IB/uverbs: Add IDRs array attribute type to ioctl() interface

Methods sometimes need to get a flexible set of IDRs and not a strict set
as can be achieved today by the conventional IDR attribute. Add a new
IDRS_ARRAY attribute to the generic uverbs ioctl layer.

IDRS_ARRAY points to array of idrs of the same object type and same access
rights, only write and read are supported.
Signed-off-by: Guy Levi <guyle@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>``
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/core/uverbs_ioctl.c

@@ -57,6 +57,7 @@ struct bundle_priv {
 	struct ib_uverbs_attr *uattrs;
 
 	DECLARE_BITMAP(uobj_finalize, UVERBS_API_ATTR_BKEY_LEN);
+	DECLARE_BITMAP(spec_finalize, UVERBS_API_ATTR_BKEY_LEN);
 
 	/*
 	 * Must be last. bundle ends in a flex array which overlaps
@@ -143,6 +144,86 @@ static bool uverbs_is_attr_cleared(const struct ib_uverbs_attr *uattr,
 			   0, uattr->len - len);
 }
 
+static int uverbs_process_idrs_array(struct bundle_priv *pbundle,
+				     const struct uverbs_api_attr *attr_uapi,
+				     struct uverbs_objs_arr_attr *attr,
+				     struct ib_uverbs_attr *uattr,
+				     u32 attr_bkey)
+{
+	const struct uverbs_attr_spec *spec = &attr_uapi->spec;
+	size_t array_len;
+	u32 *idr_vals;
+	int ret = 0;
+	size_t i;
+
+	if (uattr->attr_data.reserved)
+		return -EINVAL;
+
+	if (uattr->len % sizeof(u32))
+		return -EINVAL;
+
+	array_len = uattr->len / sizeof(u32);
+	if (array_len < spec->u2.objs_arr.min_len ||
+	    array_len > spec->u2.objs_arr.max_len)
+		return -EINVAL;
+
+	attr->uobjects =
+		uverbs_alloc(&pbundle->bundle,
+			     array_size(array_len, sizeof(*attr->uobjects)));
+	if (IS_ERR(attr->uobjects))
+		return PTR_ERR(attr->uobjects);
+
+	/*
+	 * Since idr is 4B and *uobjects is >= 4B, we can use attr->uobjects
+	 * to store idrs array and avoid additional memory allocation. The
+	 * idrs array is offset to the end of the uobjects array so we will be
+	 * able to read idr and replace with a pointer.
+	 */
+	idr_vals = (u32 *)(attr->uobjects + array_len) - array_len;
+
+	if (uattr->len > sizeof(uattr->data)) {
+		ret = copy_from_user(idr_vals, u64_to_user_ptr(uattr->data),
+				     uattr->len);
+		if (ret)
+			return -EFAULT;
+	} else {
+		memcpy(idr_vals, &uattr->data, uattr->len);
+	}
+
+	for (i = 0; i != array_len; i++) {
+		attr->uobjects[i] = uverbs_get_uobject_from_file(
+			spec->u2.objs_arr.obj_type, pbundle->bundle.ufile,
+			spec->u2.objs_arr.access, idr_vals[i]);
+		if (IS_ERR(attr->uobjects[i])) {
+			ret = PTR_ERR(attr->uobjects[i]);
+			break;
+		}
+	}
+
+	attr->len = i;
+	__set_bit(attr_bkey, pbundle->spec_finalize);
+	return ret;
+}
+
+static int uverbs_free_idrs_array(const struct uverbs_api_attr *attr_uapi,
+				  struct uverbs_objs_arr_attr *attr,
+				  bool commit)
+{
+	const struct uverbs_attr_spec *spec = &attr_uapi->spec;
+	int current_ret;
+	int ret = 0;
+	size_t i;
+
+	for (i = 0; i != attr->len; i++) {
+		current_ret = uverbs_finalize_object(
+			attr->uobjects[i], spec->u2.objs_arr.access, commit);
+		if (!ret)
+			ret = current_ret;
+	}
+
+	return ret;
+}
+
 static int uverbs_process_attr(struct bundle_priv *pbundle,
 			       const struct uverbs_api_attr *attr_uapi,
 			       struct ib_uverbs_attr *uattr, u32 attr_bkey)
@@ -246,6 +327,11 @@ static int uverbs_process_attr(struct bundle_priv *pbundle,
 		}
 
 		break;
+
+	case UVERBS_ATTR_TYPE_IDRS_ARRAY:
+		return uverbs_process_idrs_array(pbundle, attr_uapi,
+						 &e->objs_arr_attr, uattr,
+						 attr_bkey);
 	default:
 		return -EOPNOTSUPP;
 	}
@@ -384,6 +470,7 @@ static int bundle_destroy(struct bundle_priv *pbundle, bool commit)
 	unsigned int i;
 	int ret = 0;
 
