On 20/05/20(Wed) 12:18, Mark Kettenis wrote:
> > Date: Wed, 20 May 2020 11:33:24 +0200
> > From: Martin Pieuchot <[email protected]>
> >
> > Diff below implements kqfilter for the 3 remaining drivers in the tree,
> > that I could find, supporting poll(2) but not kqueue(2).
> >
> > magma(4) and spif(4) call seltrue() so their diff is trivial.
> >
> > This change is required to be able to switch poll(2) and select(2) to
> > use the *kqfilter() handlers on sparc64. If one values coherency, it
> > also makes sense on its own.
> >
> > ok?
>
> Nope. The filt_vldcwrite() implementation is defenitely wrong as it
> looks at the rx queue instead of the tx queue.
Diff below fixed the cbus_intr_setenabled() line and `avail' calculation.
Is it what you were pointing?
> But even then, I'm not sure if this is doing the right thing. Si the
> way the code enables interrupts compatible with kqueue(2)? In the
> current implementation, enabling interrupts is closely tied to the
> selrecord() call and disabling interrupts happens at the same time as
> the selwakeup().
When a kevent is registered to a kqueue, the corresponding filter
function, pointed by `f_event', is called. This is similar to calling
`fo_poll' inside pollscan() before going to sleep.
When `f_event' returns a non-0 value, an allocated descriptor representing
the event, `kn' (or knote), is put in the kqueue.
If this didn't happen when the kevent has been registered, either via
kevent(2) or by calling kqueue_register() inside sys_ppoll(), it might
happen when selwakeup() occurs. Because selwakeup() calls knote().
To my understanding this does the same, did I miss anything?
> It really is hard to tell for me to tell what is supposed to happen
> here since there is no kqueue(9) that documents how this is supposed to
> work.
Agreed, that's why it is important to discuss and build knowledge :)
Index: arch/sparc64/dev/vldcp.c
===================================================================
RCS file: /cvs/src/sys/arch/sparc64/dev/vldcp.c,v
retrieving revision 1.19
diff -u -p -r1.19 vldcp.c
--- arch/sparc64/dev/vldcp.c 19 Dec 2019 12:04:38 -0000 1.19
+++ arch/sparc64/dev/vldcp.c 20 May 2020 12:37:27 -0000
@@ -70,6 +70,11 @@ struct vldcp_softc {
int vldcp_match(struct device *, void *, void *);
void vldcp_attach(struct device *, struct device *, void *);
+void filt_vldcprdetach(struct knote *);
+void filt_vldcpwdetach(struct knote *);
+int filt_vldcpread(struct knote *, long);
+int filt_vldcpwrite(struct knote *, long);
+int vldcpkqfilter(dev_t, struct knote *);
struct cfattach vldcp_ca = {
sizeof(struct vldcp_softc), vldcp_match, vldcp_attach
@@ -614,4 +619,122 @@ vldcppoll(dev_t dev, int events, struct
}
splx(s);
return revents;
+}
+
+void
+filt_vldcprdetach(struct knote *kn)
+{
+ struct vldcp_softc *sc = (void *)kn->kn_hook;
+ int s;
+
+ s = spltty();
+ klist_remove(&sc->sc_rsel.si_note, kn);
+ splx(s);
+}
+
+void
+filt_vldcpwdetach(struct knote *kn)
+{
+ struct vldcp_softc *sc = (void *)kn->kn_hook;
+ int s;
+
+ s = spltty();
+ klist_remove(&sc->sc_wsel.si_note, kn);
+ splx(s);
+}
+
+int
+filt_vldcpread(struct knote *kn, long hint)
+{
+ struct vldcp_softc *sc = (void *)kn->kn_hook;
+ struct ldc_conn *lc = &sc->sc_lc;
+ uint64_t head, tail, avail, state;
+ int s, err;
+
+ s = spltty();
+ err = hv_ldc_rx_get_state(lc->lc_id, &head, &tail, &state);
+ if (err == 0 && state == LDC_CHANNEL_UP && head != tail) {
+ avail = (head - tail) / sizeof(struct ldc_pkt) +
+ lc->lc_rxq->lq_nentries - 1;
+ avail %= lc->lc_rxq->lq_nentries;
+ kn->kn_data = avail;
+ } else {
+ cbus_intr_setenabled(sc->sc_bustag, sc->sc_rx_ino,
+ INTR_ENABLED);
+ }
+ splx(s);
+
+ return (kn->kn_data > 0);
+}
+
