[PATCH] rtlwifi: rtl8192cu: Change buffer allocation for synchronous reads
From: Larry Finger <hidden>
Date: 2012-07-11 19:37:30
In commit a7959c1, the USB part of rtlwifi was switched to convert _usb_read_sync() to using a preallocated buffer rather than one that has been acquired using kmalloc. Although this routine is named as though it were synchronous, there seem to be simultaneous users, and the selection of the index to the data buffer is not multi-user safe. This situation is addressed by adding a new spinlock. The routine cannot sleep, thus a mutex is not allowed. Signed-off-by: Larry Finger <redacted> Cc: Stable <redacted> --- John, This patch needs to be applied to stable; however, I would prefer that it resides in -next for a while, thus push it for 3.6. Larry --- Index: wireless-testing/drivers/net/wireless/rtlwifi/usb.c ===================================================================
--- wireless-testing.orig/drivers/net/wireless/rtlwifi/usb.c
+++ wireless-testing/drivers/net/wireless/rtlwifi/usb.c@@ -131,15 +131,19 @@ static u32 _usb_read_sync(struct rtl_pri u8 request; u16 wvalue; u16 index; - __le32 *data = &rtlpriv->usb_data[rtlpriv->usb_data_index]; + __le32 *data; + unsigned long flags; + spin_lock_irqsave(&rtlpriv->locks.usb_lock, flags); + if (++rtlpriv->usb_data_index >= RTL_USB_MAX_RX_COUNT) + rtlpriv->usb_data_index = 0; + data = &rtlpriv->usb_data[rtlpriv->usb_data_index]; + spin_unlock_irqrestore(&rtlpriv->locks.usb_lock, flags); request = REALTEK_USB_VENQT_CMD_REQ; index = REALTEK_USB_VENQT_CMD_IDX; /* n/a */ wvalue = (u16)addr; _usbctrl_vendorreq_sync_read(udev, request, wvalue, index, data, len); - if (++rtlpriv->usb_data_index >= RTL_USB_MAX_RX_COUNT) - rtlpriv->usb_data_index = 0; return le32_to_cpu(*data); }
@@ -951,6 +955,10 @@ int __devinit rtl_usb_probe(struct usb_i GFP_KERNEL); if (!rtlpriv->usb_data) return -ENOMEM; + + /* this spin lock must be initialized early */ + spin_lock_init(&rtlpriv->locks.usb_lock); + rtlpriv->usb_data_index = 0; init_completion(&rtlpriv->firmware_loading_complete); SET_IEEE80211_DEV(hw, &intf->dev);
Index: wireless-testing/drivers/net/wireless/rtlwifi/wifi.h ===================================================================
--- wireless-testing.orig/drivers/net/wireless/rtlwifi/wifi.h
+++ wireless-testing/drivers/net/wireless/rtlwifi/wifi.h@@ -1555,6 +1555,7 @@ struct rtl_locks { spinlock_t rf_ps_lock; spinlock_t rf_lock; spinlock_t waitq_lock; + spinlock_t usb_lock; /*Dual mac*/ spinlock_t cck_and_rw_pagea_lock;