Re: MCLGETI in if_msk.c

[christos%astron.com@localhost (Christos Zoulas)]

In article <trinity-df23ac7e-ee98-47b8-854b-ae7208449139-1509099592103@3c-app-mailcom-lxa13>,
Rocky Hotas <rockyhotas%post.com@localhost> wrote:
>Hi all!
>I am working to adapt the OpenBSD if_msk.c driver to NetBSD. If needed,
>these are my previous messages as a recap:
>
>http://mail-index.netbsd.org/tech-kern/2017/10/11/msg022430.html
>http://mail-index.netbsd.org/tech-kern/2017/10/11/msg022431.html
>
>OpenBSD made a huge modification to the `msk_newbuf' function with
>rev. 1.72:
>
>http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/sys/dev/pci/if_msk.c?rev=1.72&content-type=text/x-cvsweb-markup
>
>(see the commit comments for the details). They use the MCLGETI macro
>defined here:
>
>http://bxr.su/OpenBSD/sys/sys/mbuf.h#315
>
>In NetBSD this is a function, not a macro, and it is used only internally
>by these two drivers:
>
>src/sys/dev/ic/arn5008.c
>src/sys/dev/ic/arn9003.c
>
>Moreover,
>
>src/sys/dev/pci/if_iwn.c
>
>uses an improved version (maybe useful for the above files too in the
>future) of the same function.

I would not call it "improved" :-)

>The OpenBSD macro refers instead to the function `m_clget' defined here:
>
>http://bxr.su/OpenBSD/sys/kern/uipc_mbuf.c#348
>
>It is different, as regards the use of the pointer `struct pool *pp',
>the variable `caddr_t buf' and the flow itself of the code.
>Is there a way to adapt it to NetBSD even so? Or can NetBSD use a new
>function which could do the same?
>Bye!
 
OpenBSD:
                m = MCLGETI(NULL, M_DONTWAIT, NULL, MCLBYTES);
                if (m == NULL)
			goto fail;
NetBSD:
                MGETHDR(m, M_DONTWAIT, MT_DATA);
                if (m == NULL)
                        goto fail; 
                MCLGET(m, M_DONTWAIT);
                if (m->m_flags & M_EXT) == 0) {
		    	m_freem(m);
                        goto fail;
		}


It is not such a big deal :-) Or if you want to allocate a size other
than MCLBYTES (I am not sure if that works, perhaps we need a different
pool), use:
		_MCLGET(m, mcl_cache, size, M_DONTWAIT) 

It is ~trivial to add the macro in <sys/mbuf.h> and since we are porting
too many OpenBSD drivers, perhaps we should. But this should be discussed
in tech-net.

christos