On Tue, Oct 23, 2012 at 4:57 PM, Ezequiel Garcia <elezegarcia@xxxxxxxxx> wrote: > This kind of memcpy() is error-prone. Its replacement with a struct > assignment is prefered because it's type-safe and much easier to read. > > Found by coccinelle. Hand patched and reviewed. > Tested by compilation only. > > A simplified version of the semantic match that finds this problem is as > follows: (http://coccinelle.lip6.fr/) > > // <smpl> > @@ > identifier struct_name; > struct struct_name to; > struct struct_name from; > expression E; > @@ > -memcpy(&(to), &(from), E); > +to = from; > // </smpl> > > Signed-off-by: Peter Senna Tschudin <peter.senna@xxxxxxxxx> > Signed-off-by: Ezequiel Garcia <elezegarcia@xxxxxxxxx> > --- > drivers/media/usb/sn9c102/sn9c102_core.c | 4 ++-- > 1 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/media/usb/sn9c102/sn9c102_core.c b/drivers/media/usb/sn9c102/sn9c102_core.c > index 5bfc8e2..4cae6f8 100644 > --- a/drivers/media/usb/sn9c102/sn9c102_core.c > +++ b/drivers/media/usb/sn9c102/sn9c102_core.c > @@ -2824,7 +2824,7 @@ sn9c102_vidioc_querybuf(struct sn9c102_device* cam, void __user * arg) > b.index >= cam->nbuffers || cam->io != IO_MMAP) > return -EINVAL; > > - memcpy(&b, &cam->frame[b.index].buf, sizeof(b)); > + b = cam->frame[b.index].buf; > > if (cam->frame[b.index].vma_use_count) > b.flags |= V4L2_BUF_FLAG_MAPPED; > @@ -2927,7 +2927,7 @@ sn9c102_vidioc_dqbuf(struct sn9c102_device* cam, struct file* filp, > > f->state = F_UNUSED; > > - memcpy(&b, &f->buf, sizeof(b)); > + b = f->buf; > if (f->vma_use_count) > b.flags |= V4L2_BUF_FLAG_MAPPED; > Andy: you got me thinking on performance. Most patches are initialization or setup code. Here we patch a xxx_vidioc_dqbuf() function. Is this a speed sensitive path? I still think this change can't hurt performance, but I may be wrong! Ezequiel -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
