On 2022-03-17, Alexander Bluhm wrote:
> On Thu, Mar 17, 2022 at 01:07:12AM +0100, Mark Kettenis wrote:
> > > Date: Thu, 17 Mar 2022 01:01:46 +0100 (CET)
> > > From: Mark Kettenis <mark.kette...@xs4all.nl>
> > >
> > > > Date: Thu, 17 Mar 2022 00:47:15 +0100
> > > > From: Alexander Bluhm <alexander.bl...@gmx.net>
> > > >
> > > > Hi,
> > > >
> > > > My previous atempt to add a mutex to in_pcb.h was reverted as it
> > > > broke userland build.
> > > >
> > > > Is the correct fix to include sys/mutex.h in every .c file that
> > > > includes netinet/in_pcb.h ? I made a release with it.
> > > > Or should I include sys/mutex.h in netinet/in_pcb.h ?
> > >
> > > Neither?
> > >
> > > It makes no sense to export the kernel mutex stuff to userland. Is
> > > there a way to avoid doing that by adding a bit for #ifdef _KERNEL?
> > ^^^^^^^^^
> > a bit more
>
> My diff adds struct mutex to struct inpcbtable. My later plan is
> to add a mutex also to struct inpcb.
>
> tcpbench uses libkvm to extract information from struct inpcbtable.
> netstat does that for struct inpcb. Also post mortem analysis from
> a kernel core dump is possible.
>
> I don't understand why userland must not know the size of struct
> mutex when tools where written to analyze these structs.
>
> Is there something special about struct mutex that should not shown
> to userland?
>
> Do you like this? Different structs for kernel and userland.
> I think this is confusing when used with libkvm.
>
> struct inpcbtable {
> TAILQ_HEAD(inpthead, inpcb) inpt_queue; /* [t] inet PCB queue */
> struct inpcbhead *inpt_hashtbl; /* [t] local and foreign hash
> */
> struct inpcbhead *inpt_lhashtbl; /* [t] local port hash */
> SIPHASH_KEY inpt_key, inpt_lkey; /* [t] secrets for hashes */
> u_long inpt_mask, inpt_lmask; /* [t] hash masks */
> int inpt_count, inpt_size; /* [t] queue count, hash size
> */
> #ifdef _KERNEL
> struct mutex inpt_mtx; /* protect queue and hash */
> #endif
> };
What if you add an #else case?
#ifdef _KERNEL
struct mutex inpt_mtx;
#else
char _mtxpad[8];
#endif
