[PATCH 1/2] misc: rtsx_usb: fix use of dma mapped buffer for usb bulk transfer

[Shuah Khan <skhan@linuxfoundation.org>]

rtsx_usb driver allocates coherent dma buffer for urb transfers.
This buffer is passed to usb_bulk_msg() and usb core tries to
map already mapped buffer running into a dma mapping error.

xhci_hcd 0000:01:00.0: rejecting DMA map of vmalloc memory
WARNING: CPU: 1 PID: 279 at include/linux/dma-mapping.h:326 usb_ hcd_map_urb_for_dma+0x7d6/0x820

...

xhci_map_urb_for_dma+0x291/0x4e0
usb_hcd_submit_urb+0x199/0x12b0
...
usb_submit_urb+0x3b8/0x9e0
usb_start_wait_urb+0xe3/0x2d0
usb_bulk_msg+0x115/0x240
rtsx_usb_transfer_data+0x185/0x1a8 [rtsx_usb]
rtsx_usb_send_cmd+0xbb/0x123 [rtsx_usb]
rtsx_usb_write_register+0x12c/0x143 [rtsx_usb]
rtsx_usb_probe+0x226/0x4b2 [rtsx_usb]

Fix it to use kmalloc() to get DMA-able memory region instead.

Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
---
 drivers/misc/cardreader/rtsx_usb.c | 13 +++++++------
 include/linux/rtsx_usb.h           |  1 -
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/cardreader/rtsx_usb.c b/drivers/misc/cardreader/rtsx_usb.c
index 1ef9b61077c4..e147cc8ab0fd 100644
--- a/drivers/misc/cardreader/rtsx_usb.c
+++ b/drivers/misc/cardreader/rtsx_usb.c
@@ -631,8 +631,7 @@ static int rtsx_usb_probe(struct usb_interface *intf,
 
 	ucr->pusb_dev = usb_dev;
 
-	ucr->iobuf = usb_alloc_coherent(ucr->pusb_dev, IOBUF_SIZE,
-			GFP_KERNEL, &ucr->iobuf_dma);
+	ucr->iobuf = kmalloc(IOBUF_SIZE, GFP_KERNEL);
 	if (!ucr->iobuf)
 		return -ENOMEM;
 
@@ -668,8 +667,9 @@ static int rtsx_usb_probe(struct usb_interface *intf,
 
 out_init_fail:
 	usb_set_intfdata(ucr->pusb_intf, NULL);
-	usb_free_coherent(ucr->pusb_dev, IOBUF_SIZE, ucr->iobuf,
-			ucr->iobuf_dma);
+	kfree(ucr->iobuf);
+	ucr->iobuf = NULL;
+	ucr->cmd_buf = ucr->rsp_buf = NULL;
 	return ret;
 }
 
@@ -682,8 +682,9 @@ static void rtsx_usb_disconnect(struct usb_interface *intf)
 	mfd_remove_devices(&intf->dev);
 
 	usb_set_intfdata(ucr->pusb_intf, NULL);
-	usb_free_coherent(ucr->pusb_dev, IOBUF_SIZE, ucr->iobuf,
-			ucr->iobuf_dma);
+	kfree(ucr->iobuf);
+	ucr->iobuf = NULL;
+	ucr->cmd_buf = ucr->rsp_buf = NULL;
 }
 
 #ifdef CONFIG_PM
diff --git a/include/linux/rtsx_usb.h b/include/linux/rtsx_usb.h
index 159729cffd8e..a07f7341ebc2 100644
--- a/include/linux/rtsx_usb.h
+++ b/include/linux/rtsx_usb.h
@@ -55,7 +55,6 @@ struct rtsx_ucr {
 	struct usb_interface	*pusb_intf;
 	struct usb_sg_request	current_sg;
 	unsigned char		*iobuf;
-	dma_addr_t		iobuf_dma;
 
 	struct timer_list	sg_timer;
 	struct mutex		dev_mutex;
-- 
2.34.1