IB/uverbs: Remove the ib_uverbs_attr pointer from each attr

Memory in the bundle is valuable, do not waste it holding an 8 byte
pointer for the rare case of writing to a PTR_OUT. We can compute the
pointer by storing a small 1 byte array offset and the base address of the
uattr memory in the bundle private memory.

This also means we can access the kernel's copy of the ib_uverbs_attr, so
drop the copy of flags as well.

Since the uattr base should be private bundle information this also
de-inlines the already too big uverbs_copy_to inline and moves
create_udata into uverbs_ioctl.c so they can see the private struct
definition.

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>

drivers/infiniband/core/uverbs_ioctl.c

@@ -84,7 +84,6 @@ static int uverbs_process_attr(struct bundle_priv *pbundle,
 	spec = &attr_spec_bucket->attrs[attr_id];
 	val_spec = spec;
 	e = &elements[attr_id];
-	e->uattr = uattr_ptr;
 
 	switch (spec->type) {
 	case UVERBS_ATTR_TYPE_ENUM_IN:
@@ -124,8 +123,8 @@ static int uverbs_process_attr(struct bundle_priv *pbundle,
 		    uattr->attr_data.reserved)
 			return -EINVAL;
 
+		e->ptr_attr.uattr_idx = uattr - pbundle->uattrs;
 		e->ptr_attr.len = uattr->len;
-		e->ptr_attr.flags = uattr->flags;
 
 		if (val_spec->alloc_and_copy && !uverbs_attr_ptr_is_inline(e)) {
 			void *p;
@@ -181,7 +180,7 @@ static int uverbs_process_attr(struct bundle_priv *pbundle,
 			s64 id = o_attr->uobject->id;
 
 			/* Copy the allocated id to the user-space */
-			if (put_user(id, &e->uattr->data)) {
+			if (put_user(id, &uattr_ptr->data)) {
 				uverbs_finalize_object(o_attr->uobject,
 						       UVERBS_ACCESS_NEW,
 						       false);
@@ -562,3 +561,65 @@ int uverbs_get_flags32(u32 *to, const struct uverbs_attr_bundle *attrs_bundle,
 	return 0;
 }
 EXPORT_SYMBOL(uverbs_get_flags32);
+
+/*
+ * This is for ease of conversion. The purpose is to convert all drivers to
+ * use uverbs_attr_bundle instead of ib_udata.  Assume attr == 0 is input and
+ * attr == 1 is output.
+ */
+void create_udata(struct uverbs_attr_bundle *bundle, struct ib_udata *udata)
+{
+	struct bundle_priv *pbundle =
+		container_of(bundle, struct bundle_priv, bundle);
+	const struct uverbs_attr *uhw_in =
+		uverbs_attr_get(bundle, UVERBS_ATTR_UHW_IN);
+	const struct uverbs_attr *uhw_out =
+		uverbs_attr_get(bundle, UVERBS_ATTR_UHW_OUT);
+
+	if (!IS_ERR(uhw_in)) {
+		udata->inlen = uhw_in->ptr_attr.len;
+		if (uverbs_attr_ptr_is_inline(uhw_in))
+			udata->inbuf =
+				&pbundle->user_attrs[uhw_in->ptr_attr.uattr_idx]
+					 .data;
+		else
+			udata->inbuf = u64_to_user_ptr(uhw_in->ptr_attr.data);
+	} else {
+		udata->inbuf = NULL;
+		udata->inlen = 0;
+	}
+
+	if (!IS_ERR(uhw_out)) {
+		udata->outbuf = u64_to_user_ptr(uhw_out->ptr_attr.data);
+		udata->outlen = uhw_out->ptr_attr.len;
+	} else {
+		udata->outbuf = NULL;
+		udata->outlen = 0;
+	}
+}
+
+int uverbs_copy_to(const struct uverbs_attr_bundle *bundle, size_t idx,
+		   const void *from, size_t size)
+{
+	struct bundle_priv *pbundle =
+		container_of(bundle, struct bundle_priv, bundle);
+	const struct uverbs_attr *attr = uverbs_attr_get(bundle, idx);
+	u16 flags;
+	size_t min_size;
+
+	if (IS_ERR(attr))
+		return PTR_ERR(attr);
+
+	min_size = min_t(size_t, attr->ptr_attr.len, size);
+	if (copy_to_user(u64_to_user_ptr(attr->ptr_attr.data), from, min_size))
+		return -EFAULT;
+
+	flags = pbundle->uattrs[attr->ptr_attr.uattr_idx].flags |
+		UVERBS_ATTR_F_VALID_OUTPUT;
+	if (put_user(flags,
+		     &pbundle->user_attrs[attr->ptr_attr.uattr_idx].flags))
+		return -EFAULT;
+
+	return 0;
+}
+EXPORT_SYMBOL(uverbs_copy_to);

drivers/infiniband/core/uverbs_std_types.c

@@ -217,38 +217,6 @@ int uverbs_destroy_def_handler(struct ib_uverbs_file *file,
 }
 EXPORT_SYMBOL(uverbs_destroy_def_handler);
 
