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Groups > linux.kernel > #1739572 > unrolled thread

[PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe()

Started byByungchul Park <byungchul.park@lge.com>
First post2017-09-26 09:00 +0200
Last post2017-09-26 10:40 +0200
Articles 5 — 3 participants

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  [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe() Byungchul Park <byungchul.park@lge.com> - 2017-09-26 09:00 +0200
    Re: [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe() "Huang\, Ying" <ying.huang@intel.com> - 2017-09-26 09:10 +0200
      RE: [PATCH] llist: Put parentheses around parameters of  llist_for_each_entry_safe() 박병철/선임연구원/SW Platform(연)AOT팀(byungchul.park@lge.com)          <byungchul.park@lge.com> - 2017-09-26 10:10 +0200
        Re: [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe() "Huang\, Ying" <ying.huang@intel.com> - 2017-09-26 10:20 +0200
          RE: [PATCH] llist: Put parentheses around parameters of  llist_for_each_entry_safe() 박병철/선임연구원/SW Platform(연)AOT팀(byungchul.park@lge.com)          <byungchul.park@lge.com> - 2017-09-26 10:40 +0200

#1739572 — [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe()

FromByungchul Park <byungchul.park@lge.com>
Date2017-09-26 09:00 +0200
Subject[PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe()
Message-ID<utS0y-18O-23@gated-at.bofh.it>
It would be somewhat safer to put parentheses around parameters of
a macro with parameters. Put it.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
 include/linux/llist.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/linux/llist.h b/include/linux/llist.h
index 1957635..e280b297 100644
--- a/include/linux/llist.h
+++ b/include/linux/llist.h
@@ -183,10 +183,10 @@ static inline void init_llist_head(struct llist_head *list)
  * reverse the order by yourself before traversing.
  */
 #define llist_for_each_entry_safe(pos, n, node, member)			       \
-	for (pos = llist_entry((node), typeof(*pos), member);		       \
+	for ((pos) = llist_entry((node), typeof(*(pos)), member);		       \
 	     member_address_is_nonnull(pos, member) &&			       \
-	        (n = llist_entry(pos->member.next, typeof(*n), member), true); \
-	     pos = n)
+	        ((n) = llist_entry((pos)->member.next, typeof(*(n)), member), true); \
+	     (pos) = (n))
 
 /**
  * llist_empty - tests whether a lock-less list is empty
-- 
1.9.1

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#1739583

From"Huang\, Ying" <ying.huang@intel.com>
Date2017-09-26 09:10 +0200
Message-ID<utSae-1rM-13@gated-at.bofh.it>
In reply to#1739572
Hi, Byungchul,

Byungchul Park <byungchul.park@lge.com> writes:

> It would be somewhat safer to put parentheses around parameters of
> a macro with parameters. Put it.
>
> Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> ---
>  include/linux/llist.h | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/llist.h b/include/linux/llist.h
> index 1957635..e280b297 100644
> --- a/include/linux/llist.h
> +++ b/include/linux/llist.h
> @@ -183,10 +183,10 @@ static inline void init_llist_head(struct llist_head *list)
>   * reverse the order by yourself before traversing.
>   */
>  #define llist_for_each_entry_safe(pos, n, node, member)			       \
> -	for (pos = llist_entry((node), typeof(*pos), member);		       \
> +	for ((pos) = llist_entry((node), typeof(*(pos)), member);		       \
>  	     member_address_is_nonnull(pos, member) &&			       \
> -	        (n = llist_entry(pos->member.next, typeof(*n), member), true); \
> -	     pos = n)
> +	        ((n) = llist_entry((pos)->member.next, typeof(*(n)), member), true); \
> +	     (pos) = (n))
>  
>  /**
>   * llist_empty - tests whether a lock-less list is empty

The original code follows the style of list_for_each_entry_safe().  The
parameters "pos" and "n" must be variable.  Because list_xxx family
functions work well so far, I think we needn't to change it too.

