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McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org, "Paul E. McKenney" , Maarten Lankhorst , Maxime Ripard , Sean Paul , David Airlie , Daniel Vetter , Tejun Heo , dri-devel@lists.freedesktop.org Subject: [PATCH RFC tip/core/rcu 2/4] drivers/gpu/drm: Dynamically allocate drm_unplug_srcu Date: Tue, 2 Apr 2019 07:29:31 -0700 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190402142816.GA13084@linux.ibm.com> References: <20190402142816.GA13084@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 19040214-0068-0000-0000-000003AF73B4 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010860; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000284; SDB=6.01183284; UDB=6.00619477; IPR=6.00964032; MB=3.00026260; MTD=3.00000008; XFM=3.00000015; UTC=2019-04-02 14:29:36 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19040214-0069-0000-0000-0000480482B1 Message-Id: <20190402142933.14547-2-paulmck@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-04-02_05:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=13 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904020098 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Having DEFINE_SRCU() or DEFINE_STATIC_SRCU() in a loadable module requires that the size of the reserved region be increased, which is not something we really want to be doing. This commit therefore removes the DEFINE_STATIC_SRCU() from drivers/gpu/drm/drm_drv.c in favor of defining drm_unplug_srcu as a simple srcu_struct, initializing it in drm_core_init(), and cleaning it up in drm_core_exit(). In this particular case, drm_unplug_srcu is statically allocated and thus guaranteed to be initially zero. Unfortunately, cleanup_srcu_struct() cannot rely on this in the general case (which includes dynamically allocated srcu_struct structures), and therefore cannot tell whether it is being called on something that has been passed to init_srcu_struct(). Thus the code added to drm_core_init() is a bit non-standard. Reported-by: kbuild test robot Signed-off-by: Paul E. McKenney Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Sean Paul Cc: David Airlie Cc: Daniel Vetter Cc: Tejun Heo Cc: --- drivers/gpu/drm/drm_drv.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c index 381581b01d48..ce4582af814d 100644 --- a/drivers/gpu/drm/drm_drv.c +++ b/drivers/gpu/drm/drm_drv.c @@ -77,7 +77,7 @@ static bool drm_core_init_complete = false; static struct dentry *drm_debugfs_root; -DEFINE_STATIC_SRCU(drm_unplug_srcu); +static struct srcu_struct drm_unplug_srcu; /* * DRM Minors @@ -958,12 +958,18 @@ static void drm_core_exit(void) drm_sysfs_destroy(); idr_destroy(&drm_minors_idr); drm_connector_ida_destroy(); + cleanup_srcu_struct(&drm_unplug_srcu); } static int __init drm_core_init(void) { int ret; + ret = init_srcu_struct(&drm_unplug_srcu); + if (ret) { + DRM_ERROR("Cannot create DRM class: %d\n", ret); + return ret; /* cannot cleanup after failed srcu_struct init. */ + } drm_connector_ida_init(); idr_init(&drm_minors_idr); -- 2.17.1