Messages in this thread |  | | Date | Sat, 12 Mar 2022 22:50:37 +0300 | Subject | Re: [PATCH] media: stkwebcam: move stk_camera_read_reg() scratch buffer to struct stk_camera | From | Pavel Skripkin <> |
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Hi Trix,
On 3/12/22 20:30, trix@redhat.com wrote: > From: Tom Rix <trix@redhat.com> > > In stk_camera_read_reg() a single byte buffer is alloc-ed and > freed on every function call. Since the size is known, > move the buffer to the struct stk_camera where it will be alloc-ed > and freed once. > > Signed-off-by: Tom Rix <trix@redhat.com> > --- > drivers/media/usb/stkwebcam/stk-webcam.c | 11 ++--------- > drivers/media/usb/stkwebcam/stk-webcam.h | 2 ++ > 2 files changed, 4 insertions(+), 9 deletions(-) > > diff --git a/drivers/media/usb/stkwebcam/stk-webcam.c b/drivers/media/usb/stkwebcam/stk-webcam.c > index 5b822214ccc5c..787edb3d47c23 100644 > --- a/drivers/media/usb/stkwebcam/stk-webcam.c > +++ b/drivers/media/usb/stkwebcam/stk-webcam.c > @@ -150,25 +150,18 @@ int stk_camera_write_reg(struct stk_camera *dev, u16 index, u8 value) > int stk_camera_read_reg(struct stk_camera *dev, u16 index, u8 *value) > { > struct usb_device *udev = dev->udev; > - unsigned char *buf; > int ret; > > - buf = kmalloc(sizeof(u8), GFP_KERNEL); > - if (!buf) > - return -ENOMEM; > - > ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0), > 0x00, > USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, > 0x00, > index, > - buf, > + &dev->read_reg_scratch, > sizeof(u8), > 500);
Wouldn't it be better to move to modern USB API like usb_control_msg_recv()?
This API does not require buffer to be allocated via kmalloc(), so you will be able to use value directly.
With regards, Pavel Skripkin
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