Re: [Linux-kernel-mentees] [PATCH 06/15] usb: serial: f81232: use usb_control_msg_recv() and usb_control_msg_send()
From: Johan Hovold <johan@kernel.org>
Date: 2020-12-04 09:49:55
Also in:
linux-usb, lkml
On Wed, Nov 04, 2020 at 12:16:54PM +0530, Himadri Pandya wrote:
quoted hunk ↗ jump to hunk
The new usb_control_msg_recv() and usb_control_msg_send() nicely wraps usb_control_msg() with proper error check. Hence use the wrappers instead of calling usb_control_msg() directly. Signed-off-by: Himadri Pandya <redacted> --- drivers/usb/serial/f81232.c | 88 ++++++++----------------------------- 1 file changed, 18 insertions(+), 70 deletions(-)diff --git a/drivers/usb/serial/f81232.c b/drivers/usb/serial/f81232.c index 0c7eacc630e0..78107feef8a8 100644 --- a/drivers/usb/serial/f81232.c +++ b/drivers/usb/serial/f81232.c@@ -139,71 +139,36 @@ static int calc_baud_divisor(speed_t baudrate, speed_t clockrate) static int f81232_get_register(struct usb_serial_port *port, u16 reg, u8 *val) { int status; - u8 *tmp; struct usb_device *dev = port->serial->dev; - tmp = kmalloc(sizeof(*val), GFP_KERNEL); - if (!tmp) - return -ENOMEM; - - status = usb_control_msg(dev, - usb_rcvctrlpipe(dev, 0), - F81232_REGISTER_REQUEST, - F81232_GET_REGISTER, - reg, - 0, - tmp, - sizeof(*val), - USB_CTRL_GET_TIMEOUT); - if (status != sizeof(*val)) { + status = usb_control_msg_recv(dev, 0, F81232_REGISTER_REQUEST, + F81232_GET_REGISTER, reg, 0, val, + sizeof(*val), USB_CTRL_GET_TIMEOUT, + GFP_KERNEL);
This driver use tabs for indentation consistently so please stick to that style. That should also amount to a smaller patch (and less noise in the logs, e.g. for git blame).
+ if (status) {
dev_err(&port->dev, "%s failed status: %d\n", __func__, status);
- if (status < 0)
- status = usb_translate_errors(status);
- else
- status = -EIO;
- } else {
- status = 0;
- *val = *tmp;
+ status = usb_translate_errors(status);
}
- kfree(tmp);
return status;
}quoted hunk ↗ jump to hunk
@@ -866,32 +831,16 @@ static int f81534a_ctrl_set_register(struct usb_interface *intf, u16 reg, struct usb_device *dev = interface_to_usbdev(intf); int retry = F81534A_ACCESS_REG_RETRY; int status; - u8 *tmp; - - tmp = kmemdup(val, size, GFP_KERNEL); - if (!tmp) - return -ENOMEM; while (retry--) { - status = usb_control_msg(dev, - usb_sndctrlpipe(dev, 0), - F81232_REGISTER_REQUEST, - F81232_SET_REGISTER, - reg, - 0, - tmp, - size, - USB_CTRL_SET_TIMEOUT); - if (status < 0) { + status = usb_control_msg_send(dev, 0, F81232_REGISTER_REQUEST, + F81232_SET_REGISTER, reg, 0, val, + size, USB_CTRL_SET_TIMEOUT, GFP_KERNEL); + if (status) { + /* Retry on error or short transfers */ status = usb_translate_errors(status); if (status == -EIO) continue;
So this now depends on the new helper returning an errno on short transfers which gets mapped to -EIO by usb_translate_errors(). This works currently (and with my suggested change to use -EREMOTEIO) but could possibly lead to subtle regressions later. I don't think we need to worry about it, but just wanted to highlight the kind of impact these changes can have. Note that this change also replaces a single memdup with a memdup+memcpy for each iteration. But as this helper is used rarely (e.g. probe, resume and disconnect), and hopefully the retries are exceptions, the overhead could be acceptable.
quoted hunk ↗ jump to hunk
- } else if (status != size) { - /* Retry on short transfers */ - status = -EIO; - continue; - } else { - status = 0; } break;@@ -902,7 +851,6 @@ static int f81534a_ctrl_set_register(struct usb_interface *intf, u16 reg, reg, status); } - kfree(tmp); return status; }
Johan _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees