RDMA/uverbs: Use uverbs_attr_bundle to pass udata for write_ex

The core code needs to compute the udata so we may as well pass it in the
uverbs_attr_bundle instead of on the stack. This converts the simple case
of write_ex() which already has a core calculation.

Also change the write() path to use the attrs for ib_uverbs_init_udata()
instead of on the stack. This lets the write to write_ex compatibility
path continue to follow the lead of the _ex path.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

drivers/infiniband/core/rdma_core.h

@@ -139,7 +139,7 @@ struct uverbs_api_write_method {
 	int (*handler)(struct uverbs_attr_bundle *attrs, const char __user *buf,
 		       int in_len, int out_len);
 	int (*handler_ex)(struct uverbs_attr_bundle *attrs,
-			  struct ib_udata *ucore, struct ib_udata *uhw);
+			  struct ib_udata *ucore);
 	u8 disabled:1;
 	u8 is_ex:1;
 	u8 has_udata:1;

drivers/infiniband/core/uverbs_main.c

@@ -697,7 +697,6 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
 					  hdr.out_words * 4);
 	} else {
 		struct ib_udata ucore;
-		struct ib_udata uhw;
 
 		buf += sizeof(ex_hdr);
 
@@ -705,13 +704,13 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
 					u64_to_user_ptr(ex_hdr.response),
 					hdr.in_words * 8, hdr.out_words * 8);
 
-		ib_uverbs_init_udata_buf_or_null(&uhw,
+		ib_uverbs_init_udata_buf_or_null(&bundle.driver_udata,
 					buf + ucore.inlen,
 					u64_to_user_ptr(ex_hdr.response) + ucore.outlen,
 					ex_hdr.provider_in_words * 8,
 					ex_hdr.provider_out_words * 8);
 
-		ret = method_elm->handler_ex(&bundle, &ucore, &uhw);
+		ret = method_elm->handler_ex(&bundle, &ucore);
 	}
 
 	srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);

drivers/infiniband/core/uverbs_uapi.c

@@ -15,7 +15,7 @@ static int ib_uverbs_notsupp(struct uverbs_attr_bundle *attrs,
 }
 
 static int ib_uverbs_ex_notsupp(struct uverbs_attr_bundle *attrs,
-				struct ib_udata *ucore, struct ib_udata *uhw)
+				struct ib_udata *ucore)
 {
 	return -EOPNOTSUPP;
 }

include/rdma/uverbs_ioctl.h

@@ -375,8 +375,7 @@ struct uapi_definition {
 				  const char __user *buf, int in_len,
 				  int out_len);
 		int (*func_write_ex)(struct uverbs_attr_bundle *attrs,
-				     struct ib_udata *ucore,
-				     struct ib_udata *uhw);
+				     struct ib_udata *ucore);
 		const struct uapi_definition *chain;
 		const struct uverbs_object_def *chain_obj_tree;
 		size_t needs_fn_offset;
@@ -643,6 +642,7 @@ struct uverbs_attr {
 };
 
 struct uverbs_attr_bundle {
+	struct ib_udata driver_udata;
 	struct ib_uverbs_file *ufile;
 	DECLARE_BITMAP(attr_present, UVERBS_API_ATTR_BKEY_LEN);
 	struct uverbs_attr attrs[];