[v1] xen: notifier: refine 'notifier_head', use 'list_head' directly

[Xen-devel] [PATCH RESEND] xen: notifier: refine 'notifier_head', use 'list_head' directly

Posted by Baodong Chen 4 years, 10 months ago

'notifier_block' can be replaced with 'list_head' when used for
'notifier_head', this make the a little more clear.

Signed-off-by: Baodong Chen <chenbaodong@mxnavi.com>
---
 xen/common/notifier.c      | 12 ++++++------
 xen/include/xen/notifier.h |  7 +++----
 2 files changed, 9 insertions(+), 10 deletions(-)

diff --git a/xen/common/notifier.c b/xen/common/notifier.c
index 34488a8..c7b0669 100644
--- a/xen/common/notifier.c
+++ b/xen/common/notifier.c
@@ -21,10 +21,10 @@
 void __init notifier_chain_register(
     struct notifier_head *nh, struct notifier_block *n)
 {
-    struct list_head *chain = &nh->head.chain;
+    struct list_head *chain = &nh->head;
     struct notifier_block *nb;
 
-    while ( chain->next != &nh->head.chain )
+    while ( chain->next != &nh->head )
     {
         nb = list_entry(chain->next, struct notifier_block, chain);
         if ( n->priority > nb->priority )
@@ -71,16 +71,16 @@ int notifier_call_chain(
 {
     int ret = NOTIFY_DONE;
     struct list_head *cursor;
-    struct notifier_block *nb;
+    struct notifier_block *nb = NULL;
     bool_t reverse = !!(val & NOTIFY_REVERSE);
 
-    cursor = &(pcursor && *pcursor ? *pcursor : &nh->head)->chain;
+    cursor = (pcursor && *pcursor ? &(*pcursor)->chain : &nh->head);
 
     do {
         cursor = reverse ? cursor->prev : cursor->next;
-        nb = list_entry(cursor, struct notifier_block, chain);
-        if ( cursor == &nh->head.chain )
+        if ( cursor == &nh->head )
             break;
+        nb = list_entry(cursor, struct notifier_block, chain);
         ret = nb->notifier_call(nb, val, v);
     } while ( !(ret & NOTIFY_STOP_MASK) );
 
diff --git a/xen/include/xen/notifier.h b/xen/include/xen/notifier.h
index d1ff9b1..2e58bd9 100644
--- a/xen/include/xen/notifier.h
+++ b/xen/include/xen/notifier.h
@@ -29,13 +29,12 @@ struct notifier_block {
 };
 
 struct notifier_head {
-    struct notifier_block head;
+    struct list_head head;
 };
 
-#define NOTIFIER_INIT(name) { .head.chain = LIST_HEAD_INIT(name.head.chain) }
+#define NOTIFIER_HEAD(name)                                                    \
+  struct notifier_head name = {.head = LIST_HEAD_INIT(name.head)}
 
-#define NOTIFIER_HEAD(name) \
-    struct notifier_head name = NOTIFIER_INIT(name)
 
 void notifier_chain_register(
     struct notifier_head *nh, struct notifier_block *nb);
-- 
2.7.4


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Re: [Xen-devel] [PATCH RESEND] xen: notifier: refine 'notifier_head', use 'list_head' directly

Posted by Jan Beulich 4 years, 10 months ago

>>> On 03.06.19 at 03:33, <chenbaodong@mxnavi.com> wrote:
> 'notifier_block' can be replaced with 'list_head' when used for
> 'notifier_head', this make the a little more clear.

I guess you mean "... makes the code a little ..."?

> @@ -71,16 +71,16 @@ int notifier_call_chain(
>  {
>      int ret = NOTIFY_DONE;
>      struct list_head *cursor;
> -    struct notifier_block *nb;
> +    struct notifier_block *nb = NULL;
>      bool_t reverse = !!(val & NOTIFY_REVERSE);
>  
> -    cursor = &(pcursor && *pcursor ? *pcursor : &nh->head)->chain;
> +    cursor = (pcursor && *pcursor ? &(*pcursor)->chain : &nh->head);

The outermost parentheses are now not really needed anymore.

