On Sat, Feb 16, 2019 at 05:27:16PM +0100, Walter Harms wrote:
> Am 16.02.2019 15:44, schrieb Colin King:
> > From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> >
> > Currently m_sg->baseaddr_h (a 32 bit unsigned int) is being shifted by a
> > total of 32 bits; this always produces a 0 result. Fix this by casting
> > it to a dma_addr_t (a 64 bit unsigned int) before performing the shift.
> >
> > Detected by CoverityScan, CID#147270 ("Operands don't affect result")
> >
> > Fixes: f0c568a478f0 ("[SCSI] mvumi: Add Marvell UMI driver")
> > Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > ---
> > drivers/scsi/mvumi.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/scsi/mvumi.c b/drivers/scsi/mvumi.c
> > index 36f64205ecfa..d3582accfd09 100644
> > --- a/drivers/scsi/mvumi.c
> > +++ b/drivers/scsi/mvumi.c
> > @@ -313,7 +313,7 @@ static void mvumi_delete_internal_cmd(struct mvumi_hba
> > *mhba,
> > sgd_getsz(mhba, m_sg, size);
> >
> > phy_addr = (dma_addr_t) m_sg->baseaddr_l |
> > - (dma_addr_t) ((m_sg->baseaddr_h << 16) << 16);
> > + (((dma_addr_t) m_sg->baseaddr_h << 16) << 16);
> >
> > dma_free_coherent(&mhba->pdev->dev, size, cmd->data_buf,
> > phy_addr);
>
> i would suggest to try a version with less casts to make it more readable
> like this untested suggestion:
>
> phy_addr =(m_sg->baseaddr_h << 16)| m_sg->baseaddr_l;
> phy_addr <<= 16;
>
That would be a behavior change but it also might be a bugfix? Why
doesn't the code just do:
phy_addr = ((dma_addr_t)m_sg->baseaddr_h << 32) | m_sg->baseaddr_l;
(Probably they broke it up into two shifts to silence a GCC warning that
the shift was wrong because of the missing cast?)
regards,
dan carpenter