-void create_udata(struct uverbs_attr_bundle *ctx, struct ib_udata *udata)
-{
-	/*
-	 * This is for ease of conversion. The purpose is to convert all drivers
-	 * to use uverbs_attr_bundle instead of ib_udata.
-	 * Assume attr == 0 is input and attr == 1 is output.
-	 */
-	const struct uverbs_attr *uhw_in =
-		uverbs_attr_get(ctx, UVERBS_ATTR_UHW_IN);
-	const struct uverbs_attr *uhw_out =
-		uverbs_attr_get(ctx, UVERBS_ATTR_UHW_OUT);
-
-	if (!IS_ERR(uhw_in)) {
-		udata->inlen = uhw_in->ptr_attr.len;
-		if (uverbs_attr_ptr_is_inline(uhw_in))
-			udata->inbuf = &uhw_in->uattr->data;
-		else
-			udata->inbuf = u64_to_user_ptr(uhw_in->ptr_attr.data);
-	} else {
-		udata->inbuf = NULL;
-		udata->inlen = 0;
-	}
-
-	if (!IS_ERR(uhw_out)) {
-		udata->outbuf = u64_to_user_ptr(uhw_out->ptr_attr.data);
-		udata->outlen = uhw_out->ptr_attr.len;
-	} else {
-		udata->outbuf = NULL;
-		udata->outlen = 0;
-	}
-}
-
 DECLARE_UVERBS_NAMED_OBJECT(
 	UVERBS_OBJECT_COMP_CHANNEL,
 	UVERBS_TYPE_ALLOC_FD(sizeof(struct ib_uverbs_completion_event_file),

include/rdma/uverbs_ioctl.h

@@ -461,8 +461,7 @@ struct uverbs_ptr_attr {
 		u64 data;
 	};
 	u16		len;
-	/* Combination of bits from enum UVERBS_ATTR_F_XXXX */
-	u16		flags;
+	u16		uattr_idx;
 	u8		enum_id;
 };
 
@@ -471,11 +470,6 @@ struct uverbs_obj_attr {
 };
 
 struct uverbs_attr {
-	/*
-	 * pointer to the user-space given attribute, in order to write the
-	 * new uobject's id or update flags.
-	 */
-	struct ib_uverbs_attr __user	*uattr;
 	union {
 		struct uverbs_ptr_attr	ptr_attr;
 		struct uverbs_obj_attr	obj_attr;
@@ -575,27 +569,6 @@ uverbs_attr_get_len(const struct uverbs_attr_bundle *attrs_bundle, u16 idx)
 	return attr->ptr_attr.len;
 }
 
-static inline int uverbs_copy_to(const struct uverbs_attr_bundle *attrs_bundle,
-				 size_t idx, const void *from, size_t size)
-{
-	const struct uverbs_attr *attr = uverbs_attr_get(attrs_bundle, idx);
-	u16 flags;
-	size_t min_size;
-
-	if (IS_ERR(attr))
-		return PTR_ERR(attr);
-
-	min_size = min_t(size_t, attr->ptr_attr.len, size);
-	if (copy_to_user(u64_to_user_ptr(attr->ptr_attr.data), from, min_size))
-		return -EFAULT;
-
-	flags = attr->ptr_attr.flags | UVERBS_ATTR_F_VALID_OUTPUT;
-	if (put_user(flags, &attr->uattr->flags))
-		return -EFAULT;
-
-	return 0;
-}
-
 static inline bool uverbs_attr_ptr_is_inline(const struct uverbs_attr *attr)
 {
 	return attr->ptr_attr.len <= sizeof(attr->ptr_attr.data);
@@ -676,6 +649,8 @@ 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);
+int uverbs_copy_to(const struct uverbs_attr_bundle *attrs_bundle, size_t idx,
+		   const void *from, size_t size);
 #else
 static inline int
 uverbs_get_flags64(u64 *to, const struct uverbs_attr_bundle *attrs_bundle,
@@ -689,6 +664,11 @@ uverbs_get_flags32(u32 *to, const struct uverbs_attr_bundle *attrs_bundle,
 {
 	return -EINVAL;
 }
+static inline int uverbs_copy_to(const struct uverbs_attr_bundle *attrs_bundle,
+				 size_t idx, const void *from, size_t size)
+{
+	return -EINVAL;
+}
 #endif
 
 /* =================================================