linux-kernel - Re: [RESEND PATCH 1/3] uprobes: Remove redundant lock_page/unlock

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Message-ID: <20120601185237.GC31771@redhat.com>
Date:	Fri, 1 Jun 2012 20:52:37 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...e.hu>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Arnaldo Carvalho de Melo <acme@...radead.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Anton Arapov <anton@...hat.com>
Subject: Re: [RESEND PATCH 1/3] uprobes: Remove redundant
	lock_page/unlock_page

On 06/01, Srikar Dronamraju wrote:
>
> @@ -315,12 +315,10 @@ static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_
>  	if (ret <= 0)
>  		return ret;
>
> -	lock_page(page);
>  	vaddr_new = kmap_atomic(page);
>  	vaddr &= ~PAGE_MASK;
>  	memcpy(opcode, vaddr_new + vaddr, UPROBE_SWBP_INSN_SIZE);
>  	kunmap_atomic(vaddr_new);
> -	unlock_page(page);

Great, this lock_page() was really confusing.

Oleg.

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