From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:59094 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753968AbdBNNj6 (ORCPT ); Tue, 14 Feb 2017 08:39:58 -0500 Date: Tue, 14 Feb 2017 14:39:56 +0100 From: Pavel Machek To: sakari.ailus@iki.fi Cc: sre@kernel.org, pali.rohar@gmail.com, pavel@ucw.cz, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, laurent.pinchart@ideasonboard.com, mchehab@kernel.org, ivo.g.dimitrov.75@gmail.com Subject: [RFC 06/13] v4l2-async: per notifier locking Message-ID: <20170214133956.GA8530@amd> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="y0ulUmNC+osPPQO6" Content-Disposition: inline Sender: linux-media-owner@vger.kernel.org List-ID: --y0ulUmNC+osPPQO6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable =46rom: Sebastian Reichel Without this, camera support breaks boot on N900. Signed-off-by: Ivaylo Dimitrov --- drivers/media/v4l2-core/v4l2-async.c | 54 ++++++++++++++++++--------------= ---- include/media/v4l2-async.h | 2 ++ 2 files changed, 29 insertions(+), 27 deletions(-) diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core= /v4l2-async.c index 96cc733..26492a2 100644 --- a/drivers/media/v4l2-core/v4l2-async.c +++ b/drivers/media/v4l2-core/v4l2-async.c @@ -57,7 +57,6 @@ static bool match_custom(struct v4l2_subdev *sd, struct v= 4l2_async_subdev *asd) =20 static LIST_HEAD(subdev_list); static LIST_HEAD(notifier_list); -static DEFINE_MUTEX(list_lock); =20 static struct v4l2_async_subdev *v4l2_async_belongs(struct v4l2_async_noti= fier *notifier, struct v4l2_subdev *sd) @@ -102,12 +101,15 @@ static int v4l2_async_test_notify(struct v4l2_async_n= otifier *notifier, =20 if (notifier->bound) { ret =3D notifier->bound(notifier, sd, asd); - if (ret < 0) + if (ret < 0) { + dev_warn(notifier->v4l2_dev->dev, "subdev bound failed\n"); return ret; + } } =20 ret =3D v4l2_device_register_subdev(notifier->v4l2_dev, sd); if (ret < 0) { + dev_warn(notifier->v4l2_dev->dev, "subdev register failed\n"); if (notifier->unbind) notifier->unbind(notifier, sd, asd); return ret; @@ -141,7 +143,7 @@ int v4l2_async_notifier_register(struct v4l2_device *v4= l2_dev, { struct v4l2_subdev *sd, *tmp; struct v4l2_async_subdev *asd; - int i; + int ret =3D 0, i; =20 if (!notifier->num_subdevs || notifier->num_subdevs > V4L2_MAX_SUBDEVS) return -EINVAL; @@ -149,6 +151,7 @@ int v4l2_async_notifier_register(struct v4l2_device *v4= l2_dev, notifier->v4l2_dev =3D v4l2_dev; INIT_LIST_HEAD(¬ifier->waiting); INIT_LIST_HEAD(¬ifier->done); + mutex_init(¬ifier->lock); =20 for (i =3D 0; i < notifier->num_subdevs; i++) { asd =3D notifier->subdevs[i]; @@ -168,28 +171,22 @@ int v4l2_async_notifier_register(struct v4l2_device *= v4l2_dev, list_add_tail(&asd->list, ¬ifier->waiting); } =20 - mutex_lock(&list_lock); + /* Keep also completed notifiers on the list */ + list_add(¬ifier->list, ¬ifier_list); + mutex_lock(¬ifier->lock); =20 list_for_each_entry_safe(sd, tmp, &subdev_list, async_list) { - int ret; - asd =3D v4l2_async_belongs(notifier, sd); if (!asd) continue; =20 ret =3D v4l2_async_test_notify(notifier, sd, asd); - if (ret < 0) { - mutex_unlock(&list_lock); - return ret; - } + if (ret < 0) + break; } + mutex_unlock(¬ifier->lock); =20 - /* Keep also completed notifiers on the list */ - list_add(¬ifier->list, ¬ifier_list); - - mutex_unlock(&list_lock); - - return 0; + return ret; } EXPORT_SYMBOL(v4l2_async_notifier_register); =20 @@ -210,7 +207,7 @@ void v4l2_async_notifier_unregister(struct v4l2_async_n= otifier *notifier) "Failed to allocate device cache!