* Re: [PATCH] cfg80211: Change an 'else if' into an 'else' in cfg80211_calculate_bitrate_he
2019-03-07 23:57 [PATCH] cfg80211: Change an 'else if' into an 'else' in cfg80211_calculate_bitrate_he Nathan Chancellor
@ 2019-03-08 0:10 ` Nick Desaulniers
2019-03-20 19:10 ` Nathan Chancellor
2019-03-22 14:16 ` Arnd Bergmann
2 siblings, 0 replies; 5+ messages in thread
From: Nick Desaulniers @ 2019-03-08 0:10 UTC (permalink / raw)
To: Nathan Chancellor
Cc: Johannes Berg, linux-wireless, David S. Miller, netdev, LKML,
clang-built-linux
On Thu, Mar 7, 2019 at 3:57 PM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> When building with -Wsometimes-uninitialized, Clang warns:
>
> net/wireless/util.c:1223:11: warning: variable 'result' is used
> uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
>
> Clang can't evaluate at this point that WARN(1, ...) always returns true
> because __ret_warn_on is defined as !!(condition), which isn't
> immediately evaluated as 1. Change this branch to else so that it's
> clear to Clang that we intend to bail out here.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/382
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Thanks for the quick fix!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
> net/wireless/util.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/wireless/util.c b/net/wireless/util.c
> index e4b8db5e81ec..75899b62bdc9 100644
> --- a/net/wireless/util.c
> +++ b/net/wireless/util.c
> @@ -1220,9 +1220,11 @@ static u32 cfg80211_calculate_bitrate_he(struct rate_info *rate)
> else if (rate->bw == RATE_INFO_BW_HE_RU &&
> rate->he_ru_alloc == NL80211_RATE_INFO_HE_RU_ALLOC_26)
> result = rates_26[rate->he_gi];
> - else if (WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> - rate->bw, rate->he_ru_alloc))
> + else {
> + WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> + rate->bw, rate->he_ru_alloc);
> return 0;
> + }
>
> /* now scale to the appropriate MCS */
> tmp = result;
> --
> 2.21.0
>
--
Thanks,
~Nick Desaulniers
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] cfg80211: Change an 'else if' into an 'else' in cfg80211_calculate_bitrate_he
2019-03-07 23:57 [PATCH] cfg80211: Change an 'else if' into an 'else' in cfg80211_calculate_bitrate_he Nathan Chancellor
2019-03-08 0:10 ` Nick Desaulniers
@ 2019-03-20 19:10 ` Nathan Chancellor
2019-03-22 14:16 ` Arnd Bergmann
2 siblings, 0 replies; 5+ messages in thread
From: Nathan Chancellor @ 2019-03-20 19:10 UTC (permalink / raw)
To: Johannes Berg
Cc: linux-wireless, David S. Miller, netdev, linux-kernel,
clang-built-linux, Nick Desaulniers
On Thu, Mar 07, 2019 at 04:57:35PM -0700, Nathan Chancellor wrote:
> When building with -Wsometimes-uninitialized, Clang warns:
>
> net/wireless/util.c:1223:11: warning: variable 'result' is used
> uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
>
> Clang can't evaluate at this point that WARN(1, ...) always returns true
> because __ret_warn_on is defined as !!(condition), which isn't
> immediately evaluated as 1. Change this branch to else so that it's
> clear to Clang that we intend to bail out here.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/382
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> net/wireless/util.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/wireless/util.c b/net/wireless/util.c
> index e4b8db5e81ec..75899b62bdc9 100644
> --- a/net/wireless/util.c
> +++ b/net/wireless/util.c
> @@ -1220,9 +1220,11 @@ static u32 cfg80211_calculate_bitrate_he(struct rate_info *rate)
> else if (rate->bw == RATE_INFO_BW_HE_RU &&
> rate->he_ru_alloc == NL80211_RATE_INFO_HE_RU_ALLOC_26)
> result = rates_26[rate->he_gi];
> - else if (WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> - rate->bw, rate->he_ru_alloc))
> + else {
> + WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> + rate->bw, rate->he_ru_alloc);
> return 0;
> + }
>
> /* now scale to the appropriate MCS */
> tmp = result;
> --
> 2.21.0
>
Gentle ping (if there was a response to this, I didn't receive it). I
know I sent it in the middle of a merge window so I get if it slipped
through the cracks.
