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rtlwifi: Preallocate USB read buffers and eliminate kalloc in read routine

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The current version of rtlwifi for USB operations uses kmalloc to
acquire a 32-bit buffer for each read of the device. When
_usb_read_sync() is called with the rcu_lock held, the result is
a "sleeping function called from invalid context" BUG. This is
reported for two cases in https://bugzilla.kernel.org/show_bug.cgi?id=42775.
The first case has the lock originating from within rtlwifi and could
be fixed by rearranging the locking; however, the second originates from
within mac80211. The kmalloc() call is removed from _usb_read_sync()
by creating a ring buffer pointer in the private area and
allocating the buffer data in the probe routine.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.kernel.org> [This version good for 3.3+ - different patch for 3.2 - 2.6.39]
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Larry Finger 2012-03-19 15:44:31 -05:00 committed by John W. Linville
parent 292c41acdd
commit 30899cc6ab
2 changed files with 21 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
drivers/net/wireless/rtlwifi/usb.c
View File

@ -124,46 +124,38 @@ static int _usbctrl_vendorreq_sync_read(struct usb_device *udev, u8 request,
return status;
}
static u32 _usb_read_sync(struct usb_device *udev, u32 addr, u16 len)
static u32 _usb_read_sync(struct rtl_priv *rtlpriv, u32 addr, u16 len)
{
struct device *dev = rtlpriv->io.dev;
struct usb_device *udev = to_usb_device(dev);
u8 request;
u16 wvalue;
u16 index;
u32 *data;
u32 ret;
__le32 *data = &rtlpriv->usb_data[rtlpriv->usb_data_index];
data = kmalloc(sizeof(u32), GFP_KERNEL);
if (!data)
return -ENOMEM;
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);
ret = le32_to_cpu(*data);
kfree(data);
return ret;
if (++rtlpriv->usb_data_index >= RTL_USB_MAX_RX_COUNT)
rtlpriv->usb_data_index = 0;
return le32_to_cpu(*data);
}
static u8 _usb_read8_sync(struct rtl_priv *rtlpriv, u32 addr)
{
struct device *dev = rtlpriv->io.dev;
return (u8)_usb_read_sync(to_usb_device(dev), addr, 1);
return (u8)_usb_read_sync(rtlpriv, addr, 1);
}
static u16 _usb_read16_sync(struct rtl_priv *rtlpriv, u32 addr)
{
struct device *dev = rtlpriv->io.dev;
return (u16)_usb_read_sync(to_usb_device(dev), addr, 2);
return (u16)_usb_read_sync(rtlpriv, addr, 2);
}
static u32 _usb_read32_sync(struct rtl_priv *rtlpriv, u32 addr)
{
struct device *dev = rtlpriv->io.dev;
return _usb_read_sync(to_usb_device(dev), addr, 4);
return _usb_read_sync(rtlpriv, addr, 4);
}
static void _usb_write_async(struct usb_device *udev, u32 addr, u32 val,
@ -955,6 +947,11 @@ int __devinit rtl_usb_probe(struct usb_interface *intf,
return -ENOMEM;
}
rtlpriv = hw->priv;
rtlpriv->usb_data = kzalloc(RTL_USB_MAX_RX_COUNT * sizeof(u32),
GFP_KERNEL);
if (!rtlpriv->usb_data)
return -ENOMEM;
rtlpriv->usb_data_index = 0;
init_completion(&rtlpriv->firmware_loading_complete);
SET_IEEE80211_DEV(hw, &intf->dev);
udev = interface_to_usbdev(intf);
@ -1025,6 +1022,7 @@ void rtl_usb_disconnect(struct usb_interface *intf)
/* rtl_deinit_rfkill(hw); */
rtl_usb_deinit(hw);
rtl_deinit_core(hw);
kfree(rtlpriv->usb_data);
rtlpriv->cfg->ops->deinit_sw_leds(hw);
rtlpriv->cfg->ops->deinit_sw_vars(hw);
_rtl_usb_io_handler_release(hw);

6
drivers/net/wireless/rtlwifi/wifi.h
View File

@ -67,7 +67,7 @@
#define QOS_QUEUE_NUM 4
#define RTL_MAC80211_NUM_QUEUE 5
#define REALTEK_USB_VENQT_MAX_BUF_SIZE 254
#define RTL_USB_MAX_RX_COUNT 100
#define QBSS_LOAD_SIZE 5
#define MAX_WMMELE_LENGTH 64
@ -1629,6 +1629,10 @@ struct rtl_priv {
interface or hardware */
unsigned long status;
/* data buffer pointer for USB reads */
__le32 *usb_data;
int usb_data_index;
/*This must be the last item so
that it points to the data allocated
beyond this structure like: