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Date: Thu, 19 May 2011 13:08:38 +0900
Message-ID: <BANLkTin4w1QyL1NyTyrZARPWASai45W_4Q@mail.gmail.com>
Subject: Re: [PATCH 1/3] mpt2sas: remove the use of writeq, since writeq is
	not atomic
From: Hitoshi Mitake <h.mitake@gmail.com>
To: "Moore, Eric" <Eric.Moore@lsi.com>
Content-Type: text/plain; charset=ISO-8859-1
Cc: linux-arch <linux-arch@vger.kernel.org>, "Prakash,
	Sathya" <Sathya.Prakash@lsi.com>, "Desai, Kashyap" <Kashyap.Desai@lsi.com>,
	linux scsi dev <linux-scsi@vger.kernel.org>,
	Matthew Wilcox <matthew@wil.cx>,
	linux powerpc dev <linuxppc-dev@lists.ozlabs.org>,
	Milton Miller <miltonm@bga.com>,
	linux kernel <linux-kernel@vger.kernel.org>,
	James Bottomley <James.Bottomley@hansenpartnership.com>,
	Ingo Molnar <mingo@redhat.com>, "paulus@samba.org" <paulus@samba.org>,
	linux pci <linux-pci@vger.kernel.org>,
	Ingo Molnar <mingo@elte.hu>, Sam Ravnborg <sam@ravnborg.org>
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On Thu, May 19, 2011 at 04:11, Moore, Eric <Eric.Moore@lsi.com> wrote:
> On Wednesday, May 18, 2011 12:31 PM Milton Miller wrote:
>> Ingo I would propose the following commits added in 2.6.29 be reverted.
>> I think the current concensus is drivers must know if the writeq is
>> not atomic so they can provide their own locking or other workaround.
>>
>
>
> Exactly.
>

The original motivation of preparing common readq/writeq is that
letting each driver
have their own readq/writeq is bad for maintenance of source code.

But if you really dislike them, there might be two solutions:

1. changing the name of readq/writeq to readq_nonatomic/writeq_nonatomic
2. adding new C file to somewhere and defining spinlock for them.
    With spin_lock_irqsave() and spin_unlock_irqrestore() on the spinlock,
    readq/writeq can be atomic.

How do you think about them? If you cannot agree with the above two solutions,
I'll agree with reverting them.

-- 
Hitoshi Mitake
h.mitake@gmail.com