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From: Juergen Gross <jgross@suse.com>
To: xen-devel@lists.xenproject.org, netdev@vger.kernel.org,
Cc: Juergen Gross <jgross@suse.com>, Wei Liu <wei.liu@kernel.org>,
	Paul Durrant <paul@xen.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	stable@vger.kernel.org, Jan Beulich <jbeulich@suse.com>,
	Wei Liu <wl@xen.org>
Subject: [PATCH v3 4/8] xen/netback: fix spurious event detection for common event case
Date: Fri, 19 Feb 2021 16:40:26 +0100	[thread overview]
Message-ID: <20210219154030.10892-5-jgross@suse.com> (raw)
In-Reply-To: <20210219154030.10892-1-jgross@suse.com>

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

Fix that plus using local variables for rx/tx pending indicators in
order to split function calls and if condition.

Cc: stable@vger.kernel.org
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>
- new patch, fixing FreeBSD performance issue
 drivers/net/xen-netback/interface.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index acb786d8b1d8..e02a4fbb74de 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);

  parent reply	other threads:[~2021-02-19 15:41 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-19 15:40 [PATCH v3 0/8] xen/events: bug fixes and some diagnostic aids Juergen Gross
2021-02-19 15:40 ` [PATCH v3 1/8] xen/events: reset affinity of 2-level event when tearing it down Juergen Gross
2021-02-19 15:40 ` [PATCH v3 2/8] xen/events: don't unmask an event channel when an eoi is pending Juergen Gross
2021-02-20 12:10   ` Julien Grall
2021-02-23  9:26   ` Ross Lagerwall
2021-03-05 10:53     ` Jürgen Groß
2021-03-06 16:18     ` Jürgen Groß
2021-02-19 15:40 ` [PATCH v3 3/8] xen/events: avoid handling the same event on two cpus at the same time Juergen Gross
2021-02-20 12:12   ` Julien Grall
2021-02-19 15:40 ` Juergen Gross [this message]
2021-02-19 15:40 ` [PATCH v3 5/8] xen/events: link interdomain events to associated xenbus device Juergen Gross
2021-02-22 14:50   ` Roger Pau Monné
2021-02-19 15:40 ` [PATCH v3 6/8] xen/events: add per-xenbus device event statistics and settings Juergen Gross
2021-02-19 15:40 ` [PATCH v3 7/8] xen/evtchn: use smp barriers for user event ring Juergen Gross
2021-02-19 15:40 ` [PATCH v3 8/8] xen/evtchn: use READ/WRITE_ONCE() for accessing ring indices Juergen Gross
2021-02-20 20:35   ` Boris Ostrovsky
2021-02-23 15:44 ` [PATCH v3 0/8] xen/events: bug fixes and some diagnostic aids Boris Ostrovsky

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