem_odp *umem_odp, u64 virt,
}
umem_odp->npages--;
clear:
- umem_odp->pfn_list[pfn_idx] &= ~HMM_PFN_FLAGS;
+ umem_odp->map.pfn_list[idx] &= ~HMM_PFN_FLAGS;
}
}
EXPORT_SYMBOL(ib_umem_odp_unmap_dma_pages);
diff --git a/drivers/infiniband/hw/mlx5/mlx5_ib.h b/drivers/infiniband/hw/mlx5/mlx5_ib.h
index 7424b23bb0d9..27fbf5f3a2d6 100644
--- a/drivers/infiniband/hw/mlx5/mlx5_ib.h
+++ b/drivers/infiniband/hw/mlx5/mlx5_ib.h
@@ -1474,8 +1474,8 @@ void mlx5_ib_odp_cleanup_one(struct mlx5_ib_dev *ibdev);
int __init mlx5_ib_odp_init(void);
void mlx5_ib_odp_cleanup(void);
int mlx5_odp_init_mkey_cache(struct mlx5_ib_dev *dev);
-void mlx5_odp_populate_xlt(void *xlt, size_t idx, size_t nentries,
- struct mlx5_ib_mr *mr, int flags);
+int mlx5_odp_populate_xlt(void *xlt, size_t idx, size_t nentries,
+ struct mlx5_ib_mr *mr, int flags);

int mlx5_ib_advise_mr_prefetch(struct ib_pd *pd,
enum ib_uverbs_advise_mr_advice advice,
@@ -1496,8 +1496,11 @@ static inline int mlx5_odp_init_mkey_cache(struct mlx5_ib_dev *dev)
{
return 0;
}
-static inline void mlx5_odp_populate_xlt(void *xlt, size_t idx, size_t nentries,
- struct mlx5_ib_mr *mr, int flags) {}
+static inline int mlx5_odp_populate_xlt(void *xlt, size_t idx, size_t nentries,
+ struct mlx5_ib_mr *mr, int flags)
+{
+ return -EOPNOTSUPP;
+}

static inline int
mlx5_ib_advise_mr_prefetch(struct ib_pd *pd,
diff --git a/drivers/infiniband/hw/mlx5/odp.c b/drivers/infiniband/hw/mlx5/odp.c
index 6074c541885c..eaa2f9f5f3a9 100644
--- a/drivers/infiniband/hw/mlx5/odp.c
+++ b/drivers/infiniband/hw/mlx5/odp.c
@@ -35,6 +35,8 @@
#include <linux/dma-buf.h>
#include <linux/dma-resv.h>
#include <linux/hmm.h>
+#include <linux/hmm-dma.h>
+#include <linux/pci-p2pdma.h>

#include "mlx5_ib.h"
#include "cmd.h"
@@ -159,40 +161,50 @@ static void populate_klm(struct mlx5_klm *pklm, size_t idx, size_t nentries,
}
}

-static void populate_mtt(__be64 *pas, size_t idx, size_t nentries,
- struct mlx5_ib_mr *mr, int flags)
+static int populate_mtt(__be64 *pas, size_t start, size_t nentries,
+ struct mlx5_ib_mr *mr, int flags)
{
struct ib_umem_odp *odp = to_ib_umem_odp(mr->umem);
bool downgrade = flags & MLX5_IB_UPD_XLT_DOWNGRADE;
- unsigned long pfn;
- dma_addr_t pa;
+ struct pci_p2pdma_map_state p2pdma_state = {};
+ struct ib_device *dev = odp->umem.ibdev;
size_t i;

if (flags & MLX5_IB_UPD_XLT_ZAP)
- return;
+ return 0;

for (i = 0; i < nentries; i++) {
- pfn = odp->pfn_list[idx + i];
+ unsigned long pfn = odp->map.pfn_list[start + i];
+ dma_addr_t dma_addr;
+
+ pfn = odp->map.pfn_list[start + i];
if (!(pfn & HMM_PFN_VALID))
/* ODP initialization */
continue;

- pa = odp->dma_list[idx + i];
- pa |= MLX5_IB_MTT_READ;
+ dma_addr = hmm_dma_map_pfn(dev->dma_device, &odp->map,
+ start + i, &p2pdma_state);
+ if (ib_dma_mapping_error(dev, dma_addr))
+ return -EFAULT;
+
+ dma_addr |= MLX5_IB_MTT_READ;
if ((pfn & HMM_PFN_WRITE) && !downgrade)
- pa |= MLX5_IB_MTT_WRITE;
+ dma_addr |= MLX5_IB_MTT_WRITE;

- pas[i] = cpu_to_be64(pa);
+ pas[i] = cpu_to_be64(dma_addr);
+ odp->npages++;
}
+ return 0;
}

