patch "staging: comedi: jr3_pci: cope with jiffies wraparound" added to staging-testing

patch "staging: comedi: jr3_pci: cope with jiffies wraparound" added to staging-testing

[gregkh]

This is a note to let you know that I've just added the patch titled

    staging: comedi: jr3_pci: cope with jiffies wraparound

to my staging git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-testing branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will be merged to the staging-next branch sometime soon,
after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.


>From 9cda79a9a99dfef7dab01fb658b097ed03645182 Mon Sep 17 00:00:00 2001
From: Ian Abbott <abbotti@mev.co.uk>
Date: Fri, 17 Feb 2017 11:09:09 +0000
Subject: staging: comedi: jr3_pci: cope with jiffies wraparound

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>
---
 drivers/staging/comedi/drivers/jr3_pci.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/comedi/drivers/jr3_pci.c b/drivers/staging/comedi/drivers/jr3_pci.c
index 25909a936e7c..eb0a095efe9c 100644
--- a/drivers/staging/comedi/drivers/jr3_pci.c
+++ b/drivers/staging/comedi/drivers/jr3_pci.c
@@ -611,7 +611,7 @@ 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);
-- 
2.11.1