Re: [Xen-devel] [PATCH v2] xen/pcifront: Remove usage of struct timeval

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Wed, May 20, 2015 at 08:16:24AM -0500, Bjorn Helgaas wrote:
> On Tue, May 19, 2015 at 1:08 AM, Tina Ruchandani
> <ruchandani.tina@xxxxxxxxx> wrote:
> > struct timeval uses a 32-bit field for representing seconds,
> > which will overflow in the year 2038 and beyond. This patch replaces
> > struct timeval with 64-bit ktime_t which is 2038 safe.
> > The patch is part of a larger effort to remove instances of
> > 32-bit timekeeping variables (timeval, time_t and timespec)
> > from the kernel.
> >
> > Signed-off-by: Tina Ruchandani <ruchandani.tina@xxxxxxxxx>
> > Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> 
> Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> 
> This isn't PCI-related, so I expect Konrad, Boris, or David will merge this.

OK. Thanks.
> 
> > --
> > Changes in v2:
> > - Use monotonic time (ktime_get_ns()) instead of real time
> > since we only care about elapsed delta here.
> > - Use macro ktime_get_ns() instead of getting ktime_t and
> > converting it to ns.
> > ---
> >  drivers/pci/xen-pcifront.c | 8 +++-----
> >  1 file changed, 3 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
> > index 7cfd2db..c4796c8 100644
> > --- a/drivers/pci/xen-pcifront.c
> > +++ b/drivers/pci/xen-pcifront.c
> > @@ -20,6 +20,7 @@
> >  #include <linux/workqueue.h>
> >  #include <linux/bitops.h>
> >  #include <linux/time.h>
> > +#include <linux/ktime.h>
> >  #include <xen/platform_pci.h>
> >
> >  #include <asm/xen/swiotlb-xen.h>
> > @@ -115,7 +116,6 @@ static int do_pci_op(struct pcifront_device *pdev, 
> > struct xen_pci_op *op)
> >         evtchn_port_t port = pdev->evtchn;
> >         unsigned irq = pdev->irq;
> >         s64 ns, ns_timeout;
> > -       struct timeval tv;
> >
> >         spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
> >
> > @@ -132,8 +132,7 @@ static int do_pci_op(struct pcifront_device *pdev, 
> > struct xen_pci_op *op)
> >          * (in the latter case we end up continually re-executing poll() 
> > with a
> >          * timeout in the past). 1s difference gives plenty of slack for 
> > error.
> >          */
> > -       do_gettimeofday(&tv);
> > -       ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
> > +       ns_timeout = ktime_get_ns() + 2 * (s64)NSEC_PER_SEC;
> >
> >         xen_clear_irq_pending(irq);
> >
> > @@ -141,8 +140,7 @@ static int do_pci_op(struct pcifront_device *pdev, 
> > struct xen_pci_op *op)
> >                         (unsigned long *)&pdev->sh_info->flags)) {
> >                 xen_poll_irq_timeout(irq, jiffies + 3*HZ);
> >                 xen_clear_irq_pending(irq);
> > -               do_gettimeofday(&tv);
> > -               ns = timeval_to_ns(&tv);
> > +               ns = ktime_get_ns();
> >                 if (ns > ns_timeout) {
> >                         dev_err(&pdev->xdev->dev,
> >                                 "pciback not responding!!!\n");
> > --
> > 2.2.0.rc0.207.ga3a616c
> >

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