@@ -88,6 +88,7 @@ struct xenvif {
unsigned long credit_usec;
unsigned long remaining_credit;
struct timer_list credit_timeout;
+ u64 credit_window_start;
/* Statistics */
unsigned long rx_gso_checksum_fixup;
@@ -273,8 +273,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
vif->credit_bytes = vif->remaining_credit = ~0UL;
vif->credit_usec = 0UL;
init_timer(&vif->credit_timeout);
- /* Initialize 'expires' now: it's used to track the credit window. */
- vif->credit_timeout.expires = jiffies;
+ vif->credit_window_start = get_jiffies_64();
dev->netdev_ops = &xenvif_netdev_ops;
dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
@@ -1427,9 +1427,8 @@ out:
static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
{
- unsigned long now = jiffies;
- unsigned long next_credit =
- vif->credit_timeout.expires +
+ u64 now = get_jiffies_64();
+ u64 next_credit = vif->credit_window_start +
msecs_to_jiffies(vif->credit_usec / 1000);
/* Timer could already be pending in rare cases. */
@@ -1437,8 +1436,8 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
return true;
/* Passed the point where we can replenish credit? */
- if (time_after_eq(now, next_credit)) {
- vif->credit_timeout.expires = now;
+ if (time_after_eq64(now, next_credit)) {
+ vif->credit_window_start = now;
tx_add_credit(vif);
}
@@ -1450,6 +1449,7 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
tx_credit_callback;
mod_timer(&vif->credit_timeout,
next_credit);
+ vif->credit_window_start = next_credit;
return true;
}
This is a note to let you know that I have just added a patch titled xen-netback: use jiffies_64 value to calculate credit timeout to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.14. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 892a8b61569dee530010f9ff56bd09911a3d8350 Mon Sep 17 00:00:00 2001 From: Wei Liu <wei.liu2@citrix.com> Date: Mon, 28 Oct 2013 12:07:57 +0000 Subject: xen-netback: use jiffies_64 value to calculate credit timeout [ Upstream commit 059dfa6a93b779516321e5112db9d7621b1367ba ] time_after_eq() only works if the delta is < MAX_ULONG/2. For a 32bit Dom0, if netfront sends packets at a very low rate, the time between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2 and the test for timer_after_eq() will be incorrect. Credit will not be replenished and the guest may become unable to send packets (e.g., if prior to the long gap, all credit was exhausted). Use jiffies_64 variant to mitigate this problem for 32bit Dom0. Suggested-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Wei Liu <wei.liu2@citrix.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: Ian Campbell <ian.campbell@citrix.com> Cc: Jason Luan <jianhai.luan@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/net/xen-netback/common.h | 1 + drivers/net/xen-netback/interface.c | 3 +-- drivers/net/xen-netback/netback.c | 10 +++++----- 3 files changed, 7 insertions(+), 7 deletions(-) -- 1.8.3.2