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Subject: Re: [PATCH v3] LoongArch: Add support to clone a time namespace
To:     Youling Tang <tangyouling@loongson.cn>
References: <1685519761-20425-1-git-send-email-yangtiezhu@loongson.cn>
 <526b7cdc-9d10-d213-4e98-10973483b4cd@loongson.cn>
Cc:     Huacai Chen <chenhuacai@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Christian Brauner <brauner@kernel.org>,
        Andy Lutomirski <luto@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        loongarch@lists.linux.dev, linux-kernel@vger.kernel.org,
        loongson-kernel@lists.loongnix.cn
From:   Tiezhu Yang <yangtiezhu@loongson.cn>
Message-ID: <d116627c-f21f-1f6b-3c3d-96bea9a29393@loongson.cn>
Date:   Wed, 31 May 2023 18:02:05 +0800
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On 05/31/2023 04:34 PM, Youling Tang wrote:
> Hi, Tiezhu
>
> On 05/31/2023 03:56 PM, Tiezhu Yang wrote:

...

> It can also be changed as follows,
>
> enum vvar_pages {
>     VVAR_GENERIC_PAGE_OFFSET,
>     VVAR_TIMENS_PAGE_OFFSET,
>     VVAR_LOONGARCH_PAGES_START,
>     VVAR_LOONGARCH_PAGES_END = VVAR_LOONGARCH_PAGES_START +
> LOONGARCH_VDSO_DATA_PAGES - 1,
>     VVAR_NR_PAGES,
> };
>
> #define VVAR_SIZE (VVAR_NR_PAGES << PAGE_SHIFT)
>
> Which do you think is better?

Thanks, it seems more simple to define VVAR_SIZE and works well
as expected. Let us wait for more review comments before respin.

I will send v4 with the following changes based on the current
patch in the next week.

$ git diff
diff --git a/arch/loongarch/include/asm/vdso/vdso.h 
b/arch/loongarch/include/asm/vdso/vdso.h
index fa6049ef635e..7e9bceb8c009 100644
--- a/arch/loongarch/include/asm/vdso/vdso.h
+++ b/arch/loongarch/include/asm/vdso/vdso.h
@@ -33,15 +33,17 @@ struct loongarch_vdso_data {
   */
  #define LOONGARCH_VDSO_DATA_SIZE PAGE_ALIGN(sizeof(struct 
loongarch_vdso_data))
  #define LOONGARCH_VDSO_DATA_PAGES (LOONGARCH_VDSO_DATA_SIZE >> PAGE_SHIFT)
-#define VVAR_SIZE (VVAR_LOONGARCH_PAGES_START * PAGE_SIZE + 
LOONGARCH_VDSO_DATA_SIZE)

  enum vvar_pages {
         VVAR_GENERIC_PAGE_OFFSET,
         VVAR_TIMENS_PAGE_OFFSET,
         VVAR_LOONGARCH_PAGES_START,
         VVAR_LOONGARCH_PAGES_END = VVAR_LOONGARCH_PAGES_START + 
LOONGARCH_VDSO_DATA_PAGES - 1,
+       VVAR_NR_PAGES,
  };

+#define VVAR_SIZE (VVAR_NR_PAGES << PAGE_SHIFT)
+
  static inline unsigned long get_vdso_base(void)
  {
         unsigned long addr;

Thanks,
Tiezhu