+	/* fast path for simple uobjects */
 	i = -1;
 	while ((i = find_next_bit(pbundle->uobj_finalize, key_bitmap_len,
 				  i + 1)) < key_bitmap_len) {
@@ -397,6 +484,32 @@ static int bundle_destroy(struct bundle_priv *pbundle, bool commit)
 			ret = current_ret;
 	}
 
+	i = -1;
+	while ((i = find_next_bit(pbundle->spec_finalize, key_bitmap_len,
+				  i + 1)) < key_bitmap_len) {
+		struct uverbs_attr *attr = &pbundle->bundle.attrs[i];
+		const struct uverbs_api_attr *attr_uapi;
+		void __rcu **slot;
+		int current_ret;
+
+		slot = uapi_get_attr_for_method(
+			pbundle,
+			pbundle->method_key | uapi_bkey_to_key_attr(i));
+		if (WARN_ON(!slot))
+			continue;
+
+		attr_uapi = srcu_dereference(
+			*slot,
+			&pbundle->bundle.ufile->device->disassociate_srcu);
+
+		if (attr_uapi->spec.type == UVERBS_ATTR_TYPE_IDRS_ARRAY) {
+			current_ret = uverbs_free_idrs_array(
+				attr_uapi, &attr->objs_arr_attr, commit);
+			if (!ret)
+				ret = current_ret;
+		}
+	}
+
 	for (memblock = pbundle->allocated_mem; memblock;) {
 		struct bundle_alloc_head *tmp = memblock;
 
@@ -461,6 +574,7 @@ static int ib_uverbs_cmd_verbs(struct ib_uverbs_file *ufile,
 	memset(pbundle->bundle.attr_present, 0,
 	       sizeof(pbundle->bundle.attr_present));
 	memset(pbundle->uobj_finalize, 0, sizeof(pbundle->uobj_finalize));
+	memset(pbundle->spec_finalize, 0, sizeof(pbundle->spec_finalize));
 
 	ret = ib_uverbs_run_method(pbundle, hdr->num_attrs);
 	destroy_ret = bundle_destroy(pbundle, ret == 0);

drivers/infiniband/core/uverbs_uapi.c

@@ -73,6 +73,18 @@ static int uapi_merge_method(struct uverbs_api *uapi,
 		if (attr->attr.type == UVERBS_ATTR_TYPE_ENUM_IN)
 			method_elm->driver_method |= is_driver;
 
+		/*
+		 * Like other uobject based things we only support a single
+		 * uobject being NEW'd or DESTROY'd
+		 */
+		if (attr->attr.type == UVERBS_ATTR_TYPE_IDRS_ARRAY) {
+			u8 access = attr->attr.u2.objs_arr.access;
+
+			if (WARN_ON(access == UVERBS_ACCESS_NEW ||
+				    access == UVERBS_ACCESS_DESTROY))
+				return -EINVAL;
+		}
+
 		attr_slot =
 			uapi_add_elm(uapi, method_key | uapi_key_attr(attr->id),
 				     sizeof(*attr_slot));

include/rdma/uverbs_ioctl.h

@@ -52,6 +52,7 @@ enum uverbs_attr_type {
 	UVERBS_ATTR_TYPE_IDR,
 	UVERBS_ATTR_TYPE_FD,
 	UVERBS_ATTR_TYPE_ENUM_IN,
+	UVERBS_ATTR_TYPE_IDRS_ARRAY,
 };
 
 enum uverbs_obj_access {
@@ -101,7 +102,7 @@ struct uverbs_attr_spec {
 		} enum_def;
 	} u;
 
-	/* This weird split of the enum lets us remove some padding */
+	/* This weird split lets us remove some padding */
 	union {
 		struct {
 			/*
@@ -111,6 +112,17 @@ struct uverbs_attr_spec {
 			 */
 			const struct uverbs_attr_spec *ids;
 		} enum_def;
+
+		struct {
+			/*
+			 * higher bits mean the namespace and lower bits mean
+			 * the type id within the namespace.
+			 */
+			u16				obj_type;
+			u16				min_len;
+			u16				max_len;
+			u8				access;
+		} objs_arr;
 	} u2;
 };
 
@@ -251,6 +263,11 @@ static inline __attribute_const__ u32 uapi_bkey_attr(u32 attr_key)
 	return attr_key - 1;
 }
 
