| From 5438432701ce3b080eec7254338d131b24518e82 Mon Sep 17 00:00:00 2001 |
| From: Ian Abbott <abbotti@mev.co.uk> |
| Date: Fri, 17 Feb 2017 11:09:09 +0000 |
| Subject: [PATCH] staging: comedi: jr3_pci: cope with jiffies wraparound |
| |
| commit 8ec04a491825e08068e92bed0bba7821893b6433 upstream. |
| |
| The timer expiry routine `jr3_pci_poll_dev()` checks for expiry by |
| checking whether the absolute value of `jiffies` (stored in local |
| variable `now`) is greater than the expected expiry time in jiffy units. |
| This will fail when `jiffies` wraps around. Also, it seems to make |
| sense to handle the expiry one jiffy earlier than the current test. Use |
| `time_after_eq()` to check for expiry. |
| |
| Cc: <stable@vger.kernel.org> # 3.15+ |
| Signed-off-by: Ian Abbott <abbotti@mev.co.uk> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/staging/comedi/drivers/jr3_pci.c b/drivers/staging/comedi/drivers/jr3_pci.c |
| index d7e2fd438576..d08cdd318a67 100644 |
| --- a/drivers/staging/comedi/drivers/jr3_pci.c |
| +++ b/drivers/staging/comedi/drivers/jr3_pci.c |
| @@ -610,7 +610,7 @@ static void jr3_pci_poll_dev(unsigned long data) |
| s = &dev->subdevices[i]; |
| spriv = s->private; |
| |
| - if (now > spriv->next_time_min) { |
| + if (time_after_eq(now, spriv->next_time_min)) { |
| struct jr3_pci_poll_delay sub_delay; |
| |
| sub_delay = jr3_pci_poll_subdevice(s); |
| -- |
| 2.12.0 |
| |
