Commit 7e4c7947 authored by Fabio M. De Francesco's avatar Fabio M. De Francesco Committed by Greg Kroah-Hartman
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staging: r8188eu: Use a Mutex instead of a binary Semaphore 



Use a Mutex instead of a binary Semaphore for the purpose of enforcing
mutual exclusive access to the "pwrctrl_priv" structure.

Mutexes are sleeping locks similar to Semaphores with a 'count' of one
(like binary Semaphores), however they have a simpler interface, more
efficient performance, and additional constraints.

There is no change in the logic of the new code; however it is more
simple because it gets rid of four unnecessary wrappers:
_init_pwrlock(), _enter_pwrlock(),_exit_pwrlock(), _rtw_down_sema().

Actually, there is a change in the state in which the code waits for
acquiring locks, because it makes it in an uninterruptible state
(instead the old code used down_interruptibe()). Interruptible
waits are neither required nor wanted in this driver.

Tested with ASUSTek Computer, Inc. Realtek 8188EUS [USB-N10 Nano].

Acked-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: default avatarFabio M. De Francesco <fmdefrancesco@gmail.com>
Link: https://lore.kernel.org/r/20211022171917.24363-1-fmdefrancesco@gmail.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 75c5e966

drivers/staging/r8188eu/core/rtw_pwrctrl.c

+5 −5
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ void ips_enter(struct adapter *padapter) 
		return;

	}



	_enter_pwrlock(&pwrpriv->lock);

	mutex_lock(&pwrpriv->lock);



	pwrpriv->bips_processing = true;
@@ -42,7 +42,7 @@ void ips_enter(struct adapter *padapter) 
	}

	pwrpriv->bips_processing = false;



	_exit_pwrlock(&pwrpriv->lock);

	mutex_unlock(&pwrpriv->lock);

}



int ips_leave(struct adapter *padapter)
@@ -53,7 +53,7 @@ int ips_leave(struct adapter *padapter) 
	int result = _SUCCESS;

	int keyid;



	_enter_pwrlock(&pwrpriv->lock);

	mutex_lock(&pwrpriv->lock);



	if ((pwrpriv->rf_pwrstate == rf_off) && (!pwrpriv->bips_processing)) {

		pwrpriv->bips_processing = true;
@@ -87,7 +87,7 @@ int ips_leave(struct adapter *padapter) 
		pwrpriv->bpower_saving = false;

	}



	_exit_pwrlock(&pwrpriv->lock);

	mutex_unlock(&pwrpriv->lock);



	return result;

}
@@ -337,7 +337,7 @@ void rtw_init_pwrctrl_priv(struct adapter *padapter) 
{

	struct pwrctrl_priv *pwrctrlpriv = &padapter->pwrctrlpriv;



	_init_pwrlock(&pwrctrlpriv->lock);

	mutex_init(&pwrctrlpriv->lock);

	pwrctrlpriv->rf_pwrstate = rf_on;

	pwrctrlpriv->ips_enter_cnts = 0;

	pwrctrlpriv->ips_leave_cnts = 0;

drivers/staging/r8188eu/include/osdep_service.h

+0 −2
Original line number Diff line number Diff line
@@ -141,8 +141,6 @@ extern unsigned char RSN_TKIP_CIPHER[4]; 


void *rtw_malloc2d(int h, int w, int size);



u32  _rtw_down_sema(struct semaphore *sema);



#define rtw_init_queue(q)					\

	do {							\

		INIT_LIST_HEAD(&((q)->queue));			\

drivers/staging/r8188eu/include/rtw_pwrctrl.h

+1 −16
Original line number Diff line number Diff line
@@ -27,21 +27,6 @@ enum power_mgnt { 
	PS_MODE_NUM

};



static inline void _init_pwrlock(struct semaphore  *plock)

{

	sema_init(plock, 1);

}



static inline void _enter_pwrlock(struct semaphore  *plock)

{

	_rtw_down_sema(plock);

}



static inline void _exit_pwrlock(struct semaphore  *plock)

{

	up(plock);

}



#define LPS_DELAY_TIME	1*HZ /*  1 sec */



/*  RF state. */
@@ -60,7 +45,7 @@ enum { /* for ips_mode */ 
};



struct pwrctrl_priv {

	struct semaphore lock;

	struct mutex lock; /* Mutex used to protect struct pwrctrl_priv */



	u8	pwr_mode;

	u8	smart_ps;

drivers/staging/r8188eu/os_dep/osdep_service.c

+0 −8
Original line number Diff line number Diff line
@@ -42,14 +42,6 @@ Otherwise, there will be racing condition. 
Caller must check if the list is empty before calling rtw_list_delete

*/



u32 _rtw_down_sema(struct semaphore *sema)

{

	if (down_interruptible(sema))

		return _FAIL;

	else

		return _SUCCESS;

}



inline u32 rtw_systime_to_ms(u32 systime)

{

	return systime * 1000 / HZ;

drivers/staging/r8188eu/os_dep/usb_intf.c

+4 −4
Original line number Diff line number Diff line
@@ -234,7 +234,7 @@ static int rtw_suspend(struct usb_interface *pusb_intf, pm_message_t message) 
	rtw_cancel_all_timer(padapter);

	LeaveAllPowerSaveMode(padapter);



	_enter_pwrlock(&pwrpriv->lock);

	mutex_lock(&pwrpriv->lock);

	/* s1. */

	if (pnetdev) {

		netif_carrier_off(pnetdev);
@@ -263,7 +263,7 @@ static int rtw_suspend(struct usb_interface *pusb_intf, pm_message_t message) 
	rtw_free_network_queue(padapter, true);



	rtw_dev_unload(padapter);

	_exit_pwrlock(&pwrpriv->lock);

	mutex_unlock(&pwrpriv->lock);



	if (check_fwstate(pmlmepriv, _FW_UNDER_SURVEY))

		rtw_indicate_scan_done(padapter, 1);
@@ -292,7 +292,7 @@ static int rtw_resume(struct usb_interface *pusb_intf) 
	pnetdev = padapter->pnetdev;

	pwrpriv = &padapter->pwrctrlpriv;



	_enter_pwrlock(&pwrpriv->lock);

	mutex_lock(&pwrpriv->lock);

	rtw_reset_drv_sw(padapter);

	if (pwrpriv)

		pwrpriv->bkeepfwalive = false;
@@ -304,7 +304,7 @@ static int rtw_resume(struct usb_interface *pusb_intf) 
	netif_device_attach(pnetdev);

	netif_carrier_on(pnetdev);



	_exit_pwrlock(&pwrpriv->lock);

	mutex_unlock(&pwrpriv->lock);



	if (padapter->pid[1] != 0) {

		DBG_88E("pid[1]:%d\n", padapter->pid[1]);