Date: Sun, 7 Jun 2009 21:51:27 GMT From: Scott Long <scottl@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 163741 for review Message-ID: <200906072151.n57LpRnG098192@repoman.freebsd.org>
next in thread | raw e-mail | index | archive | help
http://perforce.freebsd.org/chv.cgi?CH=163741 Change 163741 by scottl@scottl-deimos on 2009/06/07 21:51:11 Iterate dc lists in 3 steps instead of two. This allows the lock to be held while unref'ing dt's, which will allow them to be safely freed in the future. Affected files ... .. //depot/projects/scottl-camlock/src/sys/kern/subr_bus.c#23 edit Differences ... ==== //depot/projects/scottl-camlock/src/sys/kern/subr_bus.c#23 (text+ko) ==== @@ -925,12 +925,13 @@ } mtx_unlock(&devclasses_mtx); - for (i = 0; i < maxunit; i++) { + for (i = 0; i < maxunit; i++) BUS_DRIVER_ADDED(devlist[i], driver); + + mtx_lock(&devclasses_mtx); + for (i = 0; i < maxunit; i++) DT_UNREF(devlist[i]); - } free(devlist, M_BUS); - mtx_lock(&devclasses_mtx); /* * Walk through the children classes. Since we only keep a @@ -991,10 +992,9 @@ dl->driver = driver; TAILQ_INSERT_TAIL(&dc->drivers, dl, link); driver->refs++; /* XXX: kobj_mtx */ + DC_REF(dc); - DC_REF(dc); devclass_driver_added(dc, driver); - DC_UNREF(dc); bus_data_generation_update(); mtx_unlock(&devclasses_mtx); return (0); @@ -1070,30 +1070,40 @@ } } } + mtx_unlock(&devclasses_mtx); - error = 0; for (i = 0; i < maxunit; i++) { dev = devlist[i]; - if ((error = device_detach(dev)) != 0) { - DT_UNREF(dev); + /* + * If device_detach() generates an error, the rest of the + * devices in the list still need to be deref'd. + */ + if ((error = device_detach(dev)) != 0) break; - } device_set_driver(dev, NULL); + } + + mtx_lock(&devclasses_mtx); + for (i = 0; i < maxunit; i++) { + dev = devlist[i]; DT_UNREF(dev); } + free(devlist, M_BUS); - if (error) + if (error) { + mtx_unlock(&devclasses_mtx); return (error); + } - mtx_lock(&devclasses_mtx); TAILQ_REMOVE(&busclass->drivers, dl, link); free(dl, M_BUS); /* XXX: kobj_mtx */ + DC_UNREF(dc); driver->refs--; if (driver->refs == 0) - kobj_class_free((kobj_class_t) driver); + kobj_class_free((kobj_class_t) driver); bus_data_generation_update(); mtx_unlock(&devclasses_mtx); @@ -1169,17 +1179,20 @@ } } } + mtx_unlock(&devclasses_mtx); - error = 0; for (i = 0; i < maxunit; i++) { - dev = devlist[i]; - error = device_quiesce(dev); - DT_UNREF(dev); - if (error) + if ((error = device_quiesce(devlist[i])) != 0) break; } + mtx_lock(&devclasses_mtx); + for (i = 0; i < maxunit; i++) { + DT_UNREF(devlist[i]); + } + mtx_unlock(&devclasses_mtx); + free(devlist, M_BUS); return (error); }
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200906072151.n57LpRnG098192>