Quoting Dave Kilroy <kilr...@googlemail.com>:
On 16/02/2013 23:48, Larry Finger wrote:
On 02/16/2013 05:00 PM, Jussi Kivilinna wrote:
rtlwifi allocates both setup_packet and data buffer of control message urb,
using shared kmalloc in _usbctrl_vendorreq_async_write. Structure used for
allocating is:
struct {
u8 data[254];
struct usb_ctrlrequest dr;
};
Because 'struct usb_ctrlrequest' is __packed, setup packet is unaligned and
DMA mapping of both 'data' and 'dr' confuses ARM/sunxi, leading to memory
corruptions and freezes.
Patch changes setup packet to be allocated separately.
I am not crazy about the overhead in allocating two different
blocks for each output packet, but if it is necessary, then it has
to happen.
static int _usbctrl_vendorreq_async_write(struct usb_device
*udev, u8 request,
@@ -55,39 +59,47 @@ static int
_usbctrl_vendorreq_async_write(struct usb_device *udev, u8 request,
u8 reqtype;
struct usb_ctrlrequest *dr;
struct urb *urb;
- struct rtl819x_async_write_data {
- u8 data[REALTEK_USB_VENQT_MAX_BUF_SIZE];
- struct usb_ctrlrequest dr;
- } *buf;
If dr isn't at the appropriate alignment, wouldn't padding out the
data buffer achieve the same thing? Something like:
struct rtl819x_async_write_data {
- u8 data[REALTEK_USB_VENQT_MAX_BUF_SIZE];
+ u8 data[ALIGN(REALTEK_USB_VENQT_MAX_BUF_SIZE, ALIGNMENT)];
struct usb_ctrlrequest dr;
} *buf;
Where ALIGNMENT is whatever the required alignment is.
Either it needs to be ARCH_DMA_MINALIGN (need to use ifdefs) or
KMALLOC_MIN_ALIGN, which appearently is defined only for SLUB, not
SLAB or SLOB.
-Jussi
Dave.
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