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Subject[PATCH 2/6 v2] [media] vp7045: get rid of on-stack dma buffers
Date
usb_control_msg initiates (and waits for completion of) a dma transfer using
the supplied buffer. That buffer thus has to be seperately allocated on
the heap.

In lib/dma_debug.c the function check_for_stack even warns about it:
WARNING: at lib/dma-debug.c:866 check_for_stack

Note: This change is tested to compile only, as I don't have the hardware.

Signed-off-by: Florian Mickler <florian@mickler.org>

---
[v2: pulled buffer access under the mutex]
drivers/media/dvb/dvb-usb/vp7045.c | 47 ++++++++++++++++++++++++++----------
1 files changed, 34 insertions(+), 13 deletions(-)
diff --git a/drivers/media/dvb/dvb-usb/vp7045.c b/drivers/media/dvb/dvb-usb/vp7045.c
index ab0ab3c..3db89e3 100644
--- a/drivers/media/dvb/dvb-usb/vp7045.c
+++ b/drivers/media/dvb/dvb-usb/vp7045.c
@@ -28,9 +28,9 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
int vp7045_usb_op(struct dvb_usb_device *d, u8 cmd, u8 *out, int outlen, u8 *in, int inlen, int msec)
{
int ret = 0;
- u8 inbuf[12] = { 0 }, outbuf[20] = { 0 };
+ u8 *buf = d->priv;

- outbuf[0] = cmd;
+ buf[0] = cmd;

if (outlen > 19)
outlen = 19;
@@ -38,19 +38,21 @@ int vp7045_usb_op(struct dvb_usb_device *d, u8 cmd, u8 *out, int outlen, u8 *in,
if (inlen > 11)
inlen = 11;

+ ret = mutex_lock_interruptible(&d->usb_mutex);
+ if (ret)
+ return ret;
+
if (out != NULL && outlen > 0)
- memcpy(&outbuf[1], out, outlen);
+ memcpy(&buf[1], out, outlen);

deb_xfer("out buffer: ");
- debug_dump(outbuf,outlen+1,deb_xfer);
+ debug_dump(buf, outlen+1, deb_xfer);

- if ((ret = mutex_lock_interruptible(&d->usb_mutex)))
- return ret;

if (usb_control_msg(d->udev,
usb_sndctrlpipe(d->udev,0),
TH_COMMAND_OUT, USB_TYPE_VENDOR | USB_DIR_OUT, 0, 0,
- outbuf, 20, 2000) != 20) {
+ buf, 20, 2000) != 20) {
err("USB control message 'out' went wrong.");
ret = -EIO;
goto unlock;
@@ -61,17 +63,17 @@ int vp7045_usb_op(struct dvb_usb_device *d, u8 cmd, u8 *out, int outlen, u8 *in,
if (usb_control_msg(d->udev,
usb_rcvctrlpipe(d->udev,0),
TH_COMMAND_IN, USB_TYPE_VENDOR | USB_DIR_IN, 0, 0,
- inbuf, 12, 2000) != 12) {
+ buf, 12, 2000) != 12) {
err("USB control message 'in' went wrong.");
ret = -EIO;
goto unlock;
}

deb_xfer("in buffer: ");
- debug_dump(inbuf,12,deb_xfer);
+ debug_dump(buf, 12, deb_xfer);

if (in != NULL && inlen > 0)
- memcpy(in,&inbuf[1],inlen);
+ memcpy(in, &buf[1], inlen);

unlock:
mutex_unlock(&d->usb_mutex);
@@ -222,8 +224,26 @@ static struct dvb_usb_device_properties vp7045_properties;
static int vp7045_usb_probe(struct usb_interface *intf,
const struct usb_device_id *id)
{
- return dvb_usb_device_init(intf, &vp7045_properties,
- THIS_MODULE, NULL, adapter_nr);
+ struct dvb_usb_device *d;
+ int ret = dvb_usb_device_init(intf, &vp7045_properties,
+ THIS_MODULE, &d, adapter_nr);
+ if (ret)
+ return ret;
+
+ d->priv = kmalloc(20, GFP_KERNEL);
+ if (!d->priv) {
+ dvb_usb_device_exit(intf);
+ return -ENOMEM;
+ }
+
+ return ret;
+}
+
+static void vp7045_usb_disconnect(struct usb_interface *intf)
+{
+ struct dvb_usb_device *d = usb_get_intfdata(intf);
+ kfree(d->priv);
+ dvb_usb_device_exit(intf);
}

static struct usb_device_id vp7045_usb_table [] = {
@@ -238,6 +258,7 @@ MODULE_DEVICE_TABLE(usb, vp7045_usb_table);
static struct dvb_usb_device_properties vp7045_properties = {
.usb_ctrl = CYPRESS_FX2,
.firmware = "dvb-usb-vp7045-01.fw",
+ .size_of_priv = sizeof(u8 *),

.num_adapters = 1,
.adapter = {
@@ -284,7 +305,7 @@ static struct dvb_usb_device_properties vp7045_properties = {
static struct usb_driver vp7045_usb_driver = {
.name = "dvb_usb_vp7045",
.probe = vp7045_usb_probe,
- .disconnect = dvb_usb_device_exit,
+ .disconnect = vp7045_usb_disconnect,
.id_table = vp7045_usb_table,
};

--
1.7.4.1


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