Skip to content

Commit

Permalink
zd1211rw: use urb anchors for tx and fix tx-queue disabling
Browse files Browse the repository at this point in the history 
When stress testing AP-mode I hit OOPS when unpluging or rmmodding
driver.

It appears that when tx-queue is disabled, tx-urbs might be left pending.
These can cause ehci to call non-existing tx_urb_complete() (after rmmod)
or uninitialized/reseted private structure (after disconnect()). Add skb
queue for submitted packets and unlink pending urbs on zd_usb_disable_tx().

Part of the problem seems to be usb->free_urb_list that isn't always
working as it should, causing machine freeze when trying to free the list
in zd_usb_disable_tx(). Caching free urbs isn't what other drivers seem
to be doing (usbnet for example) so strip free_usb_list.

Patch makes tx-urb handling saner with use of urb anchors.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
  • Loading branch information
Jussi Kivilinna authored and John W. Linville committed Feb 4, 2011
1 parent 681d119 commit 78fc800
Show file tree
Hide file tree
Showing 2 changed files with 41 additions and 75 deletions.
108 changes: 37 additions & 71 deletions drivers/net/wireless/zd1211rw/zd_usb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -779,19 +779,20 @@ void zd_usb_disable_tx(struct zd_usb *usb)
{
struct zd_usb_tx *tx = &usb->tx;
unsigned long flags;
struct list_head *pos, *n;

atomic_set(&tx->enabled, 0);

/* kill all submitted tx-urbs */
usb_kill_anchored_urbs(&tx->submitted);

spin_lock_irqsave(&tx->lock, flags);
list_for_each_safe(pos, n, &tx->free_urb_list) {
list_del(pos);
usb_free_urb(list_entry(pos, struct urb, urb_list));
}
tx->enabled = 0;
WARN_ON(tx->submitted_urbs != 0);
tx->submitted_urbs = 0;
spin_unlock_irqrestore(&tx->lock, flags);

/* The stopped state is ignored, relying on ieee80211_wake_queues()
* in a potentionally following zd_usb_enable_tx().
*/
spin_unlock_irqrestore(&tx->lock, flags);
}

/**
Expand All @@ -807,63 +808,13 @@ void zd_usb_enable_tx(struct zd_usb *usb)
struct zd_usb_tx *tx = &usb->tx;

spin_lock_irqsave(&tx->lock, flags);
tx->enabled = 1;
atomic_set(&tx->enabled, 1);
tx->submitted_urbs = 0;
ieee80211_wake_queues(zd_usb_to_hw(usb));
tx->stopped = 0;
spin_unlock_irqrestore(&tx->lock, flags);
}

/**
* alloc_tx_urb - provides an tx URB
* @usb: a &struct zd_usb pointer
*
* Allocates a new URB. If possible takes the urb from the free list in
* usb->tx.
*/
static struct urb *alloc_tx_urb(struct zd_usb *usb)
{
struct zd_usb_tx *tx = &usb->tx;
unsigned long flags;
struct list_head *entry;
struct urb *urb;

spin_lock_irqsave(&tx->lock, flags);
if (list_empty(&tx->free_urb_list)) {
urb = usb_alloc_urb(0, GFP_ATOMIC);
goto out;
}
entry = tx->free_urb_list.next;
list_del(entry);
urb = list_entry(entry, struct urb, urb_list);
out:
spin_unlock_irqrestore(&tx->lock, flags);
return urb;
}

/**
* free_tx_urb - frees a used tx URB
* @usb: a &struct zd_usb pointer
* @urb: URB to be freed
*
* Frees the transmission URB, which means to put it on the free URB
* list.
*/
static void free_tx_urb(struct zd_usb *usb, struct urb *urb)
{
struct zd_usb_tx *tx = &usb->tx;
unsigned long flags;

spin_lock_irqsave(&tx->lock, flags);
if (!tx->enabled) {
usb_free_urb(urb);
goto out;
}
list_add(&urb->urb_list, &tx->free_urb_list);
out:
spin_unlock_irqrestore(&tx->lock, flags);
}

static void tx_dec_submitted_urbs(struct zd_usb *usb)
{
struct zd_usb_tx *tx = &usb->tx;
Expand Down Expand Up @@ -905,6 +856,16 @@ static void tx_urb_complete(struct urb *urb)
struct sk_buff *skb;
struct ieee80211_tx_info *info;
struct zd_usb *usb;
struct zd_usb_tx *tx;

