IB/uverbs: Add UVERBS_ATTR_FLAGS_IN to the specs language

This clearly indicates that the input is a bitwise combination of values
in an enum, and identifies which enum contains the definition of the bits.

Special accessors are provided that handle the mandatory validation of the
allowed bits and enforce the correct type for bitwise flags.

If we had introduced this at the start then the kabi would have uniformly
used u64 data to pass flags, however today there is a mixture of u64 and
u32 flags. All places are converted to accept both sizes and the accessor
fixes it. This allows all existing flags to grow to u64 in future without
any hassle.

Finally all flags are, by definition, optional. If flags are not passed
the accessor does not fail, but provides a value of zero.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>

drivers/infiniband/core/uverbs_ioctl.c

@@ -486,3 +486,54 @@ long ib_uverbs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 	return err;
 }
+
+int uverbs_get_flags64(u64 *to, const struct uverbs_attr_bundle *attrs_bundle,
+		       size_t idx, u64 allowed_bits)
+{
+	const struct uverbs_attr *attr;
+	u64 flags;
+
+	attr = uverbs_attr_get(attrs_bundle, idx);
+	/* Missing attribute means 0 flags */
+	if (IS_ERR(attr)) {
+		*to = 0;
+		return 0;
+	}
+
+	/*
+	 * New userspace code should use 8 bytes to pass flags, but we
+	 * transparently support old userspaces that were using 4 bytes as
+	 * well.
+	 */
+	if (attr->ptr_attr.len == 8)
+		flags = attr->ptr_attr.data;
+	else if (attr->ptr_attr.len == 4)
+		memcpy(&flags, &attr->ptr_attr.data, 4);
+	else
+		return -EINVAL;
+
+	if (flags & ~allowed_bits)
+		return -EINVAL;
+
+	*to = flags;
+	return 0;
+}
+EXPORT_SYMBOL(uverbs_get_flags64);
+
+int uverbs_get_flags32(u32 *to, const struct uverbs_attr_bundle *attrs_bundle,
+		       size_t idx, u64 allowed_bits)
+{
+	u64 flags;
+	int ret;
+
+	ret = uverbs_get_flags64(&flags, attrs_bundle, idx, allowed_bits);
+	if (ret)
+		return ret;
+
+	if (flags > U32_MAX)
+		return -EINVAL;
+	*to = flags;
+
+	return 0;
+}
+EXPORT_SYMBOL(uverbs_get_flags32);

drivers/infiniband/core/uverbs_std_types_counters.c

@@ -97,8 +97,9 @@ static int UVERBS_HANDLER(UVERBS_METHOD_COUNTERS_READ)(struct ib_device *ib_dev,
 	if (!atomic_read(&counters->usecnt))
 		return -EINVAL;
 
-	ret = uverbs_copy_from(&read_attr.flags, attrs,
-			       UVERBS_ATTR_READ_COUNTERS_FLAGS);
+	ret = uverbs_get_flags32(&read_attr.flags, attrs,
+				 UVERBS_ATTR_READ_COUNTERS_FLAGS,
+				 IB_UVERBS_READ_COUNTERS_PREFER_CACHED);
 	if (ret)
 		return ret;
 
@@ -147,9 +148,8 @@ DECLARE_UVERBS_NAMED_METHOD(
 	UVERBS_ATTR_PTR_OUT(UVERBS_ATTR_READ_COUNTERS_BUFF,
 			    UVERBS_ATTR_MIN_SIZE(0),
 			    UA_MANDATORY),
-	UVERBS_ATTR_PTR_IN(UVERBS_ATTR_READ_COUNTERS_FLAGS,
-			   UVERBS_ATTR_TYPE(__u32),
-			   UA_MANDATORY));
+	UVERBS_ATTR_FLAGS_IN(UVERBS_ATTR_READ_COUNTERS_FLAGS,
+			     enum ib_uverbs_read_counters_flags));
 
 DECLARE_UVERBS_NAMED_OBJECT(UVERBS_OBJECT_COUNTERS,
 			    UVERBS_TYPE_ALLOC_IDR(uverbs_free_counters),

drivers/infiniband/core/uverbs_std_types_cq.c

@@ -84,10 +84,12 @@ static int UVERBS_HANDLER(UVERBS_METHOD_CQ_CREATE)(struct ib_device *ib_dev,
 	if (ret)
 		return ret;
 
