[src-draft/trunk]: src/sys/dev/usb Hold the lock over access to the data stru...

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src-all/rev/4a92a330489c
branches:  trunk
changeset: 937308:4a92a330489c
user:      Taylor R Campbell <riastradh%NetBSD.org@localhost>
date:      Sun Aug 16 00:36:24 2020 +0000

description:
Hold the lock over access to the data structures it covers.

Still not MPSAFE, but progress.

diffstat:

 sys/dev/usb/ugen.c |  86 ++++++++++++++++++++++++++++++++---------------------
 1 files changed, 51 insertions(+), 35 deletions(-)

diffs (138 lines):

diff -r ddb21176686b -r 4a92a330489c sys/dev/usb/ugen.c
--- a/sys/dev/usb/ugen.c        Sun Aug 16 00:31:06 2020 +0000
+++ b/sys/dev/usb/ugen.c        Sun Aug 16 00:36:24 2020 +0000
@@ -1964,12 +1964,18 @@
 {
        struct ugen_endpoint *sce = kn->kn_hook;
        struct ugen_softc *sc = sce->sc;
+       int ret;
 
-       if (sc->sc_dying)
-               return 0;
+       mutex_enter(&sc->sc_lock);
+       if (sc->sc_dying) {
+               ret = 0;
+       } else {
+               kn->kn_data = sce->q.c_cc;
+               ret = kn->kn_data > 0;
+       }
+       mutex_exit(&sc->sc_lock);
 
-       kn->kn_data = sce->q.c_cc;
-       return kn->kn_data > 0;
+       return ret;
 }
 
 static int
@@ -1977,20 +1983,24 @@
 {
        struct ugen_endpoint *sce = kn->kn_hook;
        struct ugen_softc *sc = sce->sc;
-
-       if (sc->sc_dying)
-               return 0;
+       int ret;
 
-       if (sce->cur == sce->fill)
-               return 0;
-
-       if (sce->cur < sce->fill)
+       mutex_enter(&sc->sc_lock);
+       if (sc->sc_dying) {
+               ret = 0;
+       } else if (sce->cur == sce->fill) {
+               ret = 0;
+       } else if (sce->cur < sce->fill) {
                kn->kn_data = sce->fill - sce->cur;
-       else
+               ret = 1;
+       } else {
                kn->kn_data = (sce->limit - sce->cur) +
                    (sce->fill - sce->ibuf);
+               ret = 1;
+       }
+       mutex_exit(&sc->sc_lock);
 
-       return 1;
+       return ret;
 }
 
 static int
@@ -1998,24 +2008,27 @@
 {
        struct ugen_endpoint *sce = kn->kn_hook;
        struct ugen_softc *sc = sce->sc;
+       int ret;
 
-       if (sc->sc_dying)
-               return 0;
-
-       if (!(sce->state & UGEN_BULK_RA))
+       mutex_enter(&sc->sc_lock);
+       if (sc->sc_dying) {
+               ret = 0;
+       } else if (!(sce->state & UGEN_BULK_RA)) {
                /*
                 * We have no easy way of determining if a read will
                 * yield any data or a write will happen.
                 * So, emulate "seltrue".
                 */
-               return filt_seltrue(kn, hint);
+               ret = filt_seltrue(kn, hint);
+       } else if (sce->ra_wb_used == 0) {
+               ret = 0;
+       } else {
+               kn->kn_data = sce->ra_wb_used;
+               ret = 1;
+       }
+       mutex_exit(&sc->sc_lock);
 
-       if (sce->ra_wb_used == 0)
-               return 0;
-
-       kn->kn_data = sce->ra_wb_used;
-
-       return 1;
+       return ret;
 }
 
 static int
@@ -2023,24 +2036,27 @@
 {
        struct ugen_endpoint *sce = kn->kn_hook;
        struct ugen_softc *sc = sce->sc;
+       int ret;
 
-       if (sc->sc_dying)
-               return 0;
-
-       if (!(sce->state & UGEN_BULK_WB))
+       mutex_enter(&sc->sc_lock);
+       if (sc->sc_dying) {
+               ret = 0;
+       } else if (!(sce->state & UGEN_BULK_WB)) {
                /*
                 * We have no easy way of determining if a read will
                 * yield any data or a write will happen.
                 * So, emulate "seltrue".
                 */
-               return filt_seltrue(kn, hint);
+               ret = filt_seltrue(kn, hint);
+       } else if (sce->ra_wb_used == sce->limit - sce->ibuf) {
+               ret = 0;
+       } else {
+               kn->kn_data = (sce->limit - sce->ibuf) - sce->ra_wb_used;
+               ret = 1;
+       }
+       mutex_exit(&sc->sc_lock);
 
-       if (sce->ra_wb_used == sce->limit - sce->ibuf)
-               return 0;
-
-       kn->kn_data = (sce->limit - sce->ibuf) - sce->ra_wb_used;
-
-       return 1;
+       return ret;
 }
 
 static const struct filterops ugenread_intr_filtops = {