[dpdk-dev] [PATCH] pipeline: remove unreachable branch

[dpdk-dev] [PATCH] pipeline: remove unreachable branch

[David Marchand]

A previous change blamed it on compiler/ASan, while this is a real
(yet minor) issue.

This return -EINVAL is never reached since we test all combinations of
fidx and fcin booleans.
All branches end up with a return 0, factorize them.

Fixes: 84f5ac9418ea ("pipeline: fix build with ASan")
Fixes: f38913b7fb8e ("pipeline: add meter array to SWX")

Signed-off-by: David Marchand <david.marchand@redhat.com>
---
---
 lib/pipeline/rte_swx_pipeline.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/lib/pipeline/rte_swx_pipeline.c b/lib/pipeline/rte_swx_pipeline.c
index 1afaffefd4..0bdda7e0b3 100644
--- a/lib/pipeline/rte_swx_pipeline.c
+++ b/lib/pipeline/rte_swx_pipeline.c
@@ -4539,8 +4539,6 @@ instr_meter_translate(struct rte_swx_pipeline *p,
 		instr->meter.color_out.struct_id = (uint8_t)color_out_struct_id;
 		instr->meter.color_out.n_bits = fcout->n_bits;
 		instr->meter.color_out.offset = fcout->offset / 8;
-
-		return 0;
 	}
 
 	/* index = HMEFT, length = HMEFT, color_in = I, color_out = MEF. */
@@ -4575,8 +4573,6 @@ instr_meter_translate(struct rte_swx_pipeline *p,
 		instr->meter.color_out.struct_id = (uint8_t)color_out_struct_id;
 		instr->meter.color_out.n_bits = fcout->n_bits;
 		instr->meter.color_out.offset = fcout->offset / 8;
-
-		return 0;
 	}
 
 	/* index = I, length = HMEFT, color_in = MEFT, color_out = MEF. */
@@ -4607,8 +4603,6 @@ instr_meter_translate(struct rte_swx_pipeline *p,
 		instr->meter.color_out.struct_id = (uint8_t)color_out_struct_id;
 		instr->meter.color_out.n_bits = fcout->n_bits;
 		instr->meter.color_out.offset = fcout->offset / 8;
-
-		return 0;
 	}
 
 	/* index = I, length = HMEFT, color_in = I, color_out = MEF. */
@@ -4638,11 +4632,9 @@ instr_meter_translate(struct rte_swx_pipeline *p,
 		instr->meter.color_out.struct_id = (uint8_t)color_out_struct_id;
 		instr->meter.color_out.n_bits = fcout->n_bits;
 		instr->meter.color_out.offset = fcout->offset / 8;
-
-		return 0;
 	}
 
-	return -EINVAL;
+	return 0;
 }
 
 static inline void
-- 
2.23.0

Re: [dpdk-dev] [PATCH] pipeline: remove unreachable branch

[Dumitrescu, Cristian]

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Wednesday, November 3, 2021 6:57 AM
> To: dev@dpdk.org
> Cc: Dumitrescu, Cristian <cristian.dumitrescu@intel.com>; Lin, Xueqin
> <xueqin.lin@intel.com>; Peng, ZhihongX <zhihongx.peng@intel.com>
> Subject: [PATCH] pipeline: remove unreachable branch
> 
> A previous change blamed it on compiler/ASan, while this is a real
> (yet minor) issue.
> 
> This return -EINVAL is never reached since we test all combinations of
> fidx and fcin booleans.
> All branches end up with a return 0, factorize them.
> 
> Fixes: 84f5ac9418ea ("pipeline: fix build with ASan")
> Fixes: f38913b7fb8e ("pipeline: add meter array to SWX")
> 
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
> ---
>  lib/pipeline/rte_swx_pipeline.c | 10 +---------
>  1 file changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/lib/pipeline/rte_swx_pipeline.c b/lib/pipeline/rte_swx_pipeline.c
> index 1afaffefd4..0bdda7e0b3 100644
> --- a/lib/pipeline/rte_swx_pipeline.c
> +++ b/lib/pipeline/rte_swx_pipeline.c
> @@ -4539,8 +4539,6 @@ instr_meter_translate(struct rte_swx_pipeline *p,
>  		instr->meter.color_out.struct_id =
> (uint8_t)color_out_struct_id;
>  		instr->meter.color_out.n_bits = fcout->n_bits;
>  		instr->meter.color_out.offset = fcout->offset / 8;
> -
> -		return 0;
>  	}
> 
>  	/* index = HMEFT, length = HMEFT, color_in = I, color_out = MEF. */
> @@ -4575,8 +4573,6 @@ instr_meter_translate(struct rte_swx_pipeline *p,
>  		instr->meter.color_out.struct_id =
> (uint8_t)color_out_struct_id;
>  		instr->meter.color_out.n_bits = fcout->n_bits;
>  		instr->meter.color_out.offset = fcout->offset / 8;
> -
> -		return 0;
>  	}
> 
>  	/* index = I, length = HMEFT, color_in = MEFT, color_out = MEF. */
> @@ -4607,8 +4603,6 @@ instr_meter_translate(struct rte_swx_pipeline *p,
>  		instr->meter.color_out.struct_id =
> (uint8_t)color_out_struct_id;
>  		instr->meter.color_out.n_bits = fcout->n_bits;
>  		instr->meter.color_out.offset = fcout->offset / 8;
> -
> -		return 0;
>  	}
> 
>  	/* index = I, length = HMEFT, color_in = I, color_out = MEF. */
> @@ -4638,11 +4632,9 @@ instr_meter_translate(struct rte_swx_pipeline *p,
>  		instr->meter.color_out.struct_id =
> (uint8_t)color_out_struct_id;
>  		instr->meter.color_out.n_bits = fcout->n_bits;
>  		instr->meter.color_out.offset = fcout->offset / 8;
> -
> -		return 0;
>  	}
> 
> -	return -EINVAL;
> +	return 0;
>  }
> 
>  static inline void
> --
> 2.23.0

This is a great idea, thanks David!

I think it is a good compromise between keeping Coverity happy and preserving the code structure and readability, so

Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>

Re: [dpdk-dev] [PATCH] pipeline: remove unreachable branch

[Thomas Monjalon]

> > A previous change blamed it on compiler/ASan, while this is a real
> > (yet minor) issue.
> > 
> > This return -EINVAL is never reached since we test all combinations of
> > fidx and fcin booleans.
> > All branches end up with a return 0, factorize them.
> > 
> > Fixes: 84f5ac9418ea ("pipeline: fix build with ASan")
> > Fixes: f38913b7fb8e ("pipeline: add meter array to SWX")
> > 
> > Signed-off-by: David Marchand <david.marchand@redhat.com>
> 
> Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>

Applied, thanks