> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Monday, March 21, 2016 1:29 AM > To: KY Srinivasan <kys@xxxxxxxxxxxxx> > Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; > jasowang@xxxxxxxxxx > Subject: Re: [PATCH 5/5] Drivers: hv: vmbus: Implement copy-free read APIs > > "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> writes: > > > Implement copy-free read APIs. > > > > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > > --- > > drivers/hv/ring_buffer.c | 55 > ++++++++++++++++++++++++++++++++++++++++++++++ > > include/linux/hyperv.h | 6 +++++ > > 2 files changed, 61 insertions(+), 0 deletions(-) > > > > diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c > > index c2c2b2e..c80e1f3 100644 > > --- a/drivers/hv/ring_buffer.c > > +++ b/drivers/hv/ring_buffer.c > > @@ -444,3 +444,58 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info > *inring_info, > > > > return ret; > > } > > + > > +/* > > + * In-place read functions. > > + */ > > +bool get_next_pkt_raw(struct vmbus_channel *channel, > > + struct vmpacket_descriptor **desc) > > I suggest we make these functions return pointers and use > ERR_PTR()/IS_ERR() when we need to return an error. Either we get a pointer to a descriptor or not; there is no other error here. I will change the signature accordingly. > > > +{ > > + struct hv_ring_buffer_info *ring_info = &channel->inbound; > > + u32 read_loc = ring_info->ring_buffer->read_index; > > + void *ring_buffer = hv_get_ring_buffer(ring_info); > > + struct vmpacket_descriptor *cur_desc; > > + u32 packetlen; > > + u32 dsize = ring_info->ring_datasize; > > + u32 bytes_avail_toread = hv_get_bytes_to_read(ring_info); > > + > > + if (bytes_avail_toread < sizeof(struct vmpacket_descriptor)) > > + return false; > > + > > + if ((read_loc + sizeof(*desc)) > dsize) > > + return false; > > + > > + cur_desc = ring_buffer + read_loc; > > + packetlen = cur_desc->len8 << 3; > > + > > + if ((read_loc + packetlen + 8) > (dsize - 1)) > > Could you please add a define for this '8'? Sure. K. Y _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
