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usb: renesas_usbhs: modify spinlock method
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Current renesas_usbhs driver was using spin_trylock to avoid
dead lock / nest lock.
But acording to CONFIG_DEBUG_SPINLOCK, it is BUG under UP environment.
This patch add usbhsg_trylock to avoid this issue.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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Kuninori Morimoto authored and Greg Kroah-Hartman committed Apr 30, 2011
1 parent 409ba9e commit cb96632
Showing 1 changed file with 61 additions and 36 deletions.
97 changes: 61 additions & 36 deletions drivers/usb/renesas_usbhs/mod_gadget.c
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Original file line number Diff line number Diff line change
Expand Up @@ -118,6 +118,35 @@ struct usbhsg_recip_handle {
#define usbhsg_status_clr(gp, b) (gp->status &= ~b)
#define usbhsg_status_has(gp, b) (gp->status & b)

/*
* usbhsg_trylock
*
* This driver don't use spin_try_lock
* to avoid warning of CONFIG_DEBUG_SPINLOCK
*/
static spinlock_t *usbhsg_trylock(struct usbhsg_gpriv *gpriv,
unsigned long *flags)
{
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);

/* check spin lock status
* to avoid deadlock/nest */
if (spin_is_locked(lock))
return NULL;

spin_lock_irqsave(lock, *flags);

return lock;
}

static void usbhsg_unlock(spinlock_t *lock, unsigned long *flags)
{
if (!lock)
return;

spin_unlock_irqrestore(lock, *flags);
}

/*
* list push/pop
*/
Expand Down Expand Up @@ -159,9 +188,8 @@ static int __usbhsg_queue_handler(struct usbhsg_uep *uep, int prepare)
struct usbhsg_gpriv *gpriv = usbhsg_uep_to_gpriv(uep);
struct device *dev = usbhsg_gpriv_to_dev(gpriv);
struct usbhsg_request *ureq;
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);
spinlock_t *lock;
unsigned long flags;
int is_locked;
int ret = 0;

if (!uep->handler) {
Expand All @@ -179,7 +207,7 @@ static int __usbhsg_queue_handler(struct usbhsg_uep *uep, int prepare)
* - usb_request :: complete
*
* But the caller of this function need not care about spinlock.
* This function is using spin_trylock_irqsave for it.
* This function is using usbhsg_trylock for it.
* if "is_locked" is 1, this mean this function lock it.
* but if it is 0, this mean it is already under spin lock.
* see also
Expand All @@ -188,16 +216,16 @@ static int __usbhsg_queue_handler(struct usbhsg_uep *uep, int prepare)
*/

/****************** spin try lock *******************/
is_locked = spin_trylock_irqsave(lock, flags);
lock = usbhsg_trylock(gpriv, &flags);

ureq = usbhsg_queue_get(uep);
if (ureq) {
if (prepare)
ret = uep->handler->prepare(uep, ureq);
else
ret = uep->handler->try_run(uep, ureq);
}
if (is_locked)
spin_unlock_irqrestore(lock, flags);
usbhsg_unlock(lock, &flags);
/******************** spin unlock ******************/

return ret;
Expand Down Expand Up @@ -228,7 +256,7 @@ static void usbhsg_queue_pop(struct usbhsg_uep *uep,
* It mean "usb_ep_ops :: queue" which is using spinlock is called
* under spinlock.
*
* To avoid dead-lock, this driver is using spin_trylock.
* To avoid dead-lock, this driver is using usbhsg_trylock.
* CAUTION [*endpoint queue*]
* CAUTION [*queue handler*]
*/
Expand Down Expand Up @@ -811,7 +839,7 @@ static int usbhsg_ep_enable(struct usb_ep *ep,
struct usbhsg_gpriv *gpriv = usbhsg_uep_to_gpriv(uep);
struct usbhs_priv *priv = usbhsg_gpriv_to_priv(gpriv);
struct usbhs_pipe *pipe;
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);
spinlock_t *lock;
unsigned long flags;
int ret = -EIO;

Expand All @@ -823,7 +851,7 @@ static int usbhsg_ep_enable(struct usb_ep *ep,
return 0;

/******************** spin lock ********************/
spin_lock_irqsave(lock, flags);
lock = usbhsg_trylock(gpriv, &flags);

pipe = usbhs_pipe_malloc(priv, desc);
if (pipe) {
Expand All @@ -838,7 +866,8 @@ static int usbhsg_ep_enable(struct usb_ep *ep,

ret = 0;
}
spin_unlock_irqrestore(lock, flags);

usbhsg_unlock(lock, &flags);
/******************** spin unlock ******************/

return ret;
Expand All @@ -848,14 +877,16 @@ static int usbhsg_ep_disable(struct usb_ep *ep)
{
struct usbhsg_uep *uep = usbhsg_ep_to_uep(ep);
struct usbhsg_gpriv *gpriv = usbhsg_uep_to_gpriv(uep);
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);
spinlock_t *lock;
unsigned long flags;
int ret;

/******************** spin lock ********************/
spin_lock_irqsave(lock, flags);
lock = usbhsg_trylock(gpriv, &flags);

ret = usbhsg_pipe_disable(uep);
spin_unlock_irqrestore(lock, flags);

usbhsg_unlock(lock, &flags);
/******************** spin unlock ******************/

return ret;
Expand Down Expand Up @@ -890,10 +921,9 @@ static int usbhsg_ep_queue(struct usb_ep *ep, struct usb_request *req,
struct usbhsg_gpriv *gpriv = usbhsg_uep_to_gpriv(uep);
struct usbhsg_request *ureq = usbhsg_req_to_ureq(req);
struct usbhs_pipe *pipe = usbhsg_uep_to_pipe(uep);
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);
spinlock_t *lock;
unsigned long flags;
int ret = 0;
int is_locked;

/*
* CAUTION [*endpoint queue*]
Expand All @@ -904,7 +934,7 @@ static int usbhsg_ep_queue(struct usb_ep *ep, struct usb_request *req,
* it is already under spinlock on this driver.
* but it is called frm usb driver, this function should call spinlock.
*
* This function is using spin_trylock_irqsave to solve this issue.
* This function is using usbshg_trylock to solve this issue.
* if "is_locked" is 1, this mean this function lock it.
* but if it is 0, this mean it is already under spin lock.
* see also
Expand All @@ -913,7 +943,7 @@ static int usbhsg_ep_queue(struct usb_ep *ep, struct usb_request *req,
*/

/******************** spin lock ********************/
is_locked = spin_trylock_irqsave(lock, flags);
lock = usbhsg_trylock(gpriv, &flags);

/* param check */
if (usbhsg_is_not_connected(gpriv) ||
Expand All @@ -923,8 +953,7 @@ static int usbhsg_ep_queue(struct usb_ep *ep, struct usb_request *req,
else
usbhsg_queue_push(uep, ureq);

if (is_locked)
spin_unlock_irqrestore(lock, flags);
usbhsg_unlock(lock, &flags);
/******************** spin unlock ******************/

usbhsg_queue_prepare(uep);
Expand All @@ -937,9 +966,8 @@ static int usbhsg_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
struct usbhsg_uep *uep = usbhsg_ep_to_uep(ep);
struct usbhsg_request *ureq = usbhsg_req_to_ureq(req);
struct usbhsg_gpriv *gpriv = usbhsg_uep_to_gpriv(uep);
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);
spinlock_t *lock;
unsigned long flags;
int is_locked;

/*
* see
Expand All @@ -949,12 +977,11 @@ static int usbhsg_ep_dequeue(struct usb_ep *ep, struct usb_request *req)
*/

