[src/trunk]: src/sys/dev/i2c ihidev(4): Take the lock for ihidev_open, ihidev...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/3051380aa520
branches:  trunk
changeset: 359624:3051380aa520
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Fri Jan 14 22:28:23 2022 +0000

description:
ihidev(4): Take the lock for ihidev_open, ihidev_close.

Need this to serialize access to sc_state, sc_refcnt.

XXX Should harmonize this with uhidev(4) and tighten assertions.

diffstat:

 sys/dev/i2c/ihidev.c |  32 +++++++++++++++++++++++---------
 1 files changed, 23 insertions(+), 9 deletions(-)

diffs (80 lines):

diff -r 4e025c699b6b -r 3051380aa520 sys/dev/i2c/ihidev.c
--- a/sys/dev/i2c/ihidev.c      Fri Jan 14 22:26:45 2022 +0000
+++ b/sys/dev/i2c/ihidev.c      Fri Jan 14 22:28:23 2022 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: ihidev.c,v 1.23 2022/01/14 22:26:45 riastradh Exp $ */
+/* $NetBSD: ihidev.c,v 1.24 2022/01/14 22:28:23 riastradh Exp $ */
 /* $OpenBSD ihidev.c,v 1.13 2017/04/08 02:57:23 deraadt Exp $ */
 
 /*-
@@ -54,7 +54,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ihidev.c,v 1.23 2022/01/14 22:26:45 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ihidev.c,v 1.24 2022/01/14 22:28:23 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -882,22 +882,31 @@
 ihidev_open(struct ihidev *scd)
 {
        struct ihidev_softc *sc = scd->sc_parent;
+       int error;
 
        DPRINTF(("%s: %s: state=%d refcnt=%d\n", sc->sc_dev.dv_xname,
            __func__, scd->sc_state, sc->sc_refcnt));
 
-       if (scd->sc_state & IHIDEV_OPEN)
-               return (EBUSY);
+       mutex_enter(&sc->sc_lock);
+
+       if (scd->sc_state & IHIDEV_OPEN) {
+               error = EBUSY;
+               goto out;
+       }
 
        scd->sc_state |= IHIDEV_OPEN;
 
-       if (sc->sc_refcnt++ || sc->sc_isize == 0)
-               return (0);
+       if (sc->sc_refcnt++ || sc->sc_isize == 0) {
+               error = 0;
+               goto out;
+       }
 
        /* power on */
        ihidev_reset(sc, false);
+       error = 0;
 
-       return (0);
+out:   mutex_exit(&sc->sc_lock);
+       return error;
 }
 
 void
@@ -908,17 +917,22 @@
        DPRINTF(("%s: %s: state=%d refcnt=%d\n", sc->sc_dev.dv_xname,
            __func__, scd->sc_state, sc->sc_refcnt));
 
+       mutex_enter(&sc->sc_lock);
+
+       /* XXX make this an assertion */
        if (!(scd->sc_state & IHIDEV_OPEN))
-               return;
+               goto out;
 
        scd->sc_state &= ~IHIDEV_OPEN;
 
        if (--sc->sc_refcnt)
-               return;
+               goto out;
 
        if (ihidev_hid_command(sc, I2C_HID_CMD_SET_POWER,
            &I2C_HID_POWER_OFF, false))
                aprint_error_dev(sc->sc_dev, "failed to power down\n");
+
+out:   mutex_exit(&sc->sc_lock);
 }
 
 void