linux-kernel - [PATCH net-next v2 5/7] net: ipa: disable interrupt and NAPI after channel stop

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Date:   Mon,  1 Feb 2021 11:28:48 -0600
From:   Alex Elder <elder@...aro.org>
To:     davem@...emloft.net, kuba@...nel.org
Cc:     willemdebruijn.kernel@...il.com, elder@...nel.org,
        evgreen@...omium.org, bjorn.andersson@...aro.org,
        cpratapa@...eaurora.org, subashab@...eaurora.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH net-next v2 5/7] net: ipa: disable interrupt and NAPI after channel stop

Disable both the I/O completion interrupt and NAPI polling on a
channel *after* we successfully stop it rather than before.  This
ensures a completion occurring just before the channel is stopped
gets processed.

Enable NAPI polling and the interrupt *before* starting a channel
rather than after, to be symmetric.  A stopped channel won't
generate any completion interrupts anyway.

Enable NAPI before the interrupt and disable it afterward.

Signed-off-by: Alex Elder <elder@...aro.org>
---
v2: Update code for *both* NAPI and the completion interrupt.

 drivers/net/ipa/gsi.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ipa/gsi.c b/drivers/net/ipa/gsi.c
index 565c785e33a25..93e1d29b28385 100644
--- a/drivers/net/ipa/gsi.c
+++ b/drivers/net/ipa/gsi.c
@@ -860,15 +860,18 @@ static int __gsi_channel_start(struct gsi_channel *channel, bool start)
 	struct gsi *gsi = channel->gsi;
 	int ret;
 
+	napi_enable(&channel->napi);
+	gsi_irq_ieob_enable_one(gsi, channel->evt_ring_id);
+
 	mutex_lock(&gsi->mutex);
 
 	ret = start ? gsi_channel_start_command(channel) : 0;
 
 	mutex_unlock(&gsi->mutex);
 
-	if (!ret) {
-		gsi_irq_ieob_enable_one(gsi, channel->evt_ring_id);
-		napi_enable(&channel->napi);
+	if (ret) {
+		gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
+		napi_disable(&channel->napi);
 	}
 
 	return ret;
@@ -908,14 +911,11 @@ static int __gsi_channel_stop(struct gsi_channel *channel, bool stop)
 	int ret;
 
 	gsi_channel_trans_quiesce(channel);
-	napi_disable(&channel->napi);
-	gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
 
 	ret = stop ? gsi_channel_stop_retry(channel) : 0;
-
-	if (ret) {
-		gsi_irq_ieob_enable_one(gsi, channel->evt_ring_id);
-		napi_enable(&channel->napi);
+	if (!ret) {
+		gsi_irq_ieob_disable_one(gsi, channel->evt_ring_id);
+		napi_disable(&channel->napi);
 	}
 
 	return ret;
-- 
2.27.0