[3.16.y-ckt stable] Patch "usb: cdc-acm: handle unlinked urb in acm read callback" has been added to the 3.16.y-ckt tree
Luis Henriques
luis.henriques at canonical.com
Wed Feb 17 10:49:00 UTC 2016
This is a note to let you know that I have just added a patch titled
usb: cdc-acm: handle unlinked urb in acm read callback
to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue
This patch is scheduled to be released in version 3.16.7-ckt25.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Luis
---8<------------------------------------------------------------
>From 291625aa7c42c080fcf67f64f47c42d3598bf80d Mon Sep 17 00:00:00 2001
From: Lu Baolu <baolu.lu at linux.intel.com>
Date: Wed, 30 Dec 2015 12:59:08 +0800
Subject: usb: cdc-acm: handle unlinked urb in acm read callback
commit 19454462acb1bdef80542061bdc9b410e4ed1ff6 upstream.
In current acm driver, the bulk-in callback function ignores the
URBs unlinked in usb core.
This causes unexpected data loss in some cases. For example,
runtime suspend entry will unlinked all urbs and set urb->status
to -ENOENT even those urbs might have data not processed yet.
Hence, data loss occurs.
This patch lets bulk-in callback function handle unlinked urbs
to avoid data loss.
Signed-off-by: Tang Jian Qiang <jianqiang.tang at intel.com>
Signed-off-by: Lu Baolu <baolu.lu at linux.intel.com>
Acked-by: Oliver Neukum <oneukum at suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
[ luis: backported to 3.16:
- use 'urb->status' instead of local variable 'status'
- adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
drivers/usb/class/cdc-acm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index f2dc4628fb05..9cda90098a57 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -427,7 +427,8 @@ static void acm_read_bulk_callback(struct urb *urb)
if (urb->status) {
dev_dbg(&acm->data->dev, "%s - non-zero urb status: %d\n",
__func__, urb->status);
- return;
+ if ((urb->status != -ENOENT) || (urb->actual_length == 0))
+ return;
}
usb_mark_last_busy(acm->dev);
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