[PATCH 5.9 692/757] mt76: mt7915: do not do any work in napi poll after calling napi_complete_done()

From: Greg Kroah-Hartman
Date: Tue Oct 27 2020 - 12:30:00 EST


From: Felix Fietkau <nbd@xxxxxxxx>

[ Upstream commit 38b04398c532e9bb9aa90fc07846ad0b0845fe94 ]

Fixes a race condition where multiple tx cleanup or sta poll tasks could run
in parallel.

Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/wireless/mediatek/mt76/mt7915/dma.c | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/dma.c b/drivers/net/wireless/mediatek/mt76/mt7915/dma.c
index a8832c5e60041..8a1ae08d9572e 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/dma.c
@@ -95,16 +95,13 @@ static int mt7915_poll_tx(struct napi_struct *napi, int budget)
dev = container_of(napi, struct mt7915_dev, mt76.tx_napi);

mt7915_tx_cleanup(dev);
-
- if (napi_complete_done(napi, 0))
- mt7915_irq_enable(dev, MT_INT_TX_DONE_ALL);
-
- mt7915_tx_cleanup(dev);
-
mt7915_mac_sta_poll(dev);

tasklet_schedule(&dev->mt76.tx_tasklet);

+ if (napi_complete_done(napi, 0))
+ mt7915_irq_enable(dev, MT_INT_TX_DONE_ALL);
+
return 0;
}

--
2.25.1