From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mailout1.w2.samsung.com ([211.189.100.11]:58501 "EHLO usmailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751033AbaCGRiK convert rfc822-to-8bit (ORCPT ); Fri, 7 Mar 2014 12:38:10 -0500 Received: from uscpsbgm2.samsung.com (u115.gpu85.samsung.co.kr [203.254.195.115]) by mailout1.w2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0N22005FZUBK0N50@mailout1.w2.samsung.com> for linux-media@vger.kernel.org; Fri, 07 Mar 2014 12:38:08 -0500 (EST) Date: Fri, 07 Mar 2014 14:38:03 -0300 From: Mauro Carvalho Chehab To: Frank =?UTF-8?B?U2Now6RmZXI=?= Cc: Linux Media Mailing List , Mauro Carvalho Chehab Subject: Re: [PATCH v3] em28xx: Only deallocate struct em28xx after finishing all extensions Message-id: <20140307143803.61543333@samsung.com> In-reply-to: <5319FC34.5000602@googlemail.com> References: <52FBB6BC.7030102@googlemail.com> <1394029372-5322-1-git-send-email-m.chehab@samsung.com> <5319FC34.5000602@googlemail.com> MIME-version: 1.0 Content-type: text/plain; charset=UTF-8 Content-transfer-encoding: 8BIT Sender: linux-media-owner@vger.kernel.org List-ID: Em Fri, 07 Mar 2014 18:04:52 +0100 Frank Schäfer escreveu: > > Am 05.03.2014 15:22, schrieb Mauro Carvalho Chehab: > > We can't free struct em28xx while one of the extensions is still > > using it. > > > > So, add a kref() to control it, freeing it only after the > > extensions fini calls. > > > > Signed-off-by: Mauro Carvalho Chehab > > --- > > drivers/media/usb/em28xx/em28xx-audio.c | 7 ++++++- > > drivers/media/usb/em28xx/em28xx-cards.c | 31 ++++++++++++++++++++++++------- > > drivers/media/usb/em28xx/em28xx-dvb.c | 6 +++++- > > drivers/media/usb/em28xx/em28xx-input.c | 8 +++++++- > > drivers/media/usb/em28xx/em28xx-video.c | 15 ++++++++------- > > drivers/media/usb/em28xx/em28xx.h | 8 ++++++-- > > 6 files changed, 56 insertions(+), 19 deletions(-) > > > > diff --git a/drivers/media/usb/em28xx/em28xx-audio.c b/drivers/media/usb/em28xx/em28xx-audio.c > > index 0f5b6f3e7a3f..f75c0a5494d6 100644 > > --- a/drivers/media/usb/em28xx/em28xx-audio.c > > +++ b/drivers/media/usb/em28xx/em28xx-audio.c > > @@ -301,6 +301,7 @@ static int snd_em28xx_capture_open(struct snd_pcm_substream *substream) > > goto err; > > } > > > > + kref_get(&dev->ref); > > dev->adev.users++; > > mutex_unlock(&dev->lock); > > > > @@ -341,6 +342,7 @@ static int snd_em28xx_pcm_close(struct snd_pcm_substream *substream) > > substream->runtime->dma_area = NULL; > > } > > mutex_unlock(&dev->lock); > > + kref_put(&dev->ref, em28xx_free_device); > > > > return 0; > > } > > @@ -895,6 +897,8 @@ static int em28xx_audio_init(struct em28xx *dev) > > > > em28xx_info("Binding audio extension\n"); > > > > + kref_get(&dev->ref); > > + > > printk(KERN_INFO "em28xx-audio.c: Copyright (C) 2006 Markus " > > "Rechberger\n"); > > printk(KERN_INFO > > @@ -967,7 +971,7 @@ static int em28xx_audio_fini(struct em28xx *dev) > > if (dev == NULL) > > return 0; > > > > - if (dev->has_alsa_audio != 1) { > > + if (!dev->has_alsa_audio) { > > /* This device does not support the extension (in this case > > the device is expecting the snd-usb-audio module or > > doesn't have analog audio support at all) */ > > @@ -986,6 +990,7 @@ static int em28xx_audio_fini(struct em28xx *dev) > > dev->adev.sndcard = NULL; > > } > > > > + kref_put(&dev->ref, em28xx_free_device); > > return 0; > > } > > > > diff --git a/drivers/media/usb/em28xx/em28xx-cards.c b/drivers/media/usb/em28xx/em28xx-cards.c > > index 2fb300e882f0..512448b757c9 100644 > > --- a/drivers/media/usb/em28xx/em28xx-cards.c > > +++ b/drivers/media/usb/em28xx/em28xx-cards.c > > @@ -2939,7 +2939,7 @@ static void flush_request_modules(struct em28xx *dev) > > * unregisters the v4l2,i2c and usb