On Mon, Feb 18, 2019 at 01:42:02PM +0100, Walter Harms wrote: > Am 18.02.2019 10:37, schrieb Dan Carpenter: > > 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; > > > > phy_addr = ((dma_addr_t)m_sg->baseaddr_h << 32) | m_sg->baseaddr_l<<16; ^^^^ In the original code, we don't do this shift. regards, dan carpenter