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authorJohan Hovold <jhovold@gmail.com>2014-05-26 19:23:38 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-26 15:10:28 -0400
commit21ffba35838100b5d332a75b418f9de43080d406 (patch)
tree6b457f18c5e16e6b2628e9dd9499ec6863fd15ff
parent97e72c4aa615b5ed6a7c4b22b9fa766679c749bc (diff)
downloadlinux-linaro-stable-21ffba35838100b5d332a75b418f9de43080d406.tar.gz
USB: cdc-acm: fix broken runtime suspend
commit 140cb81ac8c625942a1d695875932c615767a526 upstream. 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@intel.com> Signed-off-by: Johan Hovold <jhovold@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/usb/class/cdc-acm.c32
-rw-r--r--drivers/usb/class/cdc-acm.h2
2 files changed, 23 insertions, 11 deletions
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 06792ee5af08..e7570ecac598 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -234,12 +234,9 @@ static int acm_write_start(struct acm *acm, int wbn)
acm->susp_count);
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 0; /* A white lie */
+ return 0;
}
usb_mark_last_busy(acm->dev);
@@ -610,6 +607,8 @@ 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__);
@@ -618,6 +617,16 @@ 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);
@@ -1211,6 +1220,7 @@ 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) {
@@ -1466,7 +1476,7 @@ 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);
@@ -1478,10 +1488,12 @@ 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 35ef887b7417..96147806b9a4 100644
--- a/drivers/usb/class/cdc-acm.h
+++ b/drivers/usb/class/cdc-acm.h
@@ -117,7 +117,7 @@ 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