+int
+filt_vldcwrite(struct knote *kn, long hint)
+{
+ struct vldcp_softc *sc = (void *)kn->kn_hook;
+ struct ldc_conn *lc = &sc->sc_lc;
+ uint64_t head, tail, avail, state;
+ int s, err;
+
+ s = spltty();
+ err = hv_ldc_tx_get_state(lc->lc_id, &head, &tail, &state);
+ if (err == 0 && state == LDC_CHANNEL_UP && head != tail) {
+ avail = (head - tail) / sizeof(struct ldc_pkt) +
+ lc->lc_txq->lq_nentries - 1;
+ avail %= lc->lc_txq->lq_nentries;
+ kn->kn_data = avail;
+ } else {
+ cbus_intr_setenabled(sc->sc_bustag, sc->sc_tx_ino,
+ INTR_ENABLED);
+ }
+ splx(s);
+
+ return (kn->kn_data > 0);
+}
+
+const struct filterops vldcpread_filtops = {
+ .f_flags = FILTEROP_ISFD,
+ .f_attach = NULL,
+ .f_detach = filt_vldcprdetach,
+ .f_event = filt_vldcpread,
+};
+
+const struct filterops vldcpwrite_filtops = {
+ .f_flags = FILTEROP_ISFD,
+ .f_attach = NULL,
+ .f_detach = filt_vldcpwdetach,
+ .f_event = filt_vldcwrite,
+};
+
+int
+vldcpkqfilter(dev_t dev, struct knote *kn)
+{
+ struct vldcp_softc *sc;
+ struct klist *klist;
+ int s;
+
+ sc = vldcp_lookup(dev);
+ if (sc == NULL)
+ return (ENXIO);
+
+ switch (kn->kn_filter) {
+ case EVFILT_READ:
+ klist = &sc->sc_rsel.si_note;
+ kn->kn_fop = &vldcpread_filtops;
+ break;
+ case EVFILT_WRITE:
+ klist = &sc->sc_wsel.si_note;
+ kn->kn_fop = &vldcpwrite_filtops;
+ break;
+
+ default:
+ return (EINVAL);
+ }
+
+ kn->kn_hook = sc;
+
+ s = spltty();
+ klist_insert(klist, kn);
+ splx(s);
+
+ return (0);
}
Index: arch/sparc64/include/conf.h
===================================================================
RCS file: /cvs/src/sys/arch/sparc64/include/conf.h,v
retrieving revision 1.25
diff -u -p -r1.25 conf.h
--- arch/sparc64/include/conf.h 13 May 2020 08:10:03 -0000 1.25
+++ arch/sparc64/include/conf.h 20 May 2020 09:15:55 -0000
@@ -64,7 +64,8 @@ cdev_decl(vdsp);
#define cdev_gen_init(c,n) { \
dev_init(c,n,open), dev_init(c,n,close), dev_init(c,n,read), \
dev_init(c,n,write), dev_init(c,n,ioctl), (dev_type_stop((*))) nullop, \
- 0, dev_init(c,n,poll), (dev_type_mmap((*))) enodev }
+ 0, dev_init(c,n,poll), (dev_type_mmap((*))) enodev, \
+ 0, 0, dev_init(c,n,kqfilter) }
cdev_decl(cn);
Index: dev/sbus/magma.c
===================================================================
RCS file: /cvs/src/sys/dev/sbus/magma.c,v
retrieving revision 1.31
diff -u -p -r1.31 magma.c
--- dev/sbus/magma.c 18 Feb 2020 00:12:08 -0000 1.31
+++ dev/sbus/magma.c 20 May 2020 09:15:55 -0000
@@ -1340,6 +1340,7 @@ mtty_param(struct tty *tp, struct termio
* mbppwrite write to mbpp
* mbppioctl do ioctl on mbpp
* mbpppoll do poll on mbpp
+ * mbppkqfilter kqueue on mbpp
* mbpp_rw general rw routine
* mbpp_timeout rw timeout
* mbpp_start rw start after delay
@@ -1513,6 +1514,12 @@ int
mbpppoll(dev_t dev, int events, struct proc *p)
{
return (seltrue(dev, events, p));
+}
+
+int
+mbppkqfilter(dev_t dev, struct knote *kn)
+{
+ return (seltrue_kqfilter(dev, kn));
}
int
Index: dev/sbus/spif.c
===================================================================
RCS file: /cvs/src/sys/dev/sbus/spif.c,v
retrieving revision 1.23
diff -u -p -r1.23 spif.c
--- dev/sbus/spif.c 19 Jul 2019 00:17:15 -0000 1.23
+++ dev/sbus/spif.c 20 May 2020 09:15:55 -0000
@@ -91,6 +91,7 @@ int sbppwrite(dev_t, struct uio *, int);
int sbpp_rw(dev_t, struct uio *);
int spifppcintr(void *);
int sbpppoll(dev_t, int, struct proc *);
+int sbppkqfilter(dev_t, struct knote *);
int sbppioctl(dev_t, u_long, caddr_t, int, struct proc *);
struct cfattach spif_ca = {
@@ -1043,6 +1044,11 @@ int
sbpppoll(dev_t dev, int events, struct proc *p)
{
return (seltrue(dev, events, p));
+}
+int
+sbppkqfilter(dev_t dev, struct knote *kn)
+{
+ return (seltrue_kqfilter(dev, kn));
}
int
