IB/mlx5: Add mlx5_ib_update_mtt to update page tables after creation
The new function allows updating the page tables of a memory region
after it was created. This can be used to handle page faults and page
invalidations.
Since mlx5_ib_update_mtt will need to work from within page invalidation,
so it must not block on memory allocation. It employs an atomic memory
allocation mechanism that is used as a fallback when kmalloc(GFP_ATOMIC) fails.
In order to reuse code from mlx5_ib_populate_pas, the patch splits
this function and add the needed parameters.
Signed-off-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Shachar Raindel <raindel@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
diff --git a/drivers/infiniband/hw/mlx5/mr.c b/drivers/infiniband/hw/mlx5/mr.c
index 49fc3ca..38b0626 100644
--- a/drivers/infiniband/hw/mlx5/mr.c
+++ b/drivers/infiniband/hw/mlx5/mr.c
@@ -44,9 +44,13 @@
MAX_PENDING_REG_MR = 8,
};
-enum {
- MLX5_UMR_ALIGN = 2048
-};
+#define MLX5_UMR_ALIGN 2048
+#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
+static __be64 mlx5_ib_update_mtt_emergency_buffer[
+ MLX5_UMR_MTT_MIN_CHUNK_SIZE/sizeof(__be64)]
+ __aligned(MLX5_UMR_ALIGN);
+static DEFINE_MUTEX(mlx5_ib_update_mtt_emergency_buffer_mutex);
+#endif
static int order2idx(struct mlx5_ib_dev *dev, int order)
{
@@ -822,6 +826,128 @@
return mr;
}
+#ifdef CONFIG_INFINIBAND_ON_DEMAND_PAGING
+int mlx5_ib_update_mtt(struct mlx5_ib_mr *mr, u64 start_page_index, int npages,
+ int zap)
+{
+ struct mlx5_ib_dev *dev = mr->dev;
+ struct device *ddev = dev->ib_dev.dma_device;
+ struct umr_common *umrc = &dev->umrc;
+ struct mlx5_ib_umr_context umr_context;
+ struct ib_umem *umem = mr->umem;
+ int size;
+ __be64 *pas;
+ dma_addr_t dma;
+ struct ib_send_wr wr, *bad;
+ struct mlx5_umr_wr *umrwr = (struct mlx5_umr_wr *)&wr.wr.fast_reg;
+ struct ib_sge sg;
+ int err = 0;
+ const int page_index_alignment = MLX5_UMR_MTT_ALIGNMENT / sizeof(u64);
+ const int page_index_mask = page_index_alignment - 1;
+ size_t pages_mapped = 0;
+ size_t pages_to_map = 0;
+ size_t pages_iter = 0;
+ int use_emergency_buf = 0;
+
+ /* UMR copies MTTs in units of MLX5_UMR_MTT_ALIGNMENT bytes,
+ * so we need to align the offset and length accordingly */
+ if (start_page_index & page_index_mask) {
+ npages += start_page_index & page_index_mask;
+ start_page_index &= ~page_index_mask;
+ }
+
+ pages_to_map = ALIGN(npages, page_index_alignment);
+
+ if (start_page_index + pages_to_map > MLX5_MAX_UMR_PAGES)
+ return -EINVAL;
+
+ size = sizeof(u64) * pages_to_map;
+ size = min_t(int, PAGE_SIZE, size);
+ /* We allocate with GFP_ATOMIC to avoid recursion into page-reclaim
+ * code, when we are called from an invalidation. The pas buffer must
+ * be 2k-aligned for Connect-IB. */
+ pas = (__be64 *)get_zeroed_page(GFP_ATOMIC);
+ if (!pas) {
+ mlx5_ib_warn(dev, "unable to allocate memory during MTT update, falling back to slower chunked mechanism.\n");
+ pas = mlx5_ib_update_mtt_emergency_buffer;
+ size = MLX5_UMR_MTT_MIN_CHUNK_SIZE;
+ use_emergency_buf = 1;
+ mutex_lock(&mlx5_ib_update_mtt_emergency_buffer_mutex);
+ memset(pas, 0, size);
+ }
+ pages_iter = size / sizeof(u64);
+ dma = dma_map_single(ddev, pas, size, DMA_TO_DEVICE);
+ if (dma_mapping_error(ddev, dma)) {
+ mlx5_ib_err(dev, "unable to map DMA during MTT update.\n");
+ err = -ENOMEM;
+ goto free_pas;
+ }
+
+ for (pages_mapped = 0;
+ pages_mapped < pages_to_map && !err;
+ pages_mapped += pages_iter, start_page_index += pages_iter) {
+ dma_sync_single_for_cpu(ddev, dma, size, DMA_TO_DEVICE);
+
+ npages = min_t(size_t,
+ pages_iter,
+ ib_umem_num_pages(umem) - start_page_index);
+
+ if (!zap) {
+ __mlx5_ib_populate_pas(dev, umem, PAGE_SHIFT,
+ start_page_index, npages, pas,
+ MLX5_IB_MTT_PRESENT);
+ /* Clear padding after the pages brought from the
+ * umem. */
+ memset(pas + npages, 0, size - npages * sizeof(u64));
+ }
+
+ dma_sync_single_for_device(ddev, dma, size, DMA_TO_DEVICE);
+
+ memset(&wr, 0, sizeof(wr));
+ wr.wr_id = (u64)(unsigned long)&umr_context;
+
+ sg.addr = dma;
+ sg.length = ALIGN(npages * sizeof(u64),
+ MLX5_UMR_MTT_ALIGNMENT);
+ sg.lkey = dev->umrc.mr->lkey;
+
+ wr.send_flags = MLX5_IB_SEND_UMR_FAIL_IF_FREE |
+ MLX5_IB_SEND_UMR_UPDATE_MTT;
+ wr.sg_list = &sg;
+ wr.num_sge = 1;
+ wr.opcode = MLX5_IB_WR_UMR;
+ umrwr->npages = sg.length / sizeof(u64);
+ umrwr->page_shift = PAGE_SHIFT;
+ umrwr->mkey = mr->mmr.key;
+ umrwr->target.offset = start_page_index;
+
+ mlx5_ib_init_umr_context(&umr_context);
+ down(&umrc->sem);
+ err = ib_post_send(umrc->qp, &wr, &bad);
+ if (err) {
+ mlx5_ib_err(dev, "UMR post send failed, err %d\n", err);
+ } else {
+ wait_for_completion(&umr_context.done);
+ if (umr_context.status != IB_WC_SUCCESS) {
+ mlx5_ib_err(dev, "UMR completion failed, code %d\n",
+ umr_context.status);
+ err = -EFAULT;
+ }
+ }
+ up(&umrc->sem);
+ }
+ dma_unmap_single(ddev, dma, size, DMA_TO_DEVICE);
+
+free_pas:
+ if (!use_emergency_buf)
+ free_page((unsigned long)pas);
+ else
+ mutex_unlock(&mlx5_ib_update_mtt_emergency_buffer_mutex);
+
+ return err;
+}
+#endif
+
static struct mlx5_ib_mr *reg_create(struct ib_pd *pd, u64 virt_addr,
u64 length, struct ib_umem *umem,
int npages, int page_shift,