devices > > * called when the device gets disconnected or at module unload > > */ > > -void em28xx_release_resources(struct em28xx *dev) > > +static void em28xx_release_resources(struct em28xx *dev) > > { > > /*FIXME: I2C IR should be disconnected */ > > > > @@ -2956,7 +2956,26 @@ void em28xx_release_resources(struct em28xx *dev) > > > > mutex_unlock(&dev->lock); > > }; > > -EXPORT_SYMBOL_GPL(em28xx_release_resources); > > + > > +/** > > + * em28xx_free_defice() - Free em28xx device > > + * > > + * @ref: struct kref for em28xx device > > + * > > + * This is called when all extensions and em28xx core unregisters a device > > + */ > > +void em28xx_free_device(struct kref *ref) > > +{ > > + struct em28xx *dev = kref_to_dev(ref); > > + > > + em28xx_info("Freeing device\n"); > > + > > + if (!dev->disconnected) > > + em28xx_release_resources(dev); > Hmm... good catch ! > > > + > > + kfree(dev->alt_max_pkt_size_isoc); > > + kfree(dev); > > +} > > > > /* > > * em28xx_init_dev() > > @@ -3409,6 +3428,8 @@ static int em28xx_usb_probe(struct usb_interface *interface, > > dev->dvb_xfer_bulk ? "bulk" : "isoc"); > > } > > > > + kref_init(&dev->ref); > > + > > request_modules(dev); > > > > /* Should be the last thing to do, to avoid newer udev's to > > @@ -3453,11 +3474,7 @@ static void em28xx_usb_disconnect(struct usb_interface *interface) > > em28xx_close_extension(dev); > > > > em28xx_release_resources(dev); > > - > > - if (!dev->users) { > > - kfree(dev->alt_max_pkt_size_isoc); > > - kfree(dev); > > - } > > + kref_put(&dev->ref, em28xx_free_device); > > } > > > > static int em28xx_usb_suspend(struct usb_interface *interface, > > diff --git a/drivers/media/usb/em28xx/em28xx-dvb.c b/drivers/media/usb/em28xx/em28xx-dvb.c > > index d4986bdfbdc3..6dbc71ba2820 100644 > > --- a/drivers/media/usb/em28xx/em28xx-dvb.c > > +++ b/drivers/media/usb/em28xx/em28xx-dvb.c > > @@ -1043,7 +1043,6 @@ static int em28xx_dvb_init(struct em28xx *dev) > > em28xx_info("Binding DVB extension\n"); > > > > dvb = kzalloc(sizeof(struct em28xx_dvb), GFP_KERNEL); > > - > > if (dvb == NULL) { > > em28xx_info("em28xx_dvb: memory allocation failed\n"); > > return -ENOMEM; > > @@ -1521,6 +1520,9 @@ static int em28xx_dvb_init(struct em28xx *dev) > > dvb->adapter.mfe_shared = mfe_shared; > > > > em28xx_info("DVB extension successfully initialized\n"); > > + > > + kref_get(&dev->ref); > > + > > The fini() functions are always called, even if an error occured in init(). > So (in opposition to the open()/close() functions) kref_get() needs to > be called at the beginning of the init() methods. > > "dev->is_audio_only" and "!dev->board.has_dvb" is checked in both > functions (init+fini), so the right place here is one line before or after > > em28xx_info("Binding DVB extension\n"); > > > Everything else looks good. I actually prefer to fix it the other way, at the code for kref_put()... see below > > Regards, > Frank > > > ret: > > em28xx_set_mode(dev, EM28XX_SUSPEND); > > mutex_unlock(&dev->lock); > > @@ -1579,6 +1581,8 @@ static int em28xx_dvb_fini(struct em28xx *dev) > > dev->dvb = NULL; Putting the kref_put() here. This part of the code is only called if dev->dvb it not NULL, and this is only possible to happen if the DVB is properly initialized. > > } > > > > + kref_put(&dev->ref, em28xx_free_device); > > + > > return 0; > > } > > > > diff --git a/drivers/media/usb/em28xx/em28xx-input.c b/drivers/media/usb/em28xx/em28xx-input.c > > index 47a2c1dcccbf..2a9bf667f208 100644 > > --- a/drivers/media/usb/em28xx/em28xx-input.c > > +++ b/drivers/media/usb/em28xx/em28xx-input.c > > @@ -676,6 +676,8 @@ static int em28xx_ir_init(struct em28xx *dev) > > return 0; > > } > > > > + kref_get(&dev->ref); > > + > > if (dev->board.buttons) > > em28xx_init_buttons(dev); > > > > @@ -816,7 +818,7 @@ static int em28xx_ir_fini(struct em28xx *dev) > > > > /* skip detach on non attached boards */ > > if (!ir) > > - return 0; > > + goto ref_put; > > > > if (ir->rc) > > rc_unregister_device(ir->rc); > > @@ -824,6 +826,10 @@ static int em28xx_ir_fini(struct em28xx *dev) > > /* done */ > > kfree(ir); > > dev->ir = NULL; > > + > > +ref_put: > > + kref_put(&dev->ref, em28xx_free_device); > > + > > return 0; > > } > > > > diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c > > index 19af6b3e9e2b..32aa55f033fc 100644 > > --- a/drivers/media/usb/em28xx/em28xx-video.c > > +++ b/drivers/media/usb/em28xx/em28xx-video.c > > @@ -1837,7 +1837,6 @@ static int em28xx_v4l2_open(struct file *filp) > > video_device_node_name(vdev), v4l2_type_names[fh_type], > > dev->users); > > > > - > > if (mutex_lock_interruptible(&dev->lock)) > > return -ERESTARTSYS; > > fh = kzalloc(sizeof(struct em28xx_fh), GFP_KERNEL); > > @@ -1869,6 +1868,7 @@ static int em28xx_v4l2_open(struct file *filp) > > v4l2_device_call_all(&dev->v4l2_dev, 0, tuner, s_radio); > > } > > > > + kref_get(&dev->ref); > > dev->users++; > > > > mutex_unlock(&dev->lock); > > @@ -1926,9 +1926,8 @@ static int em28xx_v4l2_fini(struct em28xx *dev) > > dev->clk = NULL; > > } > > > > - if (dev->users) > > - em28xx_warn("Device is open ! Memory deallocation is deferred on last close.\n"); > > mutex_unlock(&dev->lock); > > + kref_put(&dev->ref, em28xx_free_device); > > > > return 0; > > } > > @@ -1976,11 +1975,9 @@ static int em28xx_v4l2_close(struct file *filp) > > mutex_lock(&dev->lock); > > > > if (dev->users == 1) { > > - /* free the remaining resources if device is disconnected */ > > - if (dev->disconnected) { > > - kfree(dev->alt_max_pkt_size_isoc); > > + /* No sense to try to write to the device */ > > + if (dev->disconnected) > > goto exit; > > - } > > > > /* Save some power by putting tuner to sleep */ > > v4l2_device_call_all(&dev->v4l2_dev, 0, core, s_power, 0); > > @@ -2001,6 +1998,8 @@ static int em28xx_v4l2_close(struct file *filp) > > exit: > > dev->users--; > > mutex_unlock(&dev->lock); > > + kref_put(&dev->ref, em28xx_free_device); > > + > > return 0; > > } > > > > @@ -2515,6 +2514,8 @@ static int em28xx_v4l2_init(struct em28xx *dev) > > > > em28xx_info("V4L2 extension successfully initialized\n"); > > > > + kref_get(&dev->ref); > > + > > mutex_unlock(&dev->lock); > > return 0; > > > > diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h > > index 9e44f5bfc48b..2051fc9fb932 100644 > > --- a/drivers/media/usb/em28xx/em28xx.h > > +++ b/drivers/media/usb/em28xx/em28xx.h > > @@ -32,6 +32,7 @@ > > #include > > #include > > #include > > +#include > > #include > > > > #include > > @@ -536,9 +537,10 @@ struct em28xx_i2c_bus { > > enum em28xx_i2c_algo_type algo_type; > > }; > > > > - > > /* main device struct */ > > struct em28xx { > > + struct kref ref; > > + > > /* generic device properties */ > > char name[30]; /* name (including minor) of the device */ > > int model; /* index in the device_data struct */ > > @@ -710,6 +712,8 @@ struct em28xx { > > struct em28xx_dvb *dvb; > > }; > > > > +#define kref_to_dev(d) container_of(d, struct em28xx, ref) > > + > > struct em28xx_ops { > > struct list_head next; > > char *name; > > @@ -771,7 +775,7 @@ extern struct em28xx_board em28xx_boards[]; > > extern struct usb_device_id em28xx_id_table[]; > > int em28xx_tuner_callback(void *ptr, int component, int command, int arg); > > void em28xx_setup_xc3028(struct em28xx *dev, struct xc2028_ctrl *ctl); > > -void em28xx_release_resources(struct em28xx *dev); > > +void em28xx_free_device(struct kref *ref); > > > > /* Provided by em28xx-camera.c */ > > int em28xx_detect_sensor(struct em28xx *dev); > -- Cheers, Mauro