+static inline __attribute_const__ u32 uapi_bkey_to_key_attr(u32 attr_bkey)
+{
+	return attr_bkey + 1;
+}
+
 /*
  * =======================================
  *	Verbs definitions
@@ -323,6 +340,27 @@ struct uverbs_object_tree_def {
 #define UA_MANDATORY .mandatory = 1
 #define UA_OPTIONAL .mandatory = 0
 
+/*
+ * min_len must be bigger than 0 and _max_len must be smaller than 4095.  Only
+ * READ\WRITE accesses are supported.
+ */
+#define UVERBS_ATTR_IDRS_ARR(_attr_id, _idr_type, _access, _min_len, _max_len, \
+			     ...)                                              \
+	(&(const struct uverbs_attr_def){                                      \
+		.id = (_attr_id) +                                             \
+		      BUILD_BUG_ON_ZERO((_min_len) == 0 ||                     \
+					(_max_len) >                           \
+						PAGE_SIZE / sizeof(void *) ||  \
+					(_min_len) > (_max_len) ||             \
+					(_access) == UVERBS_ACCESS_NEW ||      \
+					(_access) == UVERBS_ACCESS_DESTROY),   \
+		.attr = { .type = UVERBS_ATTR_TYPE_IDRS_ARRAY,                 \
+			  .u2.objs_arr.obj_type = _idr_type,                   \
+			  .u2.objs_arr.access = _access,                       \
+			  .u2.objs_arr.min_len = _min_len,                     \
+			  .u2.objs_arr.max_len = _max_len,                     \
+			  __VA_ARGS__ } })
+
 #define UVERBS_ATTR_IDR(_attr_id, _idr_type, _access, ...)                     \
 	(&(const struct uverbs_attr_def){                                      \
 		.id = _attr_id,                                                \
@@ -440,10 +478,16 @@ struct uverbs_obj_attr {
 	const struct uverbs_api_attr	*attr_elm;
 };
 
+struct uverbs_objs_arr_attr {
+	struct ib_uobject **uobjects;
+	u16 len;
+};
+
 struct uverbs_attr {
 	union {
 		struct uverbs_ptr_attr	ptr_attr;
 		struct uverbs_obj_attr	obj_attr;
+		struct uverbs_objs_arr_attr objs_arr_attr;
 	};
 };
 
@@ -516,6 +560,31 @@ uverbs_attr_get_len(const struct uverbs_attr_bundle *attrs_bundle, u16 idx)
 	return attr->ptr_attr.len;
 }
 
+/**
+ * uverbs_attr_get_uobjs_arr() - Provides array's properties for attribute for
+ * UVERBS_ATTR_TYPE_IDRS_ARRAY.
+ * @arr: Returned pointer to array of pointers for uobjects or NULL if
+ *       the attribute isn't provided.
+ *
+ * Return: The array length or 0 if no attribute was provided.
+ */
+static inline int uverbs_attr_get_uobjs_arr(
+	const struct uverbs_attr_bundle *attrs_bundle, u16 attr_idx,
+	struct ib_uobject ***arr)
+{
+	const struct uverbs_attr *attr =
+			uverbs_attr_get(attrs_bundle, attr_idx);
+
+	if (IS_ERR(attr)) {
+		*arr = NULL;
+		return 0;
+	}
+
+	*arr = attr->objs_arr_attr.uobjects;
+
+	return attr->objs_arr_attr.len;
+}
+
 static inline bool uverbs_attr_ptr_is_inline(const struct uverbs_attr *attr)
 {
 	return attr->ptr_attr.len <= sizeof(attr->ptr_attr.data);

include/uapi/rdma/rdma_user_ioctl_cmds.h

@@ -53,7 +53,7 @@ enum {
 
 struct ib_uverbs_attr {
 	__u16 attr_id;		/* command specific type attribute */
-	__u16 len;		/* only for pointers */
+	__u16 len;		/* only for pointers and IDRs array */
 	__u16 flags;		/* combination of UVERBS_ATTR_F_XXXX */
 	union {
 		struct {
@@ -63,7 +63,10 @@ struct ib_uverbs_attr {
 		__u16 reserved;
 	} attr_data;
 	union {
-		/* Used by PTR_IN/OUT, ENUM_IN and IDR */
+		/*
+		 * ptr to command, inline data, idr/fd or
+		 * ptr to __u32 array of IDRs
+		 */
 		__aligned_u64 data;
 		/* Used by FD_IN and FD_OUT */
 		__s64 data_s64;