On Wed, Jun 12, 2019 at 11:53:03AM +0200, Lorenzo Bianconi wrote: > > On Fri, May 31, 2019 at 11:38:23AM +0200, Lorenzo Bianconi wrote: > > [...] > > > > } > > > > > > urb->num_sgs = max_t(int, i, urb->num_sgs); > > > - urb->transfer_buffer_length = urb->num_sgs * q->buf_size, > > > + urb->transfer_buffer_length = urb->num_sgs * data_size; > > > sg_init_marker(urb->sg, urb->num_sgs); > > > > > > return i ? : -ENOMEM; > > > @@ -611,8 +611,12 @@ static int mt76u_alloc_rx(struct mt76_dev *dev) > > > if (!q->entry) > > > return -ENOMEM; > > > > > > - q->buf_size = dev->usb.sg_en ? MT_RX_BUF_SIZE : PAGE_SIZE; > > > + if (dev->usb.sg_en) > > > + q->buf_size = MT_BUF_WITH_OVERHEAD(MT_RX_BUF_SIZE); > > > > I strongly recommend to not doing this. While this should work > > in theory creating buffer with size of 2k + some bytes might > > trigger various bugs in dma mapping or other low level code. > > even in practice actually :)
I wouldn't be sure about this. It's not common to have buffers of such size and crossing pages boundaries. It really can trigger nasty bugs on various IOMMU drivers. > but we can be more cautious since probably copying > the first 128B will not make any difference Not sure if I understand what you mean. > > And skb_shered_info is needed only in first buffer IIUC. > > > > Also this patch seems to make first patch unnecessary except for > > non sg_en case (in which I think rx AMSDU is broken anyway), > > so I would prefer just to apply first patch. > > I do not think rx AMSDU is broken for non sg_en case since the max rx value > allowed should be 3839 IIRC and we alloc one page in this case If that's the case we should be fine, but then I do not understand why we allocate 8*2k buffers for sg_en case, isn't that AP can sent AMSDU frame 16k big? Stanislaw