skb = (struct sk_buff *)urb->context;
info = IEEE80211_SKB_CB(skb);
/*
* grab 'usb' pointer before handing off the skb (since
* it might be freed by zd_mac_tx_to_dev or mac80211)
*/
usb = &zd_hw_mac(info->rate_driver_data[0])->chip.usb;
tx = &usb->tx;

switch (urb->status) {
case 0:
Expand All @@ -922,20 +883,15 @@ static void tx_urb_complete(struct urb *urb)
goto resubmit;
}
free_urb:
skb = (struct sk_buff *)urb->context;
/*
* grab 'usb' pointer before handing off the skb (since
* it might be freed by zd_mac_tx_to_dev or mac80211)
*/
info = IEEE80211_SKB_CB(skb);
usb = &zd_hw_mac(info->rate_driver_data[0])->chip.usb;
zd_mac_tx_to_dev(skb, urb->status);
free_tx_urb(usb, urb);
usb_free_urb(urb);
tx_dec_submitted_urbs(usb);
return;
resubmit:
usb_anchor_urb(urb, &tx->submitted);
r = usb_submit_urb(urb, GFP_ATOMIC);
if (r) {
usb_unanchor_urb(urb);
dev_dbg_f(urb_dev(urb), "error resubmit urb %p %d\n", urb, r);
goto free_urb;
}
Expand All @@ -958,8 +914,14 @@ int zd_usb_tx(struct zd_usb *usb, struct sk_buff *skb)
int r;
struct usb_device *udev = zd_usb_to_usbdev(usb);
struct urb *urb;
struct zd_usb_tx *tx = &usb->tx;

urb = alloc_tx_urb(usb);
if (!atomic_read(&tx->enabled)) {
r = -ENOENT;
goto out;
}

urb = usb_alloc_urb(0, GFP_ATOMIC);
if (!urb) {
r = -ENOMEM;
goto out;
Expand All @@ -968,13 +930,16 @@ int zd_usb_tx(struct zd_usb *usb, struct sk_buff *skb)
usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
skb->data, skb->len, tx_urb_complete, skb);

usb_anchor_urb(urb, &tx->submitted);
r = usb_submit_urb(urb, GFP_ATOMIC);
if (r)
if (r) {
usb_unanchor_urb(urb);
goto error;
}
tx_inc_submitted_urbs(usb);
return 0;
error:
free_tx_urb(usb, urb);
usb_free_urb(urb);
out:
return r;
}
Expand Down Expand Up @@ -1005,9 +970,9 @@ static inline void init_usb_tx(struct zd_usb *usb)
{
struct zd_usb_tx *tx = &usb->tx;
spin_lock_init(&tx->lock);
tx->enabled = 0;
atomic_set(&tx->enabled, 0);
tx->stopped = 0;
INIT_LIST_HEAD(&tx->free_urb_list);
init_usb_anchor(&tx->submitted);
tx->submitted_urbs = 0;
}

Expand Down Expand Up @@ -1240,6 +1205,7 @@ static void disconnect(struct usb_interface *intf)
ieee80211_unregister_hw(hw);

/* Just in case something has gone wrong! */
zd_usb_disable_tx(usb);
zd_usb_disable_rx(usb);
zd_usb_disable_int(usb);

Expand Down
8 changes: 4 additions & 4 deletions drivers/net/wireless/zd1211rw/zd_usb.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -184,18 +184,18 @@ struct zd_usb_rx {

/**
* struct zd_usb_tx - structure used for transmitting frames
* @enabled: atomic enabled flag, indicates whether tx is enabled
* @lock: lock for transmission
* @free_urb_list: list of free URBs, contains all the URBs, which can be used
* @submitted: anchor for URBs sent to device
* @submitted_urbs: atomic integer that counts the URBs having sent to the
* device, which haven't been completed
* @enabled: enabled flag, indicates whether tx is enabled
* @stopped: indicates whether higher level tx queues are stopped
*/
struct zd_usb_tx {
atomic_t enabled;
spinlock_t lock;
struct list_head free_urb_list;
struct usb_anchor submitted;
int submitted_urbs;
int enabled;
int stopped;
};

Expand Down

0 comments on commit 78fc800

Please sign in to comment.