From: Arnd Bergmann <arnd@arndb.de>
To: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Subject: Re: [RFC][v6][PATCH 0/9] clone_with_pids() syscall
Date: Sun, 13 Sep 2009 16:36:47 +0200
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Cc: Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org,
       Oren Laadan <orenl@cs.columbia.edu>,
       "Eric W. Biederman" <ebiederm@xmission.com>,
       Alexey Dobriyan <adobriyan@gmail.com>,
       Pavel Emelyanov <xemul@openvz.org>, Andrew Morton <akpm@osdl.org>,
       torvalds@linux-foundation.org, mikew@google.com, mingo@elte.hu,
       hpa@zytor.com, Nathan Lynch <nathanl@austin.ibm.com>,
       container@us.ibm.com, sukadev@us.ibm.com
References: <20090910060627.GA24343@us.ibm.com> <1252688404.7126.40.camel@laptop> <20090912171930.GB29169@us.ibm.com>
In-Reply-To: <20090912171930.GB29169@us.ibm.com>
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On Saturday 12 September 2009, Sukadev Bhattiprolu wrote:
> 
> Peter Zijlstra [peterz@infradead.org] wrote:
> | On Fri, 2009-09-11 at 09:47 -0700, Sukadev Bhattiprolu wrote:
> | > | Also, if you're passing a struct, why not put nr_pids in there, and
> | > | replace clone_pid_struct with a simple array? That would give us
> | > | 
> | > | struct clone_struct {
> | > |         u64 flags;
> | > |         u64 child_stack;
> | > |         u32 child_tid;
> | > |         u32 parent_tid;
> 
> BTW, these two tids are __user pointers that kernel copies data into.
> They should be u64 to avoid conversions in architecture specific code ?
> 

No, they are not pointers, the kernel can directly write into the user
data structure. Indirect pointers would not be helpful here IMHO.

	Arnd <><
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