On Fri, Mar 08, 2013 at 10:50:19PM +0000, James Bottomley wrote:
> On Fri, 2013-03-08 at 12:57 -0500, Douglas Gilbert wrote:
> > On 13-03-08 07:02 AM, Dan Carpenter wrote:
> > > Static checkers complain that this allocation isn't checked. We
> > > should return zero if the allocation fails.
> > >
> > > Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> > >
> > > diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
> > > index 1b68142..a022997 100644
> > > --- a/drivers/scsi/scsi_transport_sas.c
> > > +++ b/drivers/scsi/scsi_transport_sas.c
> > > @@ -379,9 +379,12 @@ sas_tlr_supported(struct scsi_device *sdev)
> > > {
> > > const int vpd_len = 32;
> > > struct sas_end_device *rdev = sas_sdev_to_rdev(sdev);
> > > - char *buffer = kzalloc(vpd_len, GFP_KERNEL);
> > > + char *buffer;
> > > int ret = 0;
> > >
> > > + buffer = kzalloc(vpd_len, GFP_KERNEL);
> > > + if (!buffer)
> > > + goto out;
> > > if (scsi_get_vpd_page(sdev, 0x90, buffer, vpd_len))
> > > goto out;
> > >
> >
> > For 32 bytes, why not use the stack?
>
> Because the buffer is a DMA target. You can't DMA to stack because of
> padding and cacheline issues.
>
I think stack data works here. scsi_execute() calls
blk_rq_map_kern() which handles stack memory and alignment issues.
regards,
dan carpenter
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