[src/riastradh-drm2]: src/sys/external/bsd/drm2/drm Manage an opencount for e...

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

details:   https://anonhg.NetBSD.org/src/rev/58c165710d73
branches:  riastradh-drm2
changeset: 788462:58c165710d73
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Wed Jul 24 03:55:17 2013 +0000

description:
Manage an opencount for each drm device to block drm_detach.

diffstat:

 sys/external/bsd/drm2/drm/drm_drv.c |  31 +++++++++++++++++++++++++------
 1 files changed, 25 insertions(+), 6 deletions(-)

diffs (102 lines):

diff -r 0250d42f5aab -r 58c165710d73 sys/external/bsd/drm2/drm/drm_drv.c
--- a/sys/external/bsd/drm2/drm/drm_drv.c       Wed Jul 24 03:55:00 2013 +0000
+++ b/sys/external/bsd/drm2/drm/drm_drv.c       Wed Jul 24 03:55:17 2013 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: drm_drv.c,v 1.1.2.14 2013/07/24 03:55:00 riastradh Exp $       */
+/*     $NetBSD: drm_drv.c,v 1.1.2.15 2013/07/24 03:55:17 riastradh Exp $       */
 
 /*-
  * Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: drm_drv.c,v 1.1.2.14 2013/07/24 03:55:00 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: drm_drv.c,v 1.1.2.15 2013/07/24 03:55:17 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/types.h>
@@ -58,6 +58,7 @@
 struct drm_softc {
        struct drm_device       *sc_drm_dev;
        struct drm_minor        sc_minor[__arraycount(drm_minor_types)];
+       unsigned int            sc_opencount;
 };
 
 static int     drm_match(device_t, cfdata_t, void *);
@@ -259,6 +260,7 @@
        aprint_normal("\n");
 
        sc->sc_drm_dev = dev;
+       sc->sc_opencount = 0;
 
        if (device_unit(self) >= 64) { /* XXX Need to do something here!  */
                aprint_error_dev(self, "can't handle >=64 drm devices!");
@@ -305,6 +307,9 @@
        const struct drm_driver *const driver = dev->driver;
        KASSERT(driver != NULL);
 
+       if (sc->sc_opencount != 0)
+               return EBUSY;
+
        /*
         * XXX Synchronize with drm_fill_in_dev, perhaps with reference
         * to drm_put_dev.
@@ -359,9 +364,11 @@
 static int
 drm_open(dev_t d, int flags, int fmt, struct lwp *l)
 {
+       struct drm_softc *const sc = drm_dev_softc(d);
        struct drm_minor *const dminor = drm_dev_minor(d);
        int fd;
        struct file *fp;
+       unsigned int opencount;
        int error;
 
        if (dminor == NULL) {
@@ -379,16 +386,25 @@
                goto fail0;
        }
 
+       do {
+               opencount = sc->sc_opencount;
+               if (opencount == UINT_MAX) {
+                       error = EBUSY;
+                       goto fail0;
+               }
+       } while (atomic_cas_uint(&sc->sc_opencount, opencount, (opencount + 1))
+           != opencount);
+
        error = fd_allocfile(&fp, &fd);
        if (error)
-               goto fail0;
+               goto fail1;
 
        struct drm_file *const file = kmem_zalloc(sizeof(*file), KM_SLEEP);
 
        /* XXX errno Linux->NetBSD */
        error = -drm_open_file(file, fp, dminor);
        if (error)
-               goto fail2;
+               goto fail3;
 
        error = fd_clone(fp, fd, flags, &drm_fileops, file);
        KASSERT(error == EMOVEFD); /* XXX */
@@ -396,12 +412,15 @@
        /* Success!  (But error has to be EMOVEFD, not 0.)  */
        return error;
 
-fail2:
+fail3:
        kmem_free(file, sizeof(*file));
 
-fail1: __unused
+fail2: __unused
        fd_abort(curproc, fp, fd);
 
+fail1:
+       atomic_dec_uint(&sc->sc_opencount);
+
 fail0:
        return error;
 }