Thanks,
Nathan
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] cfg80211: Change an 'else if' into an 'else' in cfg80211_calculate_bitrate_he
2019-03-07 23:57 [PATCH] cfg80211: Change an 'else if' into an 'else' in cfg80211_calculate_bitrate_he Nathan Chancellor
2019-03-08 0:10 ` Nick Desaulniers
2019-03-20 19:10 ` Nathan Chancellor
@ 2019-03-22 14:16 ` Arnd Bergmann
2019-03-26 9:36 ` Simon Horman
2 siblings, 1 reply; 5+ messages in thread
From: Arnd Bergmann @ 2019-03-22 14:16 UTC (permalink / raw)
To: Nathan Chancellor
Cc: Johannes Berg, linux-wireless, David S. Miller, Networking,
Linux Kernel Mailing List, clang-built-linux, Nick Desaulniers
On Fri, Mar 8, 2019 at 12:57 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> When building with -Wsometimes-uninitialized, Clang warns:
>
> net/wireless/util.c:1223:11: warning: variable 'result' is used
> uninitialized whenever 'if' condition is false
> [-Wsometimes-uninitialized]
>
> Clang can't evaluate at this point that WARN(1, ...) always returns true
> because __ret_warn_on is defined as !!(condition), which isn't
> immediately evaluated as 1. Change this branch to else so that it's
> clear to Clang that we intend to bail out here.
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/382
> Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> net/wireless/util.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/net/wireless/util.c b/net/wireless/util.c
> index e4b8db5e81ec..75899b62bdc9 100644
> --- a/net/wireless/util.c
> +++ b/net/wireless/util.c
> @@ -1220,9 +1220,11 @@ static u32 cfg80211_calculate_bitrate_he(struct rate_info *rate)
> else if (rate->bw == RATE_INFO_BW_HE_RU &&
> rate->he_ru_alloc == NL80211_RATE_INFO_HE_RU_ALLOC_26)
> result = rates_26[rate->he_gi];
> - else if (WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> - rate->bw, rate->he_ru_alloc))
> + else {
> + WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> + rate->bw, rate->he_ru_alloc);
> return 0;
> + }
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
I independently came up with the same fix before I saw yours,
the only difference was that I avoided the extra curly braces
using
+ else
+ return !WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
+ rate->bw, rate->he_ru_alloc);
to avoid the mix of bare if() and if() {}
Arnd
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] cfg80211: Change an 'else if' into an 'else' in cfg80211_calculate_bitrate_he
2019-03-22 14:16 ` Arnd Bergmann
@ 2019-03-26 9:36 ` Simon Horman
0 siblings, 0 replies; 5+ messages in thread
From: Simon Horman @ 2019-03-26 9:36 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Nathan Chancellor, Johannes Berg, linux-wireless,
David S. Miller, Networking, Linux Kernel Mailing List,
clang-built-linux, Nick Desaulniers
On Fri, Mar 22, 2019 at 03:16:06PM +0100, Arnd Bergmann wrote:
> On Fri, Mar 8, 2019 at 12:57 AM Nathan Chancellor
> <natechancellor@gmail.com> wrote:
> >
> > When building with -Wsometimes-uninitialized, Clang warns:
> >
> > net/wireless/util.c:1223:11: warning: variable 'result' is used
> > uninitialized whenever 'if' condition is false
> > [-Wsometimes-uninitialized]
> >
> > Clang can't evaluate at this point that WARN(1, ...) always returns true
> > because __ret_warn_on is defined as !!(condition), which isn't
> > immediately evaluated as 1. Change this branch to else so that it's
> > clear to Clang that we intend to bail out here.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/382
> > Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> > ---
> > net/wireless/util.c | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/wireless/util.c b/net/wireless/util.c
> > index e4b8db5e81ec..75899b62bdc9 100644
> > --- a/net/wireless/util.c
> > +++ b/net/wireless/util.c
> > @@ -1220,9 +1220,11 @@ static u32 cfg80211_calculate_bitrate_he(struct rate_info *rate)
> > else if (rate->bw == RATE_INFO_BW_HE_RU &&
> > rate->he_ru_alloc == NL80211_RATE_INFO_HE_RU_ALLOC_26)
> > result = rates_26[rate->he_gi];
> > - else if (WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> > - rate->bw, rate->he_ru_alloc))
> > + else {
> > + WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> > + rate->bw, rate->he_ru_alloc);
> > return 0;
> > + }
>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
>
> I independently came up with the same fix before I saw yours,
> the only difference was that I avoided the extra curly braces
> using
>
> + else
> + return !WARN(1, "invalid HE MCS: bw:%d, ru:%d\n",
> + rate->bw, rate->he_ru_alloc);
>
> to avoid the mix of bare if() and if() {}
Right, shouldn't all arms of the if/else if/else conditional have {}
if any arm has {}.
^ permalink raw reply [flat|nested] 5+ messages in thread