-void mlx5_odp_populate_xlt(void *xlt, size_t idx, size_t nentries,
- struct mlx5_ib_mr *mr, int flags)
+int mlx5_odp_populate_xlt(void *xlt, size_t idx, size_t nentries,
+ struct mlx5_ib_mr *mr, int flags)
{
if (flags & MLX5_IB_UPD_XLT_INDIRECT) {
populate_klm(xlt, idx, nentries, mr, flags);
+ return 0;
} else {
- populate_mtt(xlt, idx, nentries, mr, flags);
+ return populate_mtt(xlt, idx, nentries, mr, flags);
}
}

@@ -303,7 +315,7 @@ static bool mlx5_ib_invalidate_range(struct mmu_interval_notifier *mni,
* estimate the cost of another UMR vs. the cost of bigger
* UMR.
*/
- if (umem_odp->pfn_list[idx] & HMM_PFN_VALID) {
+ if (umem_odp->map.pfn_list[idx] & HMM_PFN_VALID) {
if (!in_block) {
blk_start_idx = idx;
in_block = 1;
diff --git a/drivers/infiniband/hw/mlx5/umr.c b/drivers/infiniband/hw/mlx5/umr.c
index 793f3c5c4d01..5be4426a2884 100644
--- a/drivers/infiniband/hw/mlx5/umr.c
+++ b/drivers/infiniband/hw/mlx5/umr.c
@@ -840,7 +840,17 @@ int mlx5r_umr_update_xlt(struct mlx5_ib_mr *mr, u64 idx, int npages,
size_to_map = npages * desc_size;
dma_sync_single_for_cpu(ddev, sg.addr, sg.length,
DMA_TO_DEVICE);
- mlx5_odp_populate_xlt(xlt, idx, npages, mr, flags);
+ /*
+ * npages is the maximum number of pages to map, but we
+ * can't guarantee that all pages are actually mapped.
+ *
+ * For example, if page is p2p of type which is not supported
+ * for mapping, the number of pages mapped will be less than
+ * requested.
+ */
+ err = mlx5_odp_populate_xlt(xlt, idx, npages, mr, flags);
+ if (err)
+ return err;
dma_sync_single_for_device(ddev, sg.addr, sg.length,
DMA_TO_DEVICE);
sg.length = ALIGN(size_to_map, MLX5_UMR_FLEX_ALIGNMENT);
diff --git a/drivers/infiniband/sw/rxe/rxe_odp.c b/drivers/infiniband/sw/rxe/rxe_odp.c
index caedd9ef2fe3..51b28f5d5027 100644
--- a/drivers/infiniband/sw/rxe/rxe_odp.c
+++ b/drivers/infiniband/sw/rxe/rxe_odp.c
@@ -194,7 +194,7 @@ static int __rxe_odp_mr_copy(struct rxe_mr *mr, u64 iova, void *addr,
while (length > 0) {
u8 *src, *dest;

- page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
+ page = hmm_pfn_to_page(umem_odp->map.pfn_list[idx]);
user_va = kmap_local_page(page);
if (!user_va)
return -EFAULT;
@@ -277,7 +277,7 @@ static int rxe_odp_do_atomic_op(struct rxe_mr *mr, u64 iova, int opcode,

idx = (iova - ib_umem_start(umem_odp)) >> umem_odp->page_shift;
page_offset = iova & (BIT(umem_odp->page_shift) - 1);
- page = hmm_pfn_to_page(umem_odp->pfn_list[idx]);
+ page = hmm_pfn_to_page(umem_odp->map.pfn_list[idx]);
if (!page)
return RESPST_ERR_RKEY_VIOLATION;

diff --git a/include/rdma/ib_umem_odp.h b/include/rdma/ib_umem_odp.h
index a345c26a745d..2a24bf791c10 100644
--- a/include/rdma/ib_umem_odp.h
+++ b/include/rdma/ib_umem_odp.h
@@ -8,24 +8,17 @@

#include <rdma/ib_umem.h>
#include <rdma/ib_verbs.h>
-#include <linux/hmm.h>
+#include <linux/hmm-dma.h>

struct ib_umem_odp {
struct ib_umem umem;
struct mmu_interval_notifier notifier;
struct pid *tgid;

- /* An array of the pfns included in the on-demand paging umem. */
- unsigned long *pfn_list;
+ struct hmm_dma_map map;

/*
- * An array with DMA addresses mapped for pfns in pfn_list.
- * The lower two bits designate access permissions.
- * See ODP_READ_ALLOWED_BIT and ODP_WRITE_ALLOWED_BIT.
- */
- dma_addr_t *dma_list;
- /*
- * The umem_mutex protects the page_list and dma_list fields of an ODP
+ * The umem_mutex protects the page_list field of an ODP
* umem, allowing only a single thread to map/unmap pages. The mutex
* also protects access to the mmu notifier counters.
*/
--
2.49.0