Re: [PATCH] usb:serial: Add Fintek F81532/534 driver

[Ji-Ze Hong (Peter Hong)]

Hi Alan,

One Thousand Gnomes 於 2016/7/29 下午 08:48 寫道:

O

+static int f81534_set_normal_register(struct usb_device *dev, u16 reg, u8 data)
+{
+       size_t count = F81534_USB_MAX_RETRY;
+       int status;
+       u8 *tmp;
+
+       tmp = kmalloc(sizeof(u8), GFP_KERNEL);
+       if (!tmp)
+               return -ENOMEM;

You end up doing huge numbers of tiny allocation and frees in some of the
code paths. I think it would be better to allocate them at a higher level
as they are not that cheap on CPU time.

+static int f81534_read_data(struct usb_serial *usbserial, u32 address,
+                               size_t size, unsigned char *buf)
+{

Is a particularly good example - you do 4 mallocs plus two per byte of
data.

I'll re-factor the newest V9 patch with your suggestion. To malloc a
byte within usb_serial privates, and make a mutex to protect it.

I'll send it as V10 when I tested it.

Thanks for your suggestion.
--
With Best Regards,
Peter Hong