Best Regards,
Huang, Ying

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#1739658 — RE: [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe()

From박병철/선임연구원/SW Platform(연)AOT팀(byungchul.park@lge.com) <byungchul.park@lge.com>
Date2017-09-26 10:10 +0200
SubjectRE: [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe()
Message-ID<utT6j-26b-31@gated-at.bofh.it>
In reply to#1739583
> -----Original Message-----
> From: Huang, Ying [mailto:ying.huang@intel.com]
> Sent: Tuesday, September 26, 2017 4:02 PM
> To: Byungchul Park
> Cc: peterz@infradead.org; mingo@kernel.org; linux-kernel@vger.kernel.org;
> kernel-team@lge.com; ying.huang@intel.com
> Subject: Re: [PATCH] llist: Put parentheses around parameters of
> llist_for_each_entry_safe()
> 
> Hi, Byungchul,
> 
> Byungchul Park <byungchul.park@lge.com> writes:
> 
> > It would be somewhat safer to put parentheses around parameters of
> > a macro with parameters. Put it.
> >
> > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> > ---
> >  include/linux/llist.h | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> > index 1957635..e280b297 100644
> > --- a/include/linux/llist.h
> > +++ b/include/linux/llist.h
> > @@ -183,10 +183,10 @@ static inline void init_llist_head(struct llist_head *list)
> >   * reverse the order by yourself before traversing.
> >   */
> >  #define llist_for_each_entry_safe(pos, n, node, member)
> 	       \
> > -	for (pos = llist_entry((node), typeof(*pos), member);		       \
> > +	for ((pos) = llist_entry((node), typeof(*(pos)), member);		       \
> >  	     member_address_is_nonnull(pos, member) &&
> 	       \
> > -	        (n = llist_entry(pos->member.next, typeof(*n), member), true); \
> > -	     pos = n)
> > +	        ((n) = llist_entry((pos)->member.next, typeof(*(n)), member), true);
> \
> > +	     (pos) = (n))
> >
> >  /**
> >   * llist_empty - tests whether a lock-less list is empty
> 
> The original code follows the style of list_for_each_entry_safe().  The

Hello Huang,

I don’t see what you say here exactly, but let me note that all llist macros
are safe except the llist_for_each_entry_safe().

> parameters "pos" and "n" must be variable.  Because list_xxx family
> functions work well so far, I think we needn't to change it too.

I see. I don't want to argue much wrt such a trivial thing but I think
it would be better to fix it since the fix is fairly simple and clear. 
However, it's ok if the fix introduces a bad thing at least.

> Best Regards,
> Huang, Ying

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#1739661

From"Huang\, Ying" <ying.huang@intel.com>
Date2017-09-26 10:20 +0200
Message-ID<utTfY-29X-17@gated-at.bofh.it>
In reply to#1739658
"박병철/선임연구원/SW Platform(연)AOT팀(byungchul.park@lge.com)"
<byungchul.park@lge.com> writes:

>> -----Original Message-----
>> From: Huang, Ying [mailto:ying.huang@intel.com]
>> Sent: Tuesday, September 26, 2017 4:02 PM
>> To: Byungchul Park
>> Cc: peterz@infradead.org; mingo@kernel.org; linux-kernel@vger.kernel.org;
>> kernel-team@lge.com; ying.huang@intel.com
>> Subject: Re: [PATCH] llist: Put parentheses around parameters of
>> llist_for_each_entry_safe()
>> 
>> Hi, Byungchul,
>> 
>> Byungchul Park <byungchul.park@lge.com> writes:
>> 
>> > It would be somewhat safer to put parentheses around parameters of
>> > a macro with parameters. Put it.
>> >
>> > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
>> > ---
>> >  include/linux/llist.h | 6 +++---
>> >  1 file changed, 3 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/include/linux/llist.h b/include/linux/llist.h
>> > index 1957635..e280b297 100644
>> > --- a/include/linux/llist.h
>> > +++ b/include/linux/llist.h
>> > @@ -183,10 +183,10 @@ static inline void init_llist_head(struct llist_head *list)
>> >   * reverse the order by yourself before traversing.
>> >   */
>> >  #define llist_for_each_entry_safe(pos, n, node, member)
>> 	       \
>> > -	for (pos = llist_entry((node), typeof(*pos), member);		       \
>> > +	for ((pos) = llist_entry((node), typeof(*(pos)), member);		       \
>> >  	     member_address_is_nonnull(pos, member) &&
>> 	       \
>> > -	        (n = llist_entry(pos->member.next, typeof(*n), member), true); \
>> > -	     pos = n)
>> > +	        ((n) = llist_entry((pos)->member.next, typeof(*(n)), member), true);
>> \
>> > +	     (pos) = (n))
>> >
>> >  /**
>> >   * llist_empty - tests whether a lock-less list is empty
>> 
>> The original code follows the style of list_for_each_entry_safe().  The
>
> Hello Huang,
>
> I don’t see what you say here exactly, but let me note that all llist macros
> are safe except the llist_for_each_entry_safe().
>
>> parameters "pos" and "n" must be variable.  Because list_xxx family
>> functions work well so far, I think we needn't to change it too.
>
> I see. I don't want to argue much wrt such a trivial thing but I think
> it would be better to fix it since the fix is fairly simple and clear. 
> However, it's ok if the fix introduces a bad thing at least.

