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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Richard Genoud" <richard.genoud@gmail.com>,
        "Stanislaw Gruszka" <sgruszka@redhat.com>,
        "Kalle Valo" <kvalo@codeaurora.org>
Date:   Sun, 11 Feb 2018 04:20:06 +0000
Message-ID: <lsq.1518322806.426550123@decadent.org.uk>
Subject: [PATCH 3.2 33/79] rt2x00usb: mark device removed when get ENOENT
 usb error
In-Reply-To: <lsq.1518322802.943358572@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.2.99-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Stanislaw Gruszka <sgruszka@redhat.com>

commit bfa62a52cad93686bb8d8171ea5288813248a7c6 upstream.

ENOENT usb error mean "specified interface or endpoint does not exist or
is not enabled". Mark device not present when we encounter this error
similar like we do with ENODEV error.

Otherwise we can have infinite loop in rt2x00usb_work_rxdone(), because
we remove and put again RX entries to the queue infinitely.

We can have similar situation when submit urb will fail all the time
with other error, so we need consider to limit number of entries
processed by rxdone work. But for now, since the patch fixes
reproducible soft lockup issue on single processor systems
and taken ENOENT error meaning, let apply this fix.

Patch adds additional ENOENT check not only in rx kick routine, but
also on other places where we check for ENODEV error.

Reported-by: Richard Genoud <richard.genoud@gmail.com>
Debugged-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Tested-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/net/wireless/rt2x00/rt2x00usb.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/rt2x00/rt2x00usb.c
+++ b/drivers/net/wireless/rt2x00/rt2x00usb.c
@@ -64,7 +64,7 @@ int rt2x00usb_vendor_request(struct rt2x
 		 * -ENODEV: Device has disappeared, no point continuing.
 		 * All other errors: Try again.
 		 */
-		else if (status == -ENODEV) {
+		else if (status == -ENODEV || status == -ENOENT) {
 			clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
 			break;
 		}
@@ -311,7 +311,7 @@ static bool rt2x00usb_kick_tx_entry(stru
 
 	status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC);
 	if (status) {
-		if (status == -ENODEV)
+		if (status == -ENODEV || status == -ENOENT)
 			clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
 		set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
 		rt2x00lib_dmadone(entry);
@@ -400,7 +400,7 @@ static bool rt2x00usb_kick_rx_entry(stru
 
 	status = usb_submit_urb(entry_priv->urb, GFP_ATOMIC);
 	if (status) {
-		if (status == -ENODEV)
+		if (status == -ENODEV || status == -ENOENT)
 			clear_bit(DEVICE_STATE_PRESENT, &rt2x00dev->flags);
 		set_bit(ENTRY_DATA_IO_FAILED, &entry->flags);
 		rt2x00lib_dmadone(entry);