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From:   Lorenzo Bianconi <lorenzo@kernel.org>
To:     kubakici@wp.pl
Cc:     linux-wireless@vger.kernel.org, lorenzo.bianconi@redhat.com
Subject: [PATCH] mt7601u: do not schedule rx_tasklet when the device has been disconnected
Date:   Thu,  6 Jun 2019 14:26:12 +0200
Message-Id: <a3c72b07e229e1d16e93438d741d69abba6a18cf.1559822991.git.lorenzo@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

Do not schedule rx_tasklet when the usb dongle is disconnected. This
patch fixes the common kernel warning reported when the device is
removed.

[   24.921354] usb 3-14: USB disconnect, device number 7
[   24.921593] ------------[ cut here ]------------
[   24.921594] RX urb mismatch
[   24.921675] WARNING: CPU: 4 PID: 163 at drivers/net/wireless/mediatek/mt7601u/dma.c:200 mt7601u_complete_rx+0xcb/0xd0 [mt7601u]
[   24.921769] CPU: 4 PID: 163 Comm: kworker/4:2 Tainted: G           OE     4.19.31-041931-generic #201903231635
[   24.921770] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./Z97 Extreme4, BIOS P1.30 05/23/2014
[   24.921782] Workqueue: usb_hub_wq hub_event
[   24.921797] RIP: 0010:mt7601u_complete_rx+0xcb/0xd0 [mt7601u]
[   24.921800] RSP: 0018:ffff9bd9cfd03d08 EFLAGS: 00010086
[   24.921802] RAX: 0000000000000000 RBX: ffff9bd9bf043540 RCX: 0000000000000006
[   24.921803] RDX: 0000000000000007 RSI: 0000000000000096 RDI: ffff9bd9cfd16420
[   24.921804] RBP: ffff9bd9cfd03d28 R08: 0000000000000002 R09: 00000000000003a8
[   24.921805] R10: 0000002f485fca34 R11: 0000000000000000 R12: ffff9bd9bf043c1c
[   24.921806] R13: ffff9bd9c62fa3c0 R14: 0000000000000082 R15: 0000000000000000
[   24.921807] FS:  0000000000000000(0000) GS:ffff9bd9cfd00000(0000) knlGS:0000000000000000
[   24.921808] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   24.921808] CR2: 00007fb2648b0000 CR3: 0000000142c0a004 CR4: 00000000001606e0
[   24.921809] Call Trace:
[   24.921812]  <IRQ>
[   24.921819]  __usb_hcd_giveback_urb+0x8b/0x140
[   24.921821]  usb_hcd_giveback_urb+0xca/0xe0
[   24.921828]  xhci_giveback_urb_in_irq.isra.42+0x82/0xf0
[   24.921834]  handle_cmd_completion+0xe02/0x10d0
[   24.921837]  xhci_irq+0x274/0x4a0
[   24.921838]  xhci_msi_irq+0x11/0x20
[   24.921851]  __handle_irq_event_percpu+0x44/0x190
[   24.921856]  handle_irq_event_percpu+0x32/0x80
[   24.921861]  handle_irq_event+0x3b/0x5a
[   24.921867]  handle_edge_irq+0x80/0x190
[   24.921874]  handle_irq+0x20/0x30
[   24.921889]  do_IRQ+0x4e/0xe0
[   24.921891]  common_interrupt+0xf/0xf
[   24.921892]  </IRQ>
[   24.921900] RIP: 0010:usb_hcd_flush_endpoint+0x78/0x180
[   24.921354] usb 3-14: USB disconnect, device number 7

Fixes: c869f77d6abb ("add mt7601u driver")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
I will post a patch to fix tx side as well
---
 drivers/net/wireless/mediatek/mt7601u/dma.c | 33 ++++++++++-----------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt7601u/dma.c b/drivers/net/wireless/mediatek/mt7601u/dma.c
index f7edeffb2b19..e7703990b291 100644
--- a/drivers/net/wireless/mediatek/mt7601u/dma.c
+++ b/drivers/net/wireless/mediatek/mt7601u/dma.c
@@ -193,10 +193,20 @@ static void mt7601u_complete_rx(struct urb *urb)
 	struct mt7601u_rx_queue *q = &dev->rx_q;
 	unsigned long flags;
 
-	spin_lock_irqsave(&dev->rx_lock, flags);
+	switch (urb->status) {
+	case -ECONNRESET:
+	case -ESHUTDOWN:
+	case -ENOENT:
+		return;
+	default:
+		dev_err_ratelimited(dev->dev, "rx urb failed: %d\n",
+				    urb->status);
+		/* fall through */
+	case 0:
+		break;
+	}
 
-	if (mt7601u_urb_has_error(urb))
-		dev_err(dev->dev, "Error: RX urb failed:%d\n", urb->status);
+	spin_lock_irqsave(&dev->rx_lock, flags);
 	if (WARN_ONCE(q->e[q->end].urb != urb, "RX urb mismatch"))
 		goto out;
 
@@ -363,19 +373,10 @@ int mt7601u_dma_enqueue_tx(struct mt7601u_dev *dev, struct sk_buff *skb,
 static void mt7601u_kill_rx(struct mt7601u_dev *dev)
 {
 	int i;
-	unsigned long flags;
-
-	spin_lock_irqsave(&dev->rx_lock, flags);
 
-	for (i = 0; i < dev->rx_q.entries; i++) {
-		int next = dev->rx_q.end;
-
-		spin_unlock_irqrestore(&dev->rx_lock, flags);
-		usb_poison_urb(dev->rx_q.e[next].urb);
-		spin_lock_irqsave(&dev->rx_lock, flags);
-	}
-
-	spin_unlock_irqrestore(&dev->rx_lock, flags);
+	for (i = 0; i < dev->rx_q.entries; i++)
+		usb_poison_urb(dev->rx_q.e[i].urb);
+	tasklet_kill(&dev->rx_tasklet);
 }
 
 static int mt7601u_submit_rx_buf(struct mt7601u_dev *dev,
@@ -525,8 +526,6 @@ void mt7601u_dma_cleanup(struct mt7601u_dev *dev)
 {
 	mt7601u_kill_rx(dev);
 
-	tasklet_kill(&dev->rx_tasklet);
-
 	mt7601u_free_rx(dev);
 	mt7601u_free_tx(dev);
 
-- 
2.21.0