-	/* Optional param, if it doesn't exist, we get -ENOENT and skip it */
-	if (IS_UVERBS_COPY_ERR(uverbs_copy_from(&attr.flags, attrs,
-						UVERBS_ATTR_CREATE_CQ_FLAGS)))
-		return -EFAULT;
+	ret = uverbs_get_flags32(&attr.flags, attrs,
+				 UVERBS_ATTR_CREATE_CQ_FLAGS,
+				 IB_UVERBS_CQ_FLAGS_TIMESTAMP_COMPLETION |
+					 IB_UVERBS_CQ_FLAGS_IGNORE_OVERRUN);
+	if (ret)
+		return ret;
 
 	ev_file_uobj = uverbs_attr_get_uobject(attrs, UVERBS_ATTR_CREATE_CQ_COMP_CHANNEL);
 	if (!IS_ERR(ev_file_uobj)) {
@@ -164,7 +166,8 @@ DECLARE_UVERBS_NAMED_METHOD(
 	UVERBS_ATTR_PTR_IN(UVERBS_ATTR_CREATE_CQ_COMP_VECTOR,
 			   UVERBS_ATTR_TYPE(u32),
 			   UA_MANDATORY),
-	UVERBS_ATTR_PTR_IN(UVERBS_ATTR_CREATE_CQ_FLAGS, UVERBS_ATTR_TYPE(u32)),
+	UVERBS_ATTR_FLAGS_IN(UVERBS_ATTR_CREATE_CQ_FLAGS,
+			     enum ib_uverbs_ex_create_cq_flags),
 	UVERBS_ATTR_PTR_OUT(UVERBS_ATTR_CREATE_CQ_RESP_CQE,
 			    UVERBS_ATTR_TYPE(u32),
 			    UA_MANDATORY),

drivers/infiniband/core/uverbs_std_types_mr.c

@@ -62,8 +62,9 @@ static int UVERBS_HANDLER(UVERBS_METHOD_DM_MR_REG)(struct ib_device *ib_dev,
 	if (ret)
 		return ret;
 
-	ret = uverbs_copy_from(&attr.access_flags, attrs,
-			       UVERBS_ATTR_REG_DM_MR_ACCESS_FLAGS);
+	ret = uverbs_get_flags32(&attr.access_flags, attrs,
+				 UVERBS_ATTR_REG_DM_MR_ACCESS_FLAGS,
+				 IB_ACCESS_SUPPORTED);
 	if (ret)
 		return ret;
 
@@ -131,9 +132,8 @@ DECLARE_UVERBS_NAMED_METHOD(
 			UVERBS_OBJECT_PD,
 			UVERBS_ACCESS_READ,
 			UA_MANDATORY),
-	UVERBS_ATTR_PTR_IN(UVERBS_ATTR_REG_DM_MR_ACCESS_FLAGS,
-			   UVERBS_ATTR_TYPE(u32),
-			   UA_MANDATORY),
+	UVERBS_ATTR_FLAGS_IN(UVERBS_ATTR_REG_DM_MR_ACCESS_FLAGS,
+			     enum ib_access_flags),
 	UVERBS_ATTR_IDR(UVERBS_ATTR_REG_DM_MR_DM_HANDLE,
 			UVERBS_OBJECT_DM,
 			UVERBS_ACCESS_READ,

drivers/infiniband/hw/mlx5/devx.c

@@ -858,16 +858,21 @@ static int devx_umem_get(struct mlx5_ib_dev *dev, struct ib_ucontext *ucontext,
 {
 	u64 addr;
 	size_t size;
-	int access;
+	u32 access;
 	int npages;
 	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) ||
-	    uverbs_copy_from(&access, attrs, MLX5_IB_ATTR_DEVX_UMEM_REG_ACCESS))
+	    uverbs_copy_from(&size, attrs, MLX5_IB_ATTR_DEVX_UMEM_REG_LEN))
 		return -EFAULT;
 
+	err = uverbs_get_flags32(&access, attrs,
+				 MLX5_IB_ATTR_DEVX_UMEM_REG_ACCESS,
+				 IB_ACCESS_SUPPORTED);
+	if (err)
+		return err;
+
 	err = ib_check_mr_access(access);
 	if (err)
 		return err;
@@ -1012,9 +1017,8 @@ DECLARE_UVERBS_NAMED_METHOD(
 	UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_DEVX_UMEM_REG_LEN,
 			   UVERBS_ATTR_TYPE(u64),
 			   UA_MANDATORY),
-	UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_DEVX_UMEM_REG_ACCESS,
-			   UVERBS_ATTR_TYPE(u32),
-			   UA_MANDATORY),
+	UVERBS_ATTR_FLAGS_IN(MLX5_IB_ATTR_DEVX_UMEM_REG_ACCESS,
+			     enum ib_access_flags),
 	UVERBS_ATTR_PTR_OUT(MLX5_IB_ATTR_DEVX_UMEM_REG_OUT_ID,
 			    UVERBS_ATTR_TYPE(u32),
 			    UA_MANDATORY));

drivers/infiniband/hw/mlx5/main.c

@@ -3859,12 +3859,11 @@ mlx5_ib_create_flow_action_esp(struct ib_device *device,
 	u64 flags;
 	int err = 0;
 