> --- a/xen/include/xen/notifier.h
> +++ b/xen/include/xen/notifier.h
> @@ -29,13 +29,12 @@ struct notifier_block {
>  };
>  
>  struct notifier_head {
> -    struct notifier_block head;
> +    struct list_head head;
>  };
>  
> -#define NOTIFIER_INIT(name) { .head.chain = LIST_HEAD_INIT(name.head.chain) }

Note the blanks immediately inside the figure braces - ...

> +#define NOTIFIER_HEAD(name)                                                    \
> +  struct notifier_head name = {.head = LIST_HEAD_INIT(name.head)}

... please don't break such style aspects, unless you know
it is something that needs fixing (for being in violation of our
style guidelines).

Jan



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Re: [Xen-devel] [PATCH RESEND] xen: notifier: refine 'notifier_head', use 'list_head' directly

Posted by chenbaodong 4 years, 10 months ago

On 6/3/19 17:27, Jan Beulich wrote:
>>>> On 03.06.19 at 03:33, <chenbaodong@mxnavi.com> wrote:
>> 'notifier_block' can be replaced with 'list_head' when used for
>> 'notifier_head', this make the a little more clear.
> I guess you mean "... makes the code a little ..."?
Yes, fixed, see v1.
>> @@ -71,16 +71,16 @@ int notifier_call_chain(
>>   {
>>       int ret = NOTIFY_DONE;
>>       struct list_head *cursor;
>> -    struct notifier_block *nb;
>> +    struct notifier_block *nb = NULL;
>>       bool_t reverse = !!(val & NOTIFY_REVERSE);
>>   
>> -    cursor = &(pcursor && *pcursor ? *pcursor : &nh->head)->chain;
>> +    cursor = (pcursor && *pcursor ? &(*pcursor)->chain : &nh->head);
> The outermost parentheses are now not really needed anymore.
Yes, fixed, see v1.
>
>> --- a/xen/include/xen/notifier.h
>> +++ b/xen/include/xen/notifier.h
>> @@ -29,13 +29,12 @@ struct notifier_block {
>>   };
>>   
>>   struct notifier_head {
>> -    struct notifier_block head;
>> +    struct list_head head;
>>   };
>>   
>> -#define NOTIFIER_INIT(name) { .head.chain = LIST_HEAD_INIT(name.head.chain) }
> Note the blanks immediately inside the figure braces - ...
Yes, fixed, see v1.
>
>> +#define NOTIFIER_HEAD(name)                                                    \
>> +  struct notifier_head name = {.head = LIST_HEAD_INIT(name.head)}
> ... please don't break such style aspects, unless you know
> it is something that needs fixing (for being in violation of our
> style guidelines).
Yes, fixed, see v1.
>
> Jan
>
>
> .
>

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Re: [Xen-devel] [PATCH RESEND] xen: notifier: refine 'notifier_head', use 'list_head' directly

Posted by Jan Beulich 4 years, 10 months ago

>>> On 03.06.19 at 03:33, <chenbaodong@mxnavi.com> wrote:
> 'notifier_block' can be replaced with 'list_head' when used for
> 'notifier_head', this make the a little more clear.
> 
> Signed-off-by: Baodong Chen <chenbaodong@mxnavi.com>

Oh, and also a remark regarding the title: Why "RESEND"? This
should be used only if you re-send an entirely unchanged patch,
perhaps because of a correction to the recipients list. Otherwise
please increment the version number.

Jan

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Re: [Xen-devel] [PATCH RESEND] xen: notifier: refine 'notifier_head', use 'list_head' directly

Posted by chenbaodong 4 years, 10 months ago

On 6/3/19 17:28, Jan Beulich wrote:
>>>> On 03.06.19 at 03:33, <chenbaodong@mxnavi.com> wrote:
>> 'notifier_block' can be replaced with 'list_head' when used for
>> 'notifier_head', this make the a little more clear.
>>
>> Signed-off-by: Baodong Chen <chenbaodong@mxnavi.com>
> Oh, and also a remark regarding the title: Why "RESEND"? This
> should be used only if you re-send an entirely unchanged patch,
> perhaps because of a correction to the recipients list. Otherwise
> please increment the version number.

Hello Jan, Thanks for guiding me to the right direction.

This is my first experience sending patch using mail list.

I will use version number instead of resend next time.

> Jan
>
>
> .
>

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