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@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Reviewed-by: Wei Liu <wl@xen.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index c960cb7e3251f67c240f130d7793bdb9586da0f4..3b5fdb24ef1b9d968f5360992cc817ab2bb9727f 100644 (file)
--- 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);
        }