This is a note to let you know that I've just added the patch titled
xen/netback: fix spurious event detection for common event case
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-netback-fix-spurious-event-detection-for-common-.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e46b0ed1d8dcad1659936ab2b4a56c8ff49decf4
Author: Juergen Gross <jgross@xxxxxxxx>
Date: Thu Feb 11 11:16:12 2021 +0100
xen/netback: fix spurious event detection for common event case
[ Upstream commit a3daf3d39132b405781be8d9ede0c449b244b64e ]
In case of a common event for rx and tx queue the event should be
regarded to be spurious if no rx and no tx requests are pending.
Unfortunately the condition for testing that is wrong causing to
decide a event being spurious if no rx OR no tx requests are
pending.
Fix that plus using local variables for rx/tx pending indicators in
order to split function calls and if condition.
Fixes: 23025393dbeb3b ("xen/netback: use lateeoi irq binding")
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Paul Durrant <paul@xxxxxxx>
Reviewed-by: Wei Liu <wl@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index e889488b84a03..8090895873011 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -162,13 +162,15 @@ irqreturn_t xenvif_interrupt(int irq, void *dev_id)
{
struct xenvif_queue *queue = dev_id;
int old;
+ bool has_rx, has_tx;
old = atomic_fetch_or(NETBK_COMMON_EOI, &queue->eoi_pending);
WARN(old, "Interrupt while EOI pending\n");
- /* Use bitwise or as we need to call both functions. */
- if ((!xenvif_handle_tx_interrupt(queue) |
- !xenvif_handle_rx_interrupt(queue))) {
+ has_tx = xenvif_handle_tx_interrupt(queue);
+ has_rx = xenvif_handle_rx_interrupt(queue);
+
+ if (!has_rx && !has_tx) {
atomic_andnot(NETBK_COMMON_EOI, &queue->eoi_pending);
xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
}
