RDMA/uverbs: Make write() handlers return 0 on success

Currently they return the command length, while all other handlers return
0. This makes the write path closer to the write_ex and ioctl path.
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>

drivers/infiniband/core/rdma_core.c

@@ -245,13 +245,11 @@ struct ib_uobject *__uobj_get_destroy(const struct uverbs_api_object *obj,
 }
 
 /*
- * Does both uobj_get_destroy() and uobj_put_destroy().  Returns success_res
- * on success (negative errno on failure). For use by callers that do not need
- * the uobj.
+ * Does both uobj_get_destroy() and uobj_put_destroy().  Returns 0 on success
+ * (negative errno on failure). For use by callers that do not need the uobj.
  */
 int __uobj_perform_destroy(const struct uverbs_api_object *obj, u32 id,
-			   const struct uverbs_attr_bundle *attrs,
-			   int success_res)
+			   const struct uverbs_attr_bundle *attrs)
 {
 	struct ib_uobject *uobj;
 
@@ -260,7 +258,7 @@ int __uobj_perform_destroy(const struct uverbs_api_object *obj, u32 id,
 		return PTR_ERR(uobj);
 
 	rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_WRITE);
-	return success_res;
+	return 0;
 }
 
 /* alloc_uobj must be undone by uverbs_destroy_uobject() */

drivers/infiniband/core/rdma_core.h

@@ -137,8 +137,8 @@ struct uverbs_api_ioctl_method {
 };
 
 struct uverbs_api_write_method {
-	ssize_t (*handler)(struct uverbs_attr_bundle *attrs,
-			   const char __user *buf, int in_len, int out_len);
+	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);
 	u8 disabled:1;

drivers/infiniband/core/uverbs_main.c

@@ -688,11 +688,10 @@ static ssize_t ib_uverbs_write(struct file *filp, const char __user *buf,
 					ex_hdr.provider_out_words * 8);
 
 		ret = method_elm->handler_ex(&bundle, &ucore, &uhw);
-		ret = (ret) ? : count;
 	}
 
 	srcu_read_unlock(&file->device->disassociate_srcu, srcu_key);
-	return ret;
+	return (ret) ? : count;
 }
 
 static int ib_uverbs_mmap(struct file *filp, struct vm_area_struct *vma)

drivers/infiniband/core/uverbs_uapi.c

@@ -8,9 +8,8 @@
 #include "rdma_core.h"
 #include "uverbs.h"
 
-static ssize_t ib_uverbs_notsupp(struct uverbs_attr_bundle *attrs,
-				 const char __user *buf, int in_len,
-				 int out_len)
+static int ib_uverbs_notsupp(struct uverbs_attr_bundle *attrs,
+			     const char __user *buf, int in_len, int out_len)
 {
 	return -EOPNOTSUPP;
 }

include/rdma/uverbs_ioctl.h

@@ -368,9 +368,9 @@ struct uapi_definition {
 
 	union {
 		bool (*func_is_supported)(struct ib_device *device);
-		ssize_t (*func_write)(struct uverbs_attr_bundle *attrs,
-				      const char __user *buf, int in_len,
-				      int out_len);
+		int (*func_write)(struct uverbs_attr_bundle *attrs,
+				  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);

include/rdma/uverbs_std_types.h

@@ -72,11 +72,10 @@ static inline void *_uobj_get_obj_read(struct ib_uobject *uobj)
 				_uobj_check_id(_id), UVERBS_LOOKUP_WRITE)
 
 int __uobj_perform_destroy(const struct uverbs_api_object *obj, u32 id,
-			   const struct uverbs_attr_bundle *attrs,
-			   int success_res);
-#define uobj_perform_destroy(_type, _id, _attrs, _success_res)                 \
+			   const struct uverbs_attr_bundle *attrs);
+#define uobj_perform_destroy(_type, _id, _attrs)                               \
 	__uobj_perform_destroy(uobj_get_type(_attrs, _type),                   \
-			       _uobj_check_id(_id), _attrs, _success_res)
+			       _uobj_check_id(_id), _attrs)
 
 struct ib_uobject *__uobj_get_destroy(const struct uverbs_api_object *obj,
 				      u32 id,
@@ -104,14 +103,13 @@ static inline void uobj_put_write(struct ib_uobject *uobj)
 	rdma_lookup_put_uobject(uobj, UVERBS_LOOKUP_WRITE);
 }
 
-static inline int __must_check uobj_alloc_commit(struct ib_uobject *uobj,
-						 int success_res)
+static inline int __must_check uobj_alloc_commit(struct ib_uobject *uobj)
 {
 	int ret = rdma_alloc_commit_uobject(uobj);
 
 	if (ret)
 		return ret;
-	return success_res;
+	return 0;
 }
 
 static inline void uobj_alloc_abort(struct ib_uobject *uobj)