-	if (IS_UVERBS_COPY_ERR(uverbs_copy_from(&action_flags, attrs,
-						MLX5_IB_ATTR_CREATE_FLOW_ACTION_FLAGS)))
-		return ERR_PTR(-EFAULT);
-
-	if (action_flags >= (MLX5_FLOW_ACTION_ESP_CREATE_LAST_SUPPORTED << 1))
-		return ERR_PTR(-EOPNOTSUPP);
+	err = uverbs_get_flags64(
+		&action_flags, attrs, MLX5_IB_ATTR_CREATE_FLOW_ACTION_FLAGS,
+		((MLX5_FLOW_ACTION_ESP_CREATE_LAST_SUPPORTED << 1) - 1));
+	if (err)
+		return ERR_PTR(err);
 
 	flags = mlx5_ib_flow_action_flags_to_accel_xfrm_flags(action_flags);
 
@@ -5531,9 +5530,8 @@ ADD_UVERBS_ATTRIBUTES_SIMPLE(
 	mlx5_ib_flow_action,
 	UVERBS_OBJECT_FLOW_ACTION,
 	UVERBS_METHOD_FLOW_ACTION_ESP_CREATE,
-	UVERBS_ATTR_PTR_IN(MLX5_IB_ATTR_CREATE_FLOW_ACTION_FLAGS,
-			   UVERBS_ATTR_TYPE(u64),
-			   UA_MANDATORY));
+	UVERBS_ATTR_FLAGS_IN(MLX5_IB_ATTR_CREATE_FLOW_ACTION_FLAGS,
+			     enum mlx5_ib_uapi_flow_action_flags));
 
 #define NUM_TREES	5
 static int populate_specs_root(struct mlx5_ib_dev *dev)

include/rdma/uverbs_ioctl.h

@@ -268,6 +268,19 @@ struct uverbs_object_tree_def {
 			  __VA_ARGS__ },                                       \
 	})
 
+/*
+ * An input value that is a bitwise combination of values of _enum_type.
+ * This permits the flag value to be passed as either a u32 or u64, it must
+ * be retrieved via uverbs_get_flag().
+ */
+#define UVERBS_ATTR_FLAGS_IN(_attr_id, _enum_type, ...)                        \
+	UVERBS_ATTR_PTR_IN(                                                    \
+		_attr_id,                                                      \
+		UVERBS_ATTR_SIZE(sizeof(u32) + BUILD_BUG_ON_ZERO(              \
+						       !sizeof(_enum_type *)), \
+				 sizeof(u64)),                                 \
+		__VA_ARGS__)
+
 /*
  * This spec is used in order to pass information to the hardware driver in a
  * legacy way. Every verb that could get driver specific data should get this
@@ -520,6 +533,26 @@ static inline int _uverbs_copy_from_or_zero(void *to,
 #define uverbs_copy_from_or_zero(to, attrs_bundle, idx)			      \
 	_uverbs_copy_from_or_zero(to, attrs_bundle, idx, sizeof(*to))
 
+#if IS_ENABLED(CONFIG_INFINIBAND_USER_ACCESS)
+int uverbs_get_flags64(u64 *to, const struct uverbs_attr_bundle *attrs_bundle,
+		       size_t idx, u64 allowed_bits);
+int uverbs_get_flags32(u32 *to, const struct uverbs_attr_bundle *attrs_bundle,
+		       size_t idx, u64 allowed_bits);
+#else
+static inline int
+uverbs_get_flags64(u64 *to, const struct uverbs_attr_bundle *attrs_bundle,
+		   size_t idx, u64 allowed_bits)
+{
+	return -EINVAL;
+}
+static inline int
+uverbs_get_flags32(u32 *to, const struct uverbs_attr_bundle *attrs_bundle,
+		   size_t idx, u64 allowed_bits)
+{
+	return -EINVAL;
+}
+#endif
+
 /* =================================================
  *	 Definitions -> Specs infrastructure
  * =================================================