[PATCH v2 1/6] USB: serial: ch314: use usb_control_msg_recv() and usb_control_msg_send()
From: Himadri Pandya
Date: Sun Aug 01 2021 - 16:33:10 EST
usb_control_msg_send/recv are new wrapper functions for usb_control_msg()
that have proper error checks for short read/writes. These functions
can also accept data buffer on stack. Hence use these functions to have
more robust error checks, and to reduce kernel memory usage for usb
messages.
Signed-off-by: Himadri Pandya <himadrispandya@xxxxxxxxx>
---
Changes in v2:
- Fix callers of ch341_control_out() and ch341_control_in()
- Remove label "out"
- Remove an unnecessary assignment statement
---
drivers/usb/serial/ch341.c | 97 ++++++++++++--------------------------
1 file changed, 29 insertions(+), 68 deletions(-)
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 2db917eab799..c6f7ff9ca8ae 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -113,10 +113,10 @@ static int ch341_control_out(struct usb_device *dev, u8 request,
dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x)\n", __func__,
request, value, index);
- r = usb_control_msg(dev, usb_sndctrlpipe(dev, 0), request,
- USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
- value, index, NULL, 0, DEFAULT_TIMEOUT);
- if (r < 0)
+ r = usb_control_msg_send(dev, 0, request,
+ USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
+ value, index, NULL, 0, DEFAULT_TIMEOUT, GFP_KERNEL);
+ if (r)
dev_err(&dev->dev, "failed to send control message: %d\n", r);
return r;
@@ -131,23 +131,13 @@ static int ch341_control_in(struct usb_device *dev,
dev_dbg(&dev->dev, "%s - (%02x,%04x,%04x,%u)\n", __func__,
request, value, index, bufsize);
- r = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0), request,
- USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
- value, index, buf, bufsize, DEFAULT_TIMEOUT);
- if (r < (int)bufsize) {
- if (r >= 0) {
- dev_err(&dev->dev,
- "short control message received (%d < %u)\n",
- r, bufsize);
- r = -EIO;
- }
-
- dev_err(&dev->dev, "failed to receive control message: %d\n",
- r);
- return r;
- }
+ r = usb_control_msg_recv(dev, 0, request,
+ USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+ value, index, buf, bufsize, DEFAULT_TIMEOUT, GFP_KERNEL);
+ if (r)
+ dev_err(&dev->dev, "failed to receive control message: %d\n", r);
- return 0;
+ return r;
}
#define CH341_CLKRATE 48000000
@@ -287,23 +277,19 @@ static int ch341_set_handshake(struct usb_device *dev, u8 control)
static int ch341_get_status(struct usb_device *dev, struct ch341_private *priv)
{
const unsigned int size = 2;
- char *buffer;
+ u8 buffer[2];
int r;
unsigned long flags;
- buffer = kmalloc(size, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
r = ch341_control_in(dev, CH341_REQ_READ_REG, 0x0706, 0, buffer, size);
- if (r < 0)
+ if (r)
goto out;
spin_lock_irqsave(&priv->lock, flags);
priv->msr = (~(*buffer)) & CH341_BITS_MODEM_STAT;
spin_unlock_irqrestore(&priv->lock, flags);
-out: kfree(buffer);
+out:
return r;
}
@@ -312,21 +298,17 @@ out: kfree(buffer);
static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
{
const unsigned int size = 2;
- char *buffer;
+ u8 buffer[2];
int r;
- buffer = kmalloc(size, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
/* expect two bytes 0x27 0x00 */
r = ch341_control_in(dev, CH341_REQ_READ_VERSION, 0, 0, buffer, size);
- if (r < 0)
+ if (r)
goto out;
dev_dbg(&dev->dev, "Chip version: 0x%02x\n", buffer[0]);
r = ch341_control_out(dev, CH341_REQ_SERIAL_INIT, 0, 0);
- if (r < 0)
+ if (r)
goto out;
r = ch341_set_baudrate_lcr(dev, priv, priv->baud_rate, priv->lcr);
@@ -335,7 +317,7 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv)
r = ch341_set_handshake(dev, priv->mcr);
-out: kfree(buffer);
+out:
return r;
}
@@ -345,39 +327,23 @@ static int ch341_detect_quirks(struct usb_serial_port *port)
struct usb_device *udev = port->serial->dev;
const unsigned int size = 2;
unsigned long quirks = 0;
- char *buffer;
+ u8 buffer[2];
int r;
- buffer = kmalloc(size, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
-
/*
* A subset of CH34x devices does not support all features. The
* prescaler is limited and there is no support for sending a RS232
* break condition. A read failure when trying to set up the latter is
* used to detect these devices.
*/
- r = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), CH341_REQ_READ_REG,
- USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
- CH341_REG_BREAK, 0, buffer, size, DEFAULT_TIMEOUT);
+ r = usb_control_msg_recv(udev, 0, CH341_REQ_READ_REG,
+ USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
+ CH341_REG_BREAK, 0, &buffer, size, DEFAULT_TIMEOUT, GFP_KERNEL);
if (r == -EPIPE) {
dev_info(&port->dev, "break control not supported, using simulated break\n");
quirks = CH341_QUIRK_LIMITED_PRESCALER | CH341_QUIRK_SIMULATE_BREAK;
- r = 0;
- goto out;
- }
-
- if (r != size) {
- if (r >= 0)
- r = -EIO;
+ } else if (r)
dev_err(&port->dev, "failed to read break control: %d\n", r);
- goto out;
- }
-
- r = 0;
-out:
- kfree(buffer);
if (quirks) {
dev_dbg(&port->dev, "enabling quirk flags: 0x%02lx\n", quirks);
@@ -647,23 +613,19 @@ static void ch341_break_ctl(struct tty_struct *tty, int break_state)
struct ch341_private *priv = usb_get_serial_port_data(port);
int r;
uint16_t reg_contents;
- uint8_t *break_reg;
+ uint8_t break_reg[2];
if (priv->quirks & CH341_QUIRK_SIMULATE_BREAK) {
ch341_simulate_break(tty, break_state);
return;
}
- break_reg = kmalloc(2, GFP_KERNEL);
- if (!break_reg)
- return;
-
- r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
- ch341_break_reg, 0, break_reg, 2);
- if (r < 0) {
+ r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG, ch341_break_reg, 0,
+ break_reg, 2);
+ if (r) {
dev_err(&port->dev, "%s - USB control read error (%d)\n",
__func__, r);
- goto out;
+ return;
}
dev_dbg(&port->dev, "%s - initial ch341 break register contents - reg1: %x, reg2: %x\n",
__func__, break_reg[0], break_reg[1]);
@@ -681,11 +643,10 @@ static void ch341_break_ctl(struct tty_struct *tty, int break_state)
reg_contents = get_unaligned_le16(break_reg);
r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
ch341_break_reg, reg_contents);
- if (r < 0)
+ if (r)
dev_err(&port->dev, "%s - USB control write error (%d)\n",
__func__, r);
-out:
- kfree(break_reg);
+ return;
}
static int ch341_tiocmset(struct tty_struct *tty,
--
2.17.1