Messages in this thread | | | Subject | Re: [PATCH] usb:serial: Add Fintek F81532/534 driver | From | "Ji-Ze Hong (Peter Hong)" <> | Date | Thu, 4 Aug 2016 14:25:24 +0800 |
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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
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