[Xen-devel] xen/pcifront: Use monotonic clock

[Abhilash Jindal <klock.android@xxxxxxxxx>]

Wall time obtained from do_gettimeofday is susceptible to sudden jumps due to user setting the time or due to NTP.

Monotonic time is constantly increasing time better suited for comparing two

timestamps.

---

Âdrivers/pci/xen-pcifront.c | Â 10 +++++-----

Â1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c

index f7197a7..5ef3eb7 100644

--- a/drivers/pci/xen-pcifront.c

+++ b/drivers/pci/xen-pcifront.c

@@ -114,7 +114,7 @@ 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;

+ struct timespec tv;

Â

 spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);

Â

@@ -131,8 +131,8 @@ 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;

+ ktime_get_ts(&tv);

+ ns_timeout = timespec_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;

Â

 xen_clear_irq_pending(irq);

Â

@@ -140,8 +140,8 @@ 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);

+ ktime_get_ts(&tv);

+ ns = timespec_to_ns(&tv);

 if (ns > ns_timeout) {

 dev_err(&pdev->xdev->dev,

 "pciback not responding!!!\n");

--Â

1.7.9.5

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