RDMA/mlx5: Use ib_umem_find_best_pgsz() for devx

Since devx uses the new rdma_for_each_block() to fill the PAS it can also
use ib_umem_find_best_pgsz().

However, the umem constructionin devx is complicated, the umem must still
respect all the HW limits such as page_offset_quantized and the IOVA
alignment.

Since we don't know what the user intends to use the umem for we have to
limit it to PAGE_SIZE.

There are users trying to mix umem's with mkeys so this makes them work
reliably, at least for an identity IOVA, by ensuring the IOVA matches the
selected page size.

Last user of mlx5_ib_get_buf_offset() so it can also be removed.

Fixes: aeae94579caf ("IB/mlx5: Add DEVX support for memory registration")
Link: https://lore.kernel.org/r/20201115114311.136250-7-leon@kernel.org
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

1 files changed, 35 insertions, 31 deletions

diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c
index f6839472b6fb..7c3eefba6197 100644
--- a/drivers/infiniband/hw/mlx5/devx.c
+++ b/drivers/infiniband/hw/mlx5/devx.c
@@ -93,8 +93,6 @@ struct devx_async_event_file {
 struct devx_umem {
 	struct mlx5_core_dev		*mdev;
 	struct ib_umem			*umem;
-	u32				page_offset;
-	int				page_shift;
 	u32				dinlen;
 	u32				dinbox[MLX5_ST_SZ_DW(general_obj_in_cmd_hdr)];
 };
@@ -2057,7 +2055,6 @@ static int devx_umem_get(struct mlx5_ib_dev *dev, struct ib_ucontext *ucontext,
 	size_t size;
 	u32 access;
 	int err;
-	u32 page_mask;
 
 	if (uverbs_copy_from(&addr, attrs, MLX5_IB_ATTR_DEVX_UMEM_REG_ADDR) ||
 	    uverbs_copy_from(&size, attrs, MLX5_IB_ATTR_DEVX_UMEM_REG_LEN))
@@ -2078,46 +2075,55 @@ static int devx_umem_get(struct mlx5_ib_dev *dev, struct ib_ucontext *ucontext,
 	obj->umem = ib_umem_get(&dev->ib_dev, addr, size, access);
 	if (IS_ERR(obj->umem))
 		return PTR_ERR(obj->umem);
-
-	mlx5_ib_cont_pages(obj->umem, obj->umem->address,
-			   MLX5_MKEY_PAGE_SHIFT_MASK, &obj->page_shift);
-	page_mask = (1 << obj->page_shift) - 1;
-	obj->page_offset = obj->umem->address & page_mask;
-
 	return 0;
 }
 
-static int devx_umem_reg_cmd_alloc(struct uverbs_attr_bundle *attrs,
+static int devx_umem_reg_cmd_alloc(struct mlx5_ib_dev *dev,
+				   struct uverbs_attr_bundle *attrs,
 				   struct devx_umem *obj,
 				   struct devx_umem_reg_cmd *cmd)
 {
-	cmd->inlen =
-		MLX5_ST_SZ_BYTES(create_umem_in) +
-		(MLX5_ST_SZ_BYTES(mtt) *
-		 ib_umem_num_dma_blocks(obj->umem, 1UL << obj->page_shift));
-	cmd->in = uverbs_zalloc(attrs, cmd->inlen);
-	return PTR_ERR_OR_ZERO(cmd->in);
-}
-
-static void devx_umem_reg_cmd_build(struct mlx5_ib_dev *dev,
-				    struct devx_umem *obj,
-				    struct devx_umem_reg_cmd *cmd)
-{
-	void *umem;
+	unsigned int page_size;
 	__be64 *mtt;
+	void *umem;
+
+	/*
+	 * We don't know what the user intends to use this umem for, but the HW
+	 * restrictions must be met. MR, doorbell records, QP, WQ and CQ all
+	 * have different requirements. Since we have no idea how to sort this
+	 * out, only support PAGE_SIZE with the expectation that userspace will
+	 * provide the necessary alignments inside the known PAGE_SIZE and that
+	 * FW will check everything.
+	 */
+	page_size = ib_umem_find_best_pgoff(
+		obj->umem, PAGE_SIZE,
+		__mlx5_page_offset_to_bitmask(__mlx5_bit_sz(umem, page_offset),
+					      0));
+	if (!page_size)
+		return -EINVAL;
+
+	cmd->inlen = MLX5_ST_SZ_BYTES(create_umem_in) +
+		     (MLX5_ST_SZ_BYTES(mtt) *
+		      ib_umem_num_dma_blocks(obj->umem, page_size));
+	cmd->in = uverbs_zalloc(attrs, cmd->inlen);
+	if (!cmd->in)
+		return PTR_ERR(cmd->in);
 
 	umem = MLX5_ADDR_OF(create_umem_in, cmd->in, umem);
 	mtt = (__be64 *)MLX5_ADDR_OF(umem, umem, mtt);
 
 	MLX5_SET(create_umem_in, cmd->in, opcode, MLX5_CMD_OP_CREATE_UMEM);
 	MLX5_SET64(umem, umem, num_of_mtt,
-		   ib_umem_num_dma_blocks(obj->umem, 1UL << obj->page_shift));
-	MLX5_SET(umem, umem, log_page_size, obj->page_shift -
-					    MLX5_ADAPTER_PAGE_SHIFT);
-	MLX5_SET(umem, umem, page_offset, obj->page_offset);
-	mlx5_ib_populate_pas(obj->umem, 1UL << obj->page_shift, mtt,
+		   ib_umem_num_dma_blocks(obj->umem, page_size));
+	MLX5_SET(umem, umem, log_page_size,
+		 order_base_2(page_size) - MLX5_ADAPTER_PAGE_SHIFT);
+	MLX5_SET(umem, umem, page_offset,
+		 ib_umem_dma_offset(obj->umem, page_size));
+
+	mlx5_ib_populate_pas(obj->umem, page_size, mtt,
 			     (obj->umem->writable ? MLX5_IB_MTT_WRITE : 0) |
 				     MLX5_IB_MTT_READ);
+	return 0;
 }
 
 static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_UMEM_REG)(
@@ -2144,12 +2150,10 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_UMEM_REG)(
 	if (err)
 		goto err_obj_free;
 
-	err = devx_umem_reg_cmd_alloc(attrs, obj, &cmd);
+	err = devx_umem_reg_cmd_alloc(dev, attrs, obj, &cmd);
 	if (err)
 		goto err_umem_release;
 
-	devx_umem_reg_cmd_build(dev, obj, &cmd);
-
 	MLX5_SET(create_umem_in, cmd.in, uid, c->devx_uid);
 	err = mlx5_cmd_exec(dev->mdev, cmd.in, cmd.inlen, cmd.out,
 			    sizeof(cmd.out));