[PATCH] usb:musb: Dequeue urbs on device unplug

From: Virupax Sadashivpetimath
Date: Wed Oct 10 2012 - 00:37:58 EST

Flush queued urbs on receiving device disconnect
interrupt. This is required for successful disconnect
and successive enumeration of the device.

In a failure case khubd hangs on usb-storage thread
for completion. Seen in the below trace.

[ 1355.764526] SysRq : Show Blocked State
[ 1355.768341] task PC stack pid father
[ 1355.773620] khubd D c06a1fbc 0 503 2 0x00000000
[ 1355.780151] [<c06a1fbc>] (__schedule+0x3f0/0x8ec) from [<c06a26a0>] (schedule+0x58/0x70)
[ 1355.788330] [<c06a26a0>] (schedule+0x58/0x70) from [<c06a2af8>] (schedule_timeout+0x1d8/0x31c)
[ 1355.796997] [<c06a2af8>] (schedule_timeout+0x1d8/0x31c) from [<c06a1994>] (wait_for_common+0xd8/0x180)
[ 1355.806396] [<c06a1994>] (wait_for_common+0xd8/0x180) from [<c06a1b14>] (wait_for_completion+0x20/0x24)
[ 1355.815887] [<c06a1b14>] (wait_for_completion+0x20/0x24) from [<c00b9998>] (kthread_stop+0x68/0x17c)
[ 1355.825103] [<c00b9998>] (kthread_stop+0x68/0x17c) from [<c039e0e0>] (release_everything+0x30/0x8c)
[ 1355.834228] [<c039e0e0>] (release_everything+0x30/0x8c) from [<c039e168>] (usb_stor_disconnect+0x2c/0x30)
[ 1355.843902] [<c039e168>] (usb_stor_disconnect+0x2c/0x30) from [<c038e3a8>] (usb_unbind_interface+0x60/0x1e0)
[ 1355.853820] [<c038e3a8>] (usb_unbind_interface+0x60/0x1e0) from [<c031dcc0>] (__device_release_driver+0x80/0xd0)
[ 1355.864074] [<c031dcc0>] (__device_release_driver+0x80/0xd0) from [<c031ddfc>] (device_release_driver+0x2c/0x38)
[ 1355.874359] [<c031ddfc>] (device_release_driver+0x2c/0x38) from [<c031d0d8>] (bus_remove_device+0xbc/0x10c)
[ 1355.884155] [<c031d0d8>] (bus_remove_device+0xbc/0x10c) from [<c031b63c>] (device_del+0x108/0x17c)
[ 1355.893188] [<c031b63c>] (device_del+0x108/0x17c) from [<c038afe8>] (usb_disable_device+0xbc/0x200)
[ 1355.902313] [<c038afe8>] (usb_disable_device+0xbc/0x200) from [<c0384c58>] (usb_disconnect+0xb8/0x194)
[ 1355.911682] [<c0384c58>] (usb_disconnect+0xb8/0x194) from [<c0385e58>] (hub_thread+0x45c/0x14b0)
[ 1355.920562] [<c0385e58>] (hub_thread+0x45c/0x14b0) from [<c00b97e0>] (kthread+0x98/0xa0)
[ 1355.928710] [<c00b97e0>] (kthread+0x98/0xa0) from [<c0064834>] (kernel_thread_exit+0x0/0x8)
[ 1356.014373] usb-storage D c06a1fbc 0 2379 2 0x00000000
[ 1356.020843] [<c06a1fbc>] (__schedule+0x3f0/0x8ec) from [<c06a26a0>] (schedule+0x58/0x70)
[ 1356.029022] [<c06a26a0>] (schedule+0x58/0x70) from [<c06a2af8>] (schedule_timeout+0x1d8/0x31c)
[ 1356.037719] [<c06a2af8>] (schedule_timeout+0x1d8/0x31c) from [<c06a1994>] (wait_for_common+0xd8/0x180)
[ 1356.047088] [<c06a1994>] (wait_for_common+0xd8/0x180) from [<c06a1b14>] (wait_for_completion+0x20/0x24)
[ 1356.056549] [<c06a1b14>] (wait_for_completion+0x20/0x24) from [<c038b5dc>] (usb_sg_wait+0x108/0x194)
[ 1356.065795] [<c038b5dc>] (usb_sg_wait+0x108/0x194) from [<c039d6dc>] (usb_stor_bulk_transfer_sglist+0x9c/0xf4)
[ 1356.075866] [<c039d6dc>] (usb_stor_bulk_transfer_sglist+0x9c/0xf4) from [<c039d76c>] (usb_stor_bulk_srb+0x38/0x50)
[ 1356.086303] [<c039d76c>] (usb_stor_bulk_srb+0x38/0x50) from [<c039d92c>] (usb_stor_Bulk_transport+0x114/0x2d0)
[ 1356.096374] [<c039d92c>] (usb_stor_Bulk_transport+0x114/0x2d0) from [<c039d190>] (usb_stor_invoke_transport+0x34/0x3f4)
[ 1356.107238] [<c039d190>] (usb_stor_invoke_transport+0x34/0x3f4) from [<c039cc0c>] (usb_stor_transparent_scsi_command+0x18/0x1c)
[ 1356.118804] [<c039cc0c>] (usb_stor_transparent_scsi_command+0x18/0x1c) from [<c039f144>] (usb_stor_control_thread+0x190/0x28c)
[ 1356.130279] [<c039f144>] (usb_stor_control_thread+0x190/0x28c) from [<c00b97e0>] (kthread+0x98/0xa0)
[ 1356.139465] [<c00b97e0>] (kthread+0x98/0xa0) from [<c0064834>] (kernel_thread_exit+0x0/0x8)

