[ 27/60] ALSA: 6fire: fix DMA issues with URB transfer_buffer usage

Greg Kroah-Hartman
2013-08-13T06:53:32Z

From: Jussi Kivilinna <jussi.kivilinna@iki.fi>

commit ddb6b5a964371e8e52e696b2b258bda144c8bd3f upstream.

Patch fixes 6fire not to use stack as URB transfer_buffer. URB buffers need to
be DMA-able, which stack is not. Furthermore, transfer_buffer should not be
allocated as part of larger device structure because DMA coherency issues and
patch fixes this issue too.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@iki.fi>
Tested-by: Torsten Schenk <torsten.schenk@zoho.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/usb/6fire/comm.c | 38 +++++++++++++++++++++++++++++++++-----
sound/usb/6fire/comm.h | 2 +-
2 files changed, 34 insertions(+), 6 deletions(-)

--- a/sound/usb/6fire/comm.c
+++ b/sound/usb/6fire/comm.c
@@ -110,19 +110,37 @@ static int usb6fire_comm_send_buffer(u8
static int usb6fire_comm_write8(struct comm_runtime *rt, u8 request,
u8 reg, u8 value)
{
- u8 buffer[13]; /* 13: maximum length of message */
+ u8 *buffer;
+ int ret;
+
+ /* 13: maximum length of message */
+ buffer = kmalloc(13, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;

usb6fire_comm_init_buffer(buffer, 0x00, request, reg, value, 0x00);
- return usb6fire_comm_send_buffer(buffer, rt->chip->dev);
+ ret = usb6fire_comm_send_buffer(buffer, rt->chip->dev);
+
+ kfree(buffer);
+ return ret;
}

static int usb6fire_comm_write16(struct comm_runtime *rt, u8 request,
u8 reg, u8 vl, u8 vh)
{
- u8 buffer[13]; /* 13: maximum length of message */
+ u8 *buffer;
+ int ret;
+
+ /* 13: maximum length of message */
+ buffer = kmalloc(13, GFP_KERNEL);
+ if (!buffer)
+ return -ENOMEM;

usb6fire_comm_init_buffer(buffer, 0x00, request, reg, vl, vh);
- return usb6fire_comm_send_buffer(buffer, rt->chip->dev);
+ ret = usb6fire_comm_send_buffer(buffer, rt->chip->dev);
+
+ kfree(buffer);
+ return ret;
}

int usb6fire_comm_init(struct sfire_chip *chip)
@@ -135,6 +153,12 @@ int usb6fire_comm_init(struct sfire_chip
if (!rt)
return -ENOMEM;

+ rt->receiver_buffer = kzalloc(COMM_RECEIVER_BUFSIZE, GFP_KERNEL);
+ if (!rt->receiver_buffer) {
+ kfree(rt);
+ return -ENOMEM;
+ }
+
urb = &rt->receiver;
rt->serial = 1;
rt->chip = chip;
@@ -153,6 +177,7 @@ int usb6fire_comm_init(struct sfire_chip
urb->interval = 1;
ret = usb_submit_urb(urb, GFP_KERNEL);
if (ret < 0) {
+ kfree(rt->receiver_buffer);
kfree(rt);
snd_printk(KERN_ERR PREFIX "cannot create comm data receiver.");
return ret;
@@ -171,6 +196,9 @@ void usb6fire_comm_abort(struct sfire_ch

void usb6fire_comm_destroy(struct sfire_chip *chip)
{
- kfree(chip->comm);
+ struct comm_runtime *rt = chip->comm;
+
+ kfree(rt->receiver_buffer);
+ kfree(rt);
chip->comm = NULL;
}
--- a/sound/usb/6fire/comm.h
+++ b/sound/usb/6fire/comm.h
@@ -24,7 +24,7 @@ struct comm_runtime {
struct sfire_chip *chip;

struct urb receiver;
- u8 receiver_buffer[COMM_RECEIVER_BUFSIZE];
+ u8 *receiver_buffer;

u8 serial; /* urb serial */