On Fri, 06 Jul 2012 14:34:24 -0400 Hal Rosenstock <h...@dev.mellanox.co.il> wrote:
> On 7/3/2012 12:55 PM, Ira Weiny wrote: > > > > Document the umad_recv length parameter better. > > > > Changes since V1: > > add comments from Hal > > > > Signed-off-by: Ira Weiny <wei...@llnl.gov> > > --- > > man/umad_recv.3 | 18 +++++++++++++++++- > > 1 files changed, 17 insertions(+), 1 deletions(-) > > > > diff --git a/man/umad_recv.3 b/man/umad_recv.3 > > index e1b2985..310d3d2 100644 > > --- a/man/umad_recv.3 > > +++ b/man/umad_recv.3 > > @@ -27,10 +27,26 @@ A negative > > makes the function block until a packet is received. A > > .I timeout_ms\fR > > parameter of zero indicates a non blocking read. > > + > > +.B Note > > +.I length > > +is a pointer to the length of the > > +.B data > > +portion of the umad buffer. This means that > > +.I umad > > +should point to a buffer at least umad_size() + > > +.I *length > > +bytes long. > > + > > +.B Note also > > +that > > +.I *length\fR > > +must be >= 256 bytes. > > This seems somewhat redundant to me as just above it says "should point > to a bugger that's at least umad_size() + *length bytes long. > > Also, if this remains, should "must be" be "should be" ? I _guess_ it _could_ be less than 256. However the specification states: "C13-3: The data payload (as used in Chapter 9: Transport Layer on page 233) for all MADs shall be exactly 256 bytes." Furthermore, the kernel checks to ensure that *length is > the first (or only) packet in the MAD transaction. While some Class/Attributes may allow for less "valid" data I'm not sure the kernel distinguishes that. Therefore, I think it is safer to just specify it. Don't you think? Ira > > > + > > .SH "RETURN VALUE" > > .B umad_recv() > > returns non negative receiving agentid on success, and a negative value on > > error as follows: > > - -EINVAL invalid port handle or agentid > > + -EINVAL invalid port handle or agentid or *length is less than the > > minimum > > Rather than just minimum, minimum support length might be clearer. > > -- Hal > > > -EIO receive operation failed > > -EWOULDBLOCK non blocking read can't be fulfilled > > .SH "SEE ALSO" > -- Ira Weiny Member of Technical Staff Lawrence Livermore National Lab 925-423-8008 wei...@llnl.gov -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html