[PATCH] drm/amdkfd: Use logical AND operator (&&) instead of bitwise AND (&) with a bool operand

[PATCH] drm/amdkfd: Use logical AND operator (&&) instead of bitwise AND (&) with a bool operand

[Srinivasan Shanmugam]

Doing a bitwise AND between a bool and an int is generally not a good
idea.  The bool will be promoted to an int with value 0 or 1, the int is
generally regarded as true with a non-zero value, thus ANDing them using
bitwise has the potential to yield an undesired result.

Thus fixes the below:

drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_packet_manager_v9.c:117 pm_map_process_aldebaran() warn: maybe use && instead of &

Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
index 8ee2bedd301a..da83deee45a7 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
@@ -114,7 +114,7 @@ static int pm_map_process_aldebaran(struct packet_manager *pm,
 			packet->tcp_watch_cntl[i] = pdd->watch_points[i];
 
 		packet->bitfields2.single_memops =
-				!!(pdd->process->dbg_flags & KFD_DBG_TRAP_FLAG_SINGLE_MEM_OP);
+				!!(pdd->process->dbg_flags && KFD_DBG_TRAP_FLAG_SINGLE_MEM_OP);
 	}
 
 	packet->sh_mem_config = qpd->sh_mem_config;
-- 
2.34.1

Re: [PATCH] drm/amdkfd: Use logical AND operator (&&) instead of bitwise AND (&) with a bool operand

[Lazar, Lijo]

On 12/21/2023 8:12 AM, Srinivasan Shanmugam wrote:
> Doing a bitwise AND between a bool and an int is generally not a good
> idea.  The bool will be promoted to an int with value 0 or 1, the int is
> generally regarded as true with a non-zero value, thus ANDing them using
> bitwise has the potential to yield an undesired result.
> 
> Thus fixes the below:
> 
> drivers/gpu/drm/amd/amdgpu/../amdkfd/kfd_packet_manager_v9.c:117 pm_map_process_aldebaran() warn: maybe use && instead of &
> 
> Cc: Felix Kuehling <Felix.Kuehling@amd.com>
> Cc: Christian König <christian.koenig@amd.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
> index 8ee2bedd301a..da83deee45a7 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_packet_manager_v9.c
> @@ -114,7 +114,7 @@ static int pm_map_process_aldebaran(struct packet_manager *pm,
>   			packet->tcp_watch_cntl[i] = pdd->watch_points[i];
>   
>   		packet->bitfields2.single_memops =
> -				!!(pdd->process->dbg_flags & KFD_DBG_TRAP_FLAG_SINGLE_MEM_OP);
> +				!!(pdd->process->dbg_flags && KFD_DBG_TRAP_FLAG_SINGLE_MEM_OP);

Logical AND of bool with a known constant doesn't make sense. dbg_flags 
looks to be defined in the wrong way; to process multiple debug flag 
options, better to define as u32.

Thanks,
Lijo

>   	}
>   
>   	packet->sh_mem_config = qpd->sh_mem_config;