Char/Misc driver fixes for 5.19-rc6

Here are 4 small char/misc driver fixes for 5.19-rc6 to resolve some
 reported issues.  They only affect 2 drivers:
 	- rtsx_usb: fix for of-reported DMA warning error, the driver
 	  was handling memory buffers in odd ways, it has now been fixed
 	  up to be much simpler and correct by Shuah.
 	- at25 eeprom driver bugfix for reported problem
 
 All of these have been in linux-next for a week with no reported
 problems.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'char-misc-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc

Pull char/misc driver fixes from Greg KH:
 "Here are four small char/misc driver fixes for 5.19-rc6 to resolve
  some reported issues. They only affect two drivers:

   - rtsx_usb: fix for of-reported DMA warning error, the driver was
     handling memory buffers in odd ways, it has now been fixed up to be
     much simpler and correct by Shuah.

   - at25 eeprom driver bugfix for reported problem

  All of these have been in linux-next for a week with no reported
  problems"

* tag 'char-misc-5.19-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  misc: rtsx_usb: set return value in rsp_buf alloc err path
  misc: rtsx_usb: use separate command and response buffers
  misc: rtsx_usb: fix use of dma mapped buffer for usb bulk transfer
  eeprom: at25: Rework buggy read splitting

drivers/misc/cardreader/rtsx_usb.c

@@ -631,16 +631,20 @@ 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);
-	if (!ucr->iobuf)
+	ucr->cmd_buf = kmalloc(IOBUF_SIZE, GFP_KERNEL);
+	if (!ucr->cmd_buf)
 		return -ENOMEM;
 
+	ucr->rsp_buf = kmalloc(IOBUF_SIZE, GFP_KERNEL);
+	if (!ucr->rsp_buf) {
+		ret = -ENOMEM;
+		goto out_free_cmd_buf;
+	}
+
 	usb_set_intfdata(intf, ucr);
 
 	ucr->vendor_id = id->idVendor;
 	ucr->product_id = id->idProduct;
-	ucr->cmd_buf = ucr->rsp_buf = ucr->iobuf;
 
 	mutex_init(&ucr->dev_mutex);
 
@@ -668,8 +672,11 @@ 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->rsp_buf);
+	ucr->rsp_buf = NULL;
+out_free_cmd_buf:
+	kfree(ucr->cmd_buf);
+	ucr->cmd_buf = NULL;
 	return ret;
 }
 
@@ -682,8 +689,12 @@ 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->cmd_buf);
+	ucr->cmd_buf = NULL;
+
+	kfree(ucr->rsp_buf);
+	ucr->rsp_buf = NULL;
 }
 
 #ifdef CONFIG_PM

drivers/misc/eeprom/at25.c

@@ -80,10 +80,9 @@ static int at25_ee_read(void *priv, unsigned int offset,
 	struct at25_data *at25 = priv;
 	char *buf = val;
 	size_t max_chunk = spi_max_transfer_size(at25->spi);
-	size_t num_msgs = DIV_ROUND_UP(count, max_chunk);
-	size_t nr_bytes = 0;
-	unsigned int msg_offset;
-	size_t msg_count;
+	unsigned int msg_offset = offset;
+	size_t bytes_left = count;
+	size_t segment;
 	u8			*cp;
 	ssize_t			status;
 	struct spi_transfer	t[2];
@@ -97,9 +96,8 @@ static int at25_ee_read(void *priv, unsigned int offset,
 	if (unlikely(!count))
 		return -EINVAL;
 
-	msg_offset = (unsigned int)offset;
-	msg_count = min(count, max_chunk);
-	while (num_msgs) {
+	do {
+		segment = min(bytes_left, max_chunk);
 		cp = at25->command;
 
 		instr = AT25_READ;
@@ -131,8 +129,8 @@ static int at25_ee_read(void *priv, unsigned int offset,
 		t[0].len = at25->addrlen + 1;
 		spi_message_add_tail(&t[0], &m);
 
-		t[1].rx_buf = buf + nr_bytes;
-		t[1].len = msg_count;
+		t[1].rx_buf = buf;
+		t[1].len = segment;
 		spi_message_add_tail(&t[1], &m);
 
 		status = spi_sync(at25->spi, &m);
@@ -142,10 +140,10 @@ static int at25_ee_read(void *priv, unsigned int offset,
 		if (status)
 			return status;
 
-		--num_msgs;
-		msg_offset += msg_count;
-		nr_bytes += msg_count;
-	}
+		msg_offset += segment;
+		buf += segment;
+		bytes_left -= segment;
+	} while (bytes_left > 0);
 
 	dev_dbg(&at25->spi->dev, "read %zu bytes at %d\n",
 		count, offset);
@@ -229,7 +227,7 @@ static int at25_ee_write(void *priv, unsigned int off, void *val, size_t count)
 	do {
 		unsigned long	timeout, retries;
 		unsigned	segment;
-		unsigned	offset = (unsigned) off;
+		unsigned	offset = off;
 		u8		*cp = bounce;
 		int		sr;
 		u8		instr;

include/linux/rtsx_usb.h

@@ -54,8 +54,6 @@ struct rtsx_ucr {
 	struct usb_device	*pusb_dev;
 	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;