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Date: Tue, 13 Dec 2016 08:30:13 -0800
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Randy Dunlap <rdunlap@infradead.org>
Cc: Dashi DS1 Cao <caods1@lenovo.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        linux-scsi <linux-scsi@vger.kernel.org>,
        stable <stable@vger.kernel.org>
Subject: Re: version 3.18.44 to 3.18.45 introduced a bug in
 "drivers/scsi/megaraid/megaraid_sas_base.c"
Message-ID: <20161213163013.GB20693@kroah.com>
References: <23B7B563BA4E9446B962B142C86EF24ADB6F24@CNMAILEX03.lenovo.com>
 <a9788b9c-6361-f79e-f851-e8c4871571cb@infradead.org>
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On Tue, Dec 13, 2016 at 08:08:27AM -0800, Randy Dunlap wrote:
> [adding other lists + gregkh]
> 
> 
> On 12/13/16 02:56, Dashi DS1 Cao wrote:
> > --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> > +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> > @@ -1614,16 +1614,13 @@ megasas_queue_command(struct Scsi_Host *shost, struct scsi_cmnd *scmd)
> >                 goto out_done;
> >         }
> > 
> > -       switch (scmd->cmnd[0]) {
> > -       case SYNCHRONIZE_CACHE:
> > -               /*
> > -                * FW takes care of flush cache on its own
> > -                * No need to send it down
> > -                */
> > +       /*
> > +        * FW takes care of flush cache on its own for Virtual Disk.
> > +        * No need to send it down for VD. For JBOD send SYNCHRONIZE_CACHE to FW.
> > +        */
> > +       if ((scmd->cmnd[0] == SYNCHRONIZE_CACHE) && MEGASAS_IS_LOGICAL(scmd)) {
> >                 scmd->result = DID_OK << 16;
> >                 goto out_done;
> > -       default:
> > -               break;
> >         }
> > 
> >         if (instance->instancet->build_and_issue_cmd(instance, scmd)) {
> > 
> > MEGASAS_IS_LOGICAL is defined to be a macro with '?' operator, which has a lower precedence than '&&'.
> > The macro should have been defined as:
> > --- a/drivers/scsi/megaraid/megaraid_sas.h
> > +++ b/drivers/scsi/megaraid/megaraid_sas.h
> > @@ -1823,7 +1823,7 @@ struct megasas_instance_template {
> >  };
> > 
> >  #define MEGASAS_IS_LOGICAL(scp)                                                \
> > -       (scp->device->channel < MEGASAS_MAX_PD_CHANNELS) ? 0 : 1
> > +       ((scp->device->channel < MEGASAS_MAX_PD_CHANNELS) ? 0 : 1)
> > 
> >  #define MEGASAS_DEV_INDEX(inst, scp)                                   \
> >         ((scp->device->channel % 2) * MEGASAS_MAX_DEV_PER_CHANNEL) +    \
> > 
> > Dashi Cao
> > 

I don't maintain 3.18-stable :)

thanks,

greg k-h