\n"); } =20 - mutex_lock(&list_lock); + mutex_lock(¬ifier->lock); =20 list_del(¬ifier->list); =20 @@ -237,7 +234,7 @@ void v4l2_async_notifier_unregister(struct v4l2_async_n= otifier *notifier) put_device(d); } =20 - mutex_unlock(&list_lock); + mutex_unlock(¬ifier->lock); =20 /* * Call device_attach() to reprobe devices @@ -262,6 +259,7 @@ void v4l2_async_notifier_unregister(struct v4l2_async_n= otifier *notifier) } kfree(dev); =20 + mutex_destroy(¬ifier->lock); notifier->v4l2_dev =3D NULL; =20 /* @@ -274,6 +272,7 @@ EXPORT_SYMBOL(v4l2_async_notifier_unregister); int v4l2_async_register_subdev(struct v4l2_subdev *sd) { struct v4l2_async_notifier *notifier; + struct v4l2_async_notifier *tmp; =20 /* * No reference taken. The reference is held by the device @@ -283,24 +282,25 @@ int v4l2_async_register_subdev(struct v4l2_subdev *sd) if (!sd->of_node && sd->dev) sd->of_node =3D sd->dev->of_node; =20 - mutex_lock(&list_lock); - INIT_LIST_HEAD(&sd->async_list); =20 - list_for_each_entry(notifier, ¬ifier_list, list) { - struct v4l2_async_subdev *asd =3D v4l2_async_belongs(notifier, sd); + list_for_each_entry_safe(notifier, tmp, ¬ifier_list, list) { + struct v4l2_async_subdev *asd; + + /* TODO: FIXME: if this is called by ->bound() we will also iterate over= the locked notifier */ + mutex_lock_nested(¬ifier->lock, SINGLE_DEPTH_NESTING); + asd =3D v4l2_async_belongs(notifier, sd); if (asd) { int ret =3D v4l2_async_test_notify(notifier, sd, asd); - mutex_unlock(&list_lock); + mutex_unlock(¬ifier->lock); return ret; } + mutex_unlock(¬ifier->lock); } =20 /* None matched, wait for hot-plugging */ list_add(&sd->async_list, &subdev_list); =20 - mutex_unlock(&list_lock); - return 0; } EXPORT_SYMBOL(v4l2_async_register_subdev); @@ -315,7 +315,7 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *s= d) return; } =20 - mutex_lock(&list_lock); + mutex_lock_nested(¬ifier->lock, SINGLE_DEPTH_NESTING); =20 list_add(&sd->asd->list, ¬ifier->waiting); =20 @@ -324,6 +324,6 @@ void v4l2_async_unregister_subdev(struct v4l2_subdev *s= d) if (notifier->unbind) notifier->unbind(notifier, sd, sd->asd); =20 - mutex_unlock(&list_lock); + mutex_unlock(¬ifier->lock); } EXPORT_SYMBOL(v4l2_async_unregister_subdev); diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h index 8e2a236..690a81f 100644 --- a/include/media/v4l2-async.h +++ b/include/media/v4l2-async.h @@ -84,6 +84,7 @@ struct v4l2_async_subdev { * @waiting: list of struct v4l2_async_subdev, waiting for their drivers * @done: list of struct v4l2_subdev, already probed * @list: member in a global list of notifiers + * @lock: lock hold when the notifier is being processed * @bound: a subdevice driver has successfully probed one of subdevices * @complete: all subdevices have been probed successfully * @unbind: a subdevice is leaving @@ -95,6 +96,7 @@ struct v4l2_async_notifier { struct list_head waiting; struct list_head done; struct list_head list; + struct mutex lock; int (*bound)(struct v4l2_async_notifier *notifier, struct v4l2_subdev *subdev, struct v4l2_async_subdev *asd); --=20 2.1.4 --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --y0ulUmNC+osPPQO6 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlijCKwACgkQMOfwapXb+vJClQCcCTimLK4MAKCmujAHOAisv1Jx Nn4Anj6fvZXaiXx5zJXmq3eps233yMRQ =AyKX -----END PGP SIGNATURE----- --y0ulUmNC+osPPQO6--