Signed-off-by: Virupax Sadashivpetimath <virupax.sadashivpetimath@xxxxxxxxxxxxxx>
Acked-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
---
drivers/usb/musb/musb_core.c | 37 +++++++++++++++++++++++++++++++++++++
drivers/usb/musb/musb_host.c | 3 +++
2 files changed, 40 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index bb56a0e..fc6e990 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -414,6 +414,41 @@ static void musb_otg_timer_func(unsigned long data)
spin_unlock_irqrestore(&musb->lock, flags);
}

+void musb_handle_disconnect(struct musb *musb)
+{
+ int epnum, i;
+ struct urb *urb;
+ struct musb_hw_ep *hw_ep;
+ struct musb_qh *qh;
+ struct usb_hcd *hcd = musb_to_hcd(musb);
+
+ for (epnum = 0; epnum < musb->config->num_eps;
+ epnum++) {
+ hw_ep = musb->endpoints + epnum;
+ for (i = 0; i < 2; i++) {
+ if (hw_ep->in_qh == hw_ep->out_qh)
+ i++;
+ qh = (i == 0) ? hw_ep->in_qh : hw_ep->out_qh;
+
+ if (qh && qh->hep) {
+ qh->is_ready = 0;
+ while ((urb = next_urb(qh))) {
+ usb_hcd_unlink_urb_from_ep(hcd, urb);
+
+ spin_unlock(&musb->lock);
+ usb_hcd_giveback_urb(hcd, urb, 0);
+ spin_lock(&musb->lock);
+ }
+
+ qh->hep->hcpriv = NULL;
+ list_del(&qh->ring);
+ kfree(qh);
+ hw_ep->in_qh = hw_ep->out_qh = NULL;
+ }
+ }
+ }
+}
+
/*
* Stops the HNP transition. Caller must take care of locking.
*/
@@ -779,11 +814,13 @@ b_host:
otg_state_string(musb->xceiv->state),
MUSB_MODE(musb), devctl);
handled = IRQ_HANDLED;
+ musb->is_active = 0;

switch (musb->xceiv->state) {
case OTG_STATE_A_HOST:
case OTG_STATE_A_SUSPEND:
usb_hcd_resume_root_hub(musb_to_hcd(musb));
+ musb_handle_disconnect(musb);
musb_root_disconnect(musb);
if (musb->a_wait_bcon != 0)
musb_platform_try_idle(musb, jiffies
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 3df6a76..300786a 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -1921,6 +1921,9 @@ static int musb_schedule(
u8 txtype;
struct urb *urb = next_urb(qh);

+ if (!musb->is_active)
+ return -ENODEV;
+
/* use fixed hardware for control and bulk */
if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
head = &musb->control;
--
1.7.4.3

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