Looks like a bug: operands are different enum types 'ibv_flow_attr_type' and 'ibv_flow_flags'

[Suanming Mou]

Hi Andre,


> -----Original Message-----
> From: Andre Muezerie <andremue at linux.microsoft.com>
> Sent: Wednesday, May 28, 2025 3:33 AM
> To: Dariusz Sosnowski <dsosnowski at nvidia.com>; Slava Ovsiienko
> <viacheslavo at nvidia.com>; Bing Zhao <bingz at nvidia.com>; Ori Kam
> <orika at nvidia.com>; Suanming Mou <suanmingm at nvidia.com>; Matan
> Azrad <matan at nvidia.com>
> Cc: dev at dpdk.org
> Subject: Looks like a bug: operands are different enum types
> 'ibv_flow_attr_type' and 'ibv_flow_flags'
> 
> Hi Folks,
> 
> 
> Compiling with MSCS resulted in the warning below:
> 
> ../drivers/net/mlx5/mlx5_flow_dv.c(19636): warning C5287: operands are
> different enum types 'ibv_flow_attr_type' and 'ibv_flow_flags'; use an explicit
> cast to silence this warning
> 
> It looks like a legit bug. Here is the offending line:
> 
> 	struct mlx5dv_flow_matcher_attr dv_attr = {
> 		.type = IBV_FLOW_ATTR_NORMAL |
> IBV_FLOW_ATTR_FLAGS_EGRESS,
> 
> As the warning states, the constants in the bitwise operation belong to
> different enums, and these enums have overlaping values, which makes the
> bitwise operation very suspicious.
> On top of that, I see that struct mlx5dv_flow_matcher_attr has a field named
> "flags" which accepts values from ibv_flow_flags:
> 
> 	struct mlx5dv_flow_matcher_attr {
> 		enum ibv_flow_attr_type type;
> 		uint32_t flags; /* From enum ibv_flow_flags. */
> 
> Could someone more familiar with the code take a look and make a fix if
> needed? My goal here is just to get the code to compile with MSVC without
> warnings. I can add a cast to remove the warning if this is indeed how the
> code should be, but I don't want to do this unless I get confirmation that this
> would be the right course of action.

Yes, I think you are right. ` IBV_FLOW_ATTR_FLAGS_EGRESS ` should goes to flags.
Thanks for the reporting. 
Will first try to verify how it works even with the incorrect initialization.

> 
> Thanks,
> 
> Andre Muezerie