This is a note to let you know that I've just added the patch titled
USB: cdc-acm: fix broken runtime suspend
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will also be merged in the next major kernel release
during the merge window.
If you have any questions about this process, please let me know.
>From 140cb81ac8c625942a1d695875932c615767a526 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@xxxxxxxxx>
Date: Mon, 26 May 2014 19:23:38 +0200
Subject: USB: cdc-acm: fix broken runtime suspend
The current ACM runtime-suspend implementation is broken in several
ways:
Firstly, it buffers only the first write request being made while
suspended -- any further writes are silently dropped.
Secondly, writes being dropped also leak write urbs, which are never
reclaimed (until the device is unbound).
Thirdly, even the single buffered write is not cleared at shutdown
(which may happen before the device is resumed), something which can
lead to another urb leak as well as a PM usage-counter leak.
Fix this by implementing a delayed-write queue using urb anchors and
making sure to discard the queue properly at shutdown.
Fixes: 11ea859d64b6 ("USB: additional power savings for cdc-acm devices
that support remote wakeup")
Reported-by: Xiao Jin <jin.xiao@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # v2.6.27
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/class/cdc-acm.c | 32 ++++++++++++++++++++++----------
drivers/usb/class/cdc-acm.h | 2 +-
2 files changed, 23 insertions(+), 11 deletions(-)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index e72a657a6177..56419254ef75 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -573,6 +573,8 @@ static void acm_port_destruct(struct tty_port *port)
static void acm_port_shutdown(struct tty_port *port)
{
struct acm *acm = container_of(port, struct acm, port);
+ struct urb *urb;
+ struct acm_wb *wb;
int i;
dev_dbg(&acm->control->dev, "%s\n", __func__);
@@ -581,6 +583,16 @@ static void acm_port_shutdown(struct tty_port *port)
if (!acm->disconnected) {
usb_autopm_get_interface(acm->control);
acm_set_control(acm, acm->ctrlout = 0);
+
+ for (;;) {
+ urb = usb_get_from_anchor(&acm->delayed);
+ if (!urb)
+ break;
+ wb = urb->context;
+ wb->use = 0;
+ usb_autopm_put_interface_async(acm->control);
+ }
+
usb_kill_urb(acm->ctrlurb);
for (i = 0; i < ACM_NW; i++)
usb_kill_urb(acm->wb[i].urb);
@@ -648,12 +660,9 @@ static int acm_tty_write(struct tty_struct *tty,
usb_autopm_get_interface_async(acm->control);
if (acm->susp_count) {
- if (!acm->delayed_wb)
- acm->delayed_wb = wb;
- else
- usb_autopm_put_interface_async(acm->control);
+ usb_anchor_urb(wb->urb, &acm->delayed);
spin_unlock_irqrestore(&acm->write_lock, flags);
- return count; /* A white lie */
+ return count;
}
usb_mark_last_busy(acm->dev);
@@ -1269,6 +1278,7 @@ made_compressed_probe:
acm->bInterval = epread->bInterval;
tty_port_init(&acm->port);
acm->port.ops = &acm_port_ops;
+ init_usb_anchor(&acm->delayed);
buf = usb_alloc_coherent(usb_dev, ctrlsize, GFP_KERNEL, &acm->ctrl_dma);
if (!buf) {
@@ -1539,7 +1549,7 @@ static int acm_suspend(struct usb_interface *intf, pm_message_t message)
static int acm_resume(struct usb_interface *intf)
{
struct acm *acm = usb_get_intfdata(intf);
- struct acm_wb *wb;
+ struct urb *urb;
int rv = 0;
spin_lock_irq(&acm->read_lock);
@@ -1551,10 +1561,12 @@ static int acm_resume(struct usb_interface *intf)
if (test_bit(ASYNCB_INITIALIZED, &acm->port.flags)) {
rv = usb_submit_urb(acm->ctrlurb, GFP_ATOMIC);
- if (acm->delayed_wb) {
- wb = acm->delayed_wb;
- acm->delayed_wb = NULL;
- acm_start_wb(acm, wb);
+ for (;;) {
+ urb = usb_get_from_anchor(&acm->delayed);
+ if (!urb)
+ break;
+
+ acm_start_wb(acm, urb->context);
}
/*
diff --git a/drivers/usb/class/cdc-acm.h b/drivers/usb/class/cdc-acm.h
index e38dc785808f..80826f843e04 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -120,7 +120,7 @@ struct acm {
unsigned int throttled:1; /* actually throttled */
unsigned int throttle_req:1; /* throttle requested */
u8 bInterval;
- struct acm_wb *delayed_wb; /* write queued for a device about to be woken */
+ struct usb_anchor delayed; /* writes queued for a device about to be woken */
};
#define CDC_DATA_INTERFACE_TYPE 0x0a
--
1.9.0
--
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