linux-kernel - Re: [PATCH 21/21] memblock: drop memblock_alloc_*

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Message-ID: <20190117092842.wnvsc6em5mxga3rn@pathway.suse.cz>
Date:   Thu, 17 Jan 2019 10:28:42 +0100
From:   Petr Mladek <pmladek@...e.com>
To:     Mike Rapoport <rppt@...ux.ibm.com>
Cc:     linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Christoph Hellwig <hch@....de>,
        "David S. Miller" <davem@...emloft.net>,
        Dennis Zhou <dennis@...nel.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Greentime Hu <green.hu@...il.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Guan Xuetao <gxt@....edu.cn>, Guo Ren <guoren@...nel.org>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Mark Salter <msalter@...hat.com>,
        Matt Turner <mattst88@...il.com>,
        Max Filippov <jcmvbkbc@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Michal Simek <monstr@...str.eu>,
        Paul Burton <paul.burton@...s.com>,
        Rich Felker <dalias@...c.org>,
        Richard Weinberger <richard@....at>,
        Rob Herring <robh+dt@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Stafford Horne <shorne@...il.com>,
        Tony Luck <tony.luck@...el.com>,
        Vineet Gupta <vgupta@...opsys.com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        devicetree@...r.kernel.org, kasan-dev@...glegroups.com,
        linux-alpha@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
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Subject: Re: [PATCH 21/21] memblock: drop memblock_alloc_*_nopanic() variants

On Wed 2019-01-16 15:44:21, Mike Rapoport wrote:
> As all the memblock allocation functions return NULL in case of error
> rather than panic(), the duplicates with _nopanic suffix can be removed.

[...]

> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index c4f0a41..ae65221 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -1147,17 +1147,14 @@ void __init setup_log_buf(int early)
>  	if (!new_log_buf_len)
>  		return;
>  
> -	if (early) {
> -		new_log_buf =
> -			memblock_alloc(new_log_buf_len, LOG_ALIGN);
> -	} else {
> -		new_log_buf = memblock_alloc_nopanic(new_log_buf_len,
> -							  LOG_ALIGN);
> -	}
> -
> +	new_log_buf = memblock_alloc(new_log_buf_len, LOG_ALIGN);

The above change is enough.

>  	if (unlikely(!new_log_buf)) {
> -		pr_err("log_buf_len: %lu bytes not available\n",
> -			new_log_buf_len);
> +		if (early)
> +			panic("log_buf_len: %lu bytes not available\n",
> +				new_log_buf_len);

panic() is not needed here. printk() will just continue using
the (smaller) static buffer.

> +		else
> +			pr_err("log_buf_len: %lu bytes not available\n",
> +			       new_log_buf_len);
>  		return;
>  	}

Best Regards,
Petr