Yes, it's simple.  But I don't think it helps too.  Considering that
list family functions with same style have no issues.

Best Regards,
Huang, Ying

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#1739675 — RE: [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe()

From박병철/선임연구원/SW Platform(연)AOT팀(byungchul.park@lge.com) <byungchul.park@lge.com>
Date2017-09-26 10:40 +0200
SubjectRE: [PATCH] llist: Put parentheses around parameters of llist_for_each_entry_safe()
Message-ID<utTzk-2jm-21@gated-at.bofh.it>
In reply to#1739661
> -----Original Message-----
> From: Huang, Ying [mailto:ying.huang@intel.com]
> Sent: Tuesday, September 26, 2017 5:14 PM
> To: 박병철/선임연구원/SW Platform(연)AOT팀(byungchul.park@lge.com)
> Cc: Huang, Ying; peterz@infradead.org; mingo@kernel.org; linux-
> kernel@vger.kernel.org; kernel-team@lge.com
> Subject: Re: [PATCH] llist: Put parentheses around parameters of
> llist_for_each_entry_safe()
> 
> "박병철/선임연구원/SW Platform(연)AOT팀(byungchul.park@lge.com)"
> <byungchul.park@lge.com> writes:
> 
> >> -----Original Message-----
> >> From: Huang, Ying [mailto:ying.huang@intel.com]
> >> Sent: Tuesday, September 26, 2017 4:02 PM
> >> To: Byungchul Park
> >> Cc: peterz@infradead.org; mingo@kernel.org; linux-kernel@vger.kernel.org;
> >> kernel-team@lge.com; ying.huang@intel.com
> >> Subject: Re: [PATCH] llist: Put parentheses around parameters of
> >> llist_for_each_entry_safe()
> >>
> >> Hi, Byungchul,
> >>
> >> Byungchul Park <byungchul.park@lge.com> writes:
> >>
> >> > It would be somewhat safer to put parentheses around parameters of
> >> > a macro with parameters. Put it.
> >> >
> >> > Signed-off-by: Byungchul Park <byungchul.park@lge.com>
> >> > ---
> >> >  include/linux/llist.h | 6 +++---
> >> >  1 file changed, 3 insertions(+), 3 deletions(-)
> >> >
> >> > diff --git a/include/linux/llist.h b/include/linux/llist.h
> >> > index 1957635..e280b297 100644
> >> > --- a/include/linux/llist.h
> >> > +++ b/include/linux/llist.h
> >> > @@ -183,10 +183,10 @@ static inline void init_llist_head(struct llist_head
> *list)
> >> >   * reverse the order by yourself before traversing.
> >> >   */
> >> >  #define llist_for_each_entry_safe(pos, n, node, member)
> >> 	       \
> >> > -	for (pos = llist_entry((node), typeof(*pos), member);		       \
> >> > +	for ((pos) = llist_entry((node), typeof(*(pos)), member);		       \
> >> >  	     member_address_is_nonnull(pos, member) &&
> >> 	       \
> >> > -	        (n = llist_entry(pos->member.next, typeof(*n), member), true); \
> >> > -	     pos = n)
> >> > +	        ((n) = llist_entry((pos)->member.next, typeof(*(n)), member), true);
> >> \
> >> > +	     (pos) = (n))
> >> >
> >> >  /**
> >> >   * llist_empty - tests whether a lock-less list is empty
> >>
> >> The original code follows the style of list_for_each_entry_safe().  The
> >
> > Hello Huang,
> >
> > I don’t see what you say here exactly, but let me note that all llist macros
> > are safe except the llist_for_each_entry_safe().
> >
> >> parameters "pos" and "n" must be variable.  Because list_xxx family
> >> functions work well so far, I think we needn't to change it too.
> >
> > I see. I don't want to argue much wrt such a trivial thing but I think
> > it would be better to fix it since the fix is fairly simple and clear.
> > However, it's ok if the fix introduces a bad thing at least.
> 
> Yes, it's simple.  But I don't think it helps too.  Considering that
> list family functions with same style have no issues.

In addition, making all the llist macros implementation consistent is
also meaningful, isn't it?

Ok.

I think your opinion is right and mine is also meaningful. I will just
follow the majority opinion.

Thank you for giving an opinion.

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