Re: [PATCH 4.4 52/97] mtip32xx: use runtime tag to initialize command header

[Greg Kroah-Hartman]

On Tue, Apr 03, 2018 at 10:01:05PM +0100, Ben Hutchings wrote:
> On Fri, 2018-03-23 at 10:54 +0100, Greg Kroah-Hartman wrote:
> > 4.4-stable review patch.  If anyone has any objections, please let me know.
> > 
> > ------------------
> > 
> > From: Ming Lei <ming.lei@xxxxxxxxxx>
> > 
> > 
> > [ Upstream commit a4e84aae8139aca9fbfbced1f45c51ca81b57488 ]
> > 
> > mtip32xx supposes that 'request_idx' passed to .init_request()
> > is tag of the request, and use that as request's tag to initialize
> > command header.
> > 
> > After MQ IO scheduler is in, request tag assigned isn't same with
> > the request index anymore, so cause strange hardware failure on
> > mtip32xx, even whole system panic is triggered.
> [...]
> 
> MQ IO schedulers were introduced in 4.11, so this shouldn't be needed
> in older branches.  It also causes a performance regression (fixed
> upstream).  Please revert this for 4.4 and 4.9.

Now reverted, thanks.

greg k-h