linux-kernel - Re: [PATCH 06/16] mm/pagemap: Cleanup PREEMPT

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Message-ID: <20201029205717.GA24578@pc636>
Date:   Thu, 29 Oct 2020 21:57:17 +0100
From:   Uladzislau Rezki <urezki@...il.com>
To:     "Paul E . McKenney" <paulmck@...nel.org>
Cc:     LKML <linux-kernel@...r.kernel.org>, RCU <rcu@...r.kernel.org>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Michal Hocko <mhocko@...e.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Theodore Y . Ts'o" <tytso@....edu>,
        Joel Fernandes <joel@...lfernandes.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Oleksiy Avramchenko <oleksiy.avramchenko@...ymobile.com>,
        linux-mm@...ck.org, urezki@...il.com
Subject: Re: [PATCH 06/16] mm/pagemap: Cleanup PREEMPT_COUNT leftovers

On Thu, Oct 29, 2020 at 05:50:09PM +0100, Uladzislau Rezki (Sony) wrote:
> From: Thomas Gleixner <tglx@...utronix.de>
> 
> CONFIG_PREEMPT_COUNT is now unconditionally enabled and will be
> removed. Cleanup the leftovers before doing so.
> 
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> Cc: Andrew Morton <akpm@...ux-foundation.org>
> Cc: linux-mm@...ck.org
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@...il.com>
> ---
>  include/linux/pagemap.h | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index c77b7c31b2e4..cbfbe2bcca75 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -204,9 +204,7 @@ void release_pages(struct page **pages, int nr);
>  static inline int __page_cache_add_speculative(struct page *page, int count)
>  {
>  #ifdef CONFIG_TINY_RCU
> -# ifdef CONFIG_PREEMPT_COUNT
> -	VM_BUG_ON(!in_atomic() && !irqs_disabled());
> -# endif
> +	VM_BUG_ON(preemptible())
>  	/*
>  	 * Preempt must be disabled here - we rely on rcu_read_lock doing
>  	 * this for us.
> -- 
> 2.20.1
> 
Hello, Paul.

Sorry for a small mistake, it was fixed by you before, whereas i took an
old version of the patch that is question. Please use below one instead of
posted one:

Author: Thomas Gleixner <tglx@...utronix.de>
Date:   Mon Sep 14 19:25:00 2020 +0200

    mm/pagemap: Cleanup PREEMPT_COUNT leftovers
    
    CONFIG_PREEMPT_COUNT is now unconditionally enabled and will be
    removed. Cleanup the leftovers before doing so.
    
    Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
    Cc: Andrew Morton <akpm@...ux-foundation.org>
    Cc: linux-mm@...ck.org
    [ paulmck: Fix !SMP build error per kernel test robot feedback. ]
    Signed-off-by: Paul E. McKenney <paulmck@...nel.org>

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 7de11dcd534d..b3d9d9217ea0 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -168,9 +168,7 @@ void release_pages(struct page **pages, int nr);
 static inline int __page_cache_add_speculative(struct page *page, int count)
 {
 #ifdef CONFIG_TINY_RCU
-# ifdef CONFIG_PREEMPT_COUNT
-       VM_BUG_ON(!in_atomic() && !irqs_disabled());
-# endif
+       VM_BUG_ON(preemptible());
        /*
         * Preempt must be disabled here - we rely on rcu_read_lock doing
         * this for us.

--
Vlad Rezki