ALSA: 6fire: fix DMA issues with URB transfer_buffer usage

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.

Cc: stable@vger.kernel.org
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>

2 files changed, 34 insertions, 6 deletions

diff --git a/sound/usb/6fire/comm.c b/sound/usb/6fire/comm.c
index 9e6e3ffd86bb..23452ee617e1 100644
--- a/sound/usb/6fire/comm.c
+++ b/sound/usb/6fire/comm.c
@@ -110,19 +110,37 @@ static int usb6fire_comm_send_buffer(u8 *buffer, struct usb_device *dev)
 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 *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 *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_chip *chip)
 
 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;
 }
diff --git a/sound/usb/6fire/comm.h b/sound/usb/6fire/comm.h
index 6a0840b0dcff..780d5ed8e5d8 100644
--- 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 */