Re: [PATCH] bpf: reduce compiler warnings by adding fallthrough comments

[David Miller]

From: Alexander Alemayhu 
Date: Tue, 14 Feb 2017 00:02:35 +0100

> Fixes the following warnings:
 ...
> Reported-by: David Binderman 
> Signed-off-by: Alexander Alemayhu 

Applied, thank you.

Re: [PATCH] bpf: reduce compiler warnings by adding fallthrough comments

[Alexei Starovoitov]

On Tue, Feb 14, 2017 at 12:18:05AM +0100, Daniel Borkmann wrote:
> >kernel/bpf/verifier.c:2019:24: warning: this statement may fall through 
> >[-Wimplicit-fallthrough=]
> >false_reg->min_value = 0;
> >~^~~
> >
> >Reported-by: David Binderman 
> >Signed-off-by: Alexander Alemayhu 
> 
> These fall-through comments are fine for net-next tree.
> 
> Acked-by: Daniel Borkmann 

lgtm as well
Acked-by: Alexei Starovoitov 

Re: [PATCH] bpf: reduce compiler warnings by adding fallthrough comments

[Daniel Borkmann]

On 02/14/2017 12:02 AM, Alexander Alemayhu wrote:

Fixes the following warnings:

kernel/bpf/verifier.c: In function ‘may_access_direct_pkt_data’:
kernel/bpf/verifier.c:702:6: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
if (t == BPF_WRITE)
   ^
kernel/bpf/verifier.c:704:2: note: here
   case BPF_PROG_TYPE_SCHED_CLS:
   ^~~~
kernel/bpf/verifier.c: In function ‘reg_set_min_max_inv’:
kernel/bpf/verifier.c:2057:23: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
true_reg->min_value = 0;
^~~
kernel/bpf/verifier.c:2058:2: note: here
   case BPF_JSGT:
   ^~~~
kernel/bpf/verifier.c:2068:23: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
true_reg->min_value = 0;
^~~
kernel/bpf/verifier.c:2069:2: note: here
   case BPF_JSGE:
   ^~~~
kernel/bpf/verifier.c: In function ‘reg_set_min_max’:
kernel/bpf/verifier.c:2009:24: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
false_reg->min_value = 0;
~^~~
kernel/bpf/verifier.c:2010:2: note: here
   case BPF_JSGT:
   ^~~~
kernel/bpf/verifier.c:2019:24: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
false_reg->min_value = 0;
~^~~
kernel/bpf/verifier.c:2020:2: note: here
   case BPF_JSGE:
   ^~~~

Reported-by: David Binderman 
Signed-off-by: Alexander Alemayhu 


These fall-through comments are fine for net-next tree.

Acked-by: Daniel Borkmann 

[PATCH] bpf: reduce compiler warnings by adding fallthrough comments

[Alexander Alemayhu]

Fixes the following warnings:

kernel/bpf/verifier.c: In function ‘may_access_direct_pkt_data’:
kernel/bpf/verifier.c:702:6: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
   if (t == BPF_WRITE)
  ^
kernel/bpf/verifier.c:704:2: note: here
  case BPF_PROG_TYPE_SCHED_CLS:
  ^~~~
kernel/bpf/verifier.c: In function ‘reg_set_min_max_inv’:
kernel/bpf/verifier.c:2057:23: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
   true_reg->min_value = 0;
   ^~~
kernel/bpf/verifier.c:2058:2: note: here
  case BPF_JSGT:
  ^~~~
kernel/bpf/verifier.c:2068:23: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
   true_reg->min_value = 0;
   ^~~
kernel/bpf/verifier.c:2069:2: note: here
  case BPF_JSGE:
  ^~~~
kernel/bpf/verifier.c: In function ‘reg_set_min_max’:
kernel/bpf/verifier.c:2009:24: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
   false_reg->min_value = 0;
   ~^~~
kernel/bpf/verifier.c:2010:2: note: here
  case BPF_JSGT:
  ^~~~
kernel/bpf/verifier.c:2019:24: warning: this statement may fall through 
[-Wimplicit-fallthrough=]
   false_reg->min_value = 0;
   ~^~~
kernel/bpf/verifier.c:2020:2: note: here
  case BPF_JSGE:
  ^~~~

Reported-by: David Binderman 
Signed-off-by: Alexander Alemayhu 
---
Using gcc (GCC) 7.0.1 20170204 (Red Hat 7.0.1-0.6)

 kernel/bpf/verifier.c | 5 +
 1 file changed, 5 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1a754e5d2695..d2bded2b250c 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -701,6 +701,7 @@ static bool may_access_direct_pkt_data(struct 
bpf_verifier_env *env,
/* dst_input() and dst_output() can't write for now */
if (t == BPF_WRITE)
return false;
+   /* fallthrough */
case BPF_PROG_TYPE_SCHED_CLS:
case BPF_PROG_TYPE_SCHED_ACT:
case BPF_PROG_TYPE_XDP:
@@ -2007,6 +2008,7 @@ static void reg_set_min_max(struct bpf_reg_state 
*true_reg,
case BPF_JGT:
/* Unsigned comparison, the minimum value is 0. */
false_reg->min_value = 0;
+   /* fallthrough */
case BPF_JSGT:
/* If this is false then we know the maximum val is val,
 * otherwise we know the min val is val+1.
@@ -2017,6 +2019,7 @@ static void reg_set_min_max(struct bpf_reg_state 
*true_reg,
case BPF_JGE:
/* Unsigned comparison, the minimum value is 0. */
false_reg->min_value = 0;
+   /* fallthrough */
case BPF_JSGE:
/* If this is false then we know the maximum value is val - 1,
 * otherwise we know the mimimum value is val.
@@ -2055,6 +2058,7 @@ static void reg_set_min_max_inv(struct bpf_reg_state 
*true_reg,
case BPF_JGT:
/* Unsigned comparison, the minimum value is 0. */
true_reg->min_value = 0;
+   /* fallthrough */
case BPF_JSGT:
/*
 * If this is false, then the val is <= the register, if it is
@@ -2066,6 +2070,7 @@ static void reg_set_min_max_inv(struct bpf_reg_state 
*true_reg,
case BPF_JGE:
/* Unsigned comparison, the minimum value is 0. */
true_reg->min_value = 0;
+   /* fallthrough */
case BPF_JSGE:
/* If this is false then constant < register, if it is true then
 * the register < constant.
-- 
2.11.1