From: KY Srinivasan <kys@microsoft.com>
To: Jack Wang <xjtuwjp@gmail.com>
CC: Greg KH <gregkh@linuxfoundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
        "ohering@suse.com" <ohering@suse.com>,
        "jbottomley@parallels.com" <jbottomley@parallels.com>,
        "hch@infradead.org" <hch@infradead.org>,
        "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
        Mike Christie <michaelc@cs.wisc.edu>
Subject: RE: Drivers: scsi: FLUSH timeout
Thread-Topic: Drivers: scsi: FLUSH timeout
Thread-Index: AQHOtkBtWGcmfS/7wkmW+8Ppp9OK8pnPmBJggAU49YCAAAdE0A==
Date: Tue, 24 Sep 2013 12:35:53 +0000
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> -----Original Message-----
> From: Jack Wang [mailto:xjtuwjp@gmail.com]
> Sent: Tuesday, September 24, 2013 5:08 AM
> To: KY Srinivasan
> Cc: Greg KH; linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> ohering@suse.com; jbottomley@parallels.com; hch@infradead.org; linux-
> scsi@vger.kernel.org; Mike Christie
> Subject: Re: Drivers: scsi: FLUSH timeout
> 
> On 09/21/2013 07:24 AM, KY Srinivasan wrote:
> >
> >
> >> -----Original Message-----
> >> From: Greg KH [mailto:gregkh@linuxfoundation.org]
> >> Sent: Friday, September 20, 2013 1:32 PM
> >> To: KY Srinivasan
> >> Cc: linux-kernel@vger.kernel.org; devel@linuxdriverproject.org;
> >> ohering@suse.com; jbottomley@parallels.com; hch@infradead.org; linux-
> >> scsi@vger.kernel.org
> >> Subject: Re: Drivers: scsi: FLUSH timeout
> >>
> >> On Fri, Sep 20, 2013 at 12:32:27PM -0700, K. Y. Srinivasan wrote:
> >>> The SD_FLUSH_TIMEOUT value is currently hardcoded.
> >>
> >> Hardcoded where?  Please, more context.
> >
> > This is defined in scsi/sd.h:
> >
> > #define SD_FLUSH_TIMEOUT        (60 * HZ)
> >>
> >>> On our cloud, we sometimes hit this timeout. I was wondering if we
> >>> could make this a module parameter. If this is acceptable, I can send
> >>> you a patch for this.
> >>
> >> A module parameter don't make sense for a per-device value, does it?
> > Currently, the 60 second timeout is applied across devices. Ideally, I want to be
> > able to control the FLUSH TIMEOUT as we currently do I/O timeout. If this is
> > acceptable, I can work on a patch for that as well.
> >
> > Regards,
> >
> > K. Y
> >>
> >> greg k-h
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> >
> Hi,
> 
> Back to 2010, Mike(cc-ed) try to add a flush time out interface, similar
> to what you want here, no idea why it's just ignored?
> http://www.spinics.net/lists/linux-scsi/msg45017.html

Thanks Jack. Mike, do you know what the concerns were as to why this
patch was not accepted?

Regards,

K. Y 
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