/******************** spin lock ********************/
is_locked = spin_trylock_irqsave(lock, flags);
lock = usbhsg_trylock(gpriv, &flags);

usbhsg_queue_pop(uep, ureq, -ECONNRESET);

if (is_locked)
spin_unlock_irqrestore(lock, flags);
usbhsg_unlock(lock, &flags);
/******************** spin unlock ******************/

return 0;
Expand All @@ -966,10 +993,9 @@ static int __usbhsg_ep_set_halt_wedge(struct usb_ep *ep, int halt, int wedge)
struct usbhs_pipe *pipe = usbhsg_uep_to_pipe(uep);
struct usbhsg_gpriv *gpriv = usbhsg_uep_to_gpriv(uep);
struct device *dev = usbhsg_gpriv_to_dev(gpriv);
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);
spinlock_t *lock;
unsigned long flags;
int ret = -EAGAIN;
int is_locked;

/*
* see
Expand All @@ -979,7 +1005,7 @@ static int __usbhsg_ep_set_halt_wedge(struct usb_ep *ep, int halt, int wedge)
*/

/******************** spin lock ********************/
is_locked = spin_trylock_irqsave(lock, flags);
lock = usbhsg_trylock(gpriv, &flags);
if (!usbhsg_queue_get(uep)) {

dev_dbg(dev, "set halt %d (pipe %d)\n",
Expand All @@ -998,8 +1024,7 @@ static int __usbhsg_ep_set_halt_wedge(struct usb_ep *ep, int halt, int wedge)
ret = 0;
}

if (is_locked)
spin_unlock_irqrestore(lock, flags);
usbhsg_unlock(lock, &flags);
/******************** spin unlock ******************/

return ret;
Expand Down Expand Up @@ -1038,11 +1063,11 @@ static int usbhsg_try_start(struct usbhs_priv *priv, u32 status)
struct usbhsg_uep *dcp = usbhsg_gpriv_to_dcp(gpriv);
struct usbhs_mod *mod = usbhs_mod_get_current(priv);
struct device *dev = usbhs_priv_to_dev(priv);
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);
spinlock_t *lock;
unsigned long flags;

/******************** spin lock ********************/
spin_lock_irqsave(lock, flags);
lock = usbhsg_trylock(gpriv, &flags);

/*
* enable interrupt and systems if ready
Expand Down Expand Up @@ -1083,7 +1108,7 @@ static int usbhsg_try_start(struct usbhs_priv *priv, u32 status)
usbhs_irq_callback_update(priv, mod);

usbhsg_try_start_unlock:
spin_unlock_irqrestore(lock, flags);
usbhsg_unlock(lock, &flags);
/******************** spin unlock ********************/

return 0;
Expand All @@ -1095,11 +1120,11 @@ static int usbhsg_try_stop(struct usbhs_priv *priv, u32 status)
struct usbhs_mod *mod = usbhs_mod_get_current(priv);
struct usbhsg_uep *dcp = usbhsg_gpriv_to_dcp(gpriv);
struct device *dev = usbhs_priv_to_dev(priv);
spinlock_t *lock = usbhsg_gpriv_to_lock(gpriv);
spinlock_t *lock;
unsigned long flags;

/******************** spin lock ********************/
spin_lock_irqsave(lock, flags);
lock = usbhsg_trylock(gpriv, &flags);

/*
* disable interrupt and systems if 1st try
Expand Down Expand Up @@ -1127,7 +1152,7 @@ static int usbhsg_try_stop(struct usbhs_priv *priv, u32 status)
usbhs_sys_function_ctrl(priv, 0);
usbhs_sys_usb_ctrl(priv, 0);

spin_unlock_irqrestore(lock, flags);
usbhsg_unlock(lock, &flags);
/******************** spin unlock ********************/

if (gpriv->driver &&
Expand All @@ -1139,7 +1164,7 @@ static int usbhsg_try_stop(struct usbhs_priv *priv, u32 status)
return 0;

usbhsg_try_stop_unlock:
spin_unlock_irqrestore(lock, flags);
usbhsg_unlock(lock, &flags);

return